That's all good Ronnie. Pretty much what I've been doing for 40 years. One thing you're missing is the importance of the height of the side wall. The big problem with the height of the side wall with most modern "4x4's" is that they have stupid sized rims. They have 17", 18", 20"!!! rims!!!!! That means they DON NOT FLATTERN OUT much when you drop tyre pressure. The old HiLuxes had 15" rims and could do anything with 31" tyres. Landcruisers and Partrols had 16" rims and could do almost the same ('caused they weighed more with 33"). Please consider this issue. Cheers.
100% agree. The smaller the rim diameter/tyre wall ratio the more off road ability. Lower tyre pressures and lower throttle means more traction. Mostly we need less power and more tyre. 1 needs brain power, the other needs smaller rims.
I think you're forgetting tires have gotten considerably taller and more available. As you go up in tire size, a small wheel becomes a hindrance, not an advantage. 40s are normal now. Ground clearance is king here. 37 on anything less than a 17 inch rim doesn't give any benefit. 40+ on less than a 17in rim is stupid. A 37 on a 17-inch aired down is on another planet compared to a 31 combination. It's also stupid to run a larger rim than needed, but them folks don't wheel hard anyway.
@@GadsdenJL For most of the overlanding / occasional harder track that we do in Aus, we don't need crazy high tyres. This isn't Moab type country. Really tall tyres completely screw the gearing, and considering the km we do on dead flat roads to get anywhere (often in the thousands km per trip), it makes zero sense, that kind of ground clearance isn't necessary. 4WDs had it spot on in the 1980s with the 70/80 series Land Cruisers, Patrols, Defenders. Any of that period's OEM tyre options work as well today as they did then, the Toyota 8Jx16 (various offsets) were perfect, but my favourites for desert travel were high ply rating 7.50R16 on 6.5Jx16. I ran cross-ply Dunlop Universal with tubes on Land Cruiser split rims for years from one end of Africa to the other, zero problems in terrain and conditions that make me wonder how the hell we ever made it. Mention that in today's 4WD forums and they think you must have been mentally disabled in some way. I've done the whole of Aus inside out and round and round several times over on 7.50R16 radials, all the well known tracks / deserts, zero problems. Mega tall tyres - just not necessary.
You are right but I think you can do pretty much anything with 17" wheels. Smaller than that it would be problematic for braking on modern cars especially when weight starts increasing
Excellent advice ! As someone in the states that does a lot of rock crawling and desert, one point missed is that lower pressures reduce impact stress on tyres. I am a huge believer in experimenting with pressures to find the right ones for each terrain, for each vehicle / tyre combination. It makes a massive difference.
Thank you Ronnie! I live in the States and have been 4WD’g for years. And although there’s not a ton of sand or beaches in Colorado, we still have a handful of dunes, and have had friends fall prey to poor tire pressures for the appropriate application. This is a great, “here’s why” video, I’m glad to share!
Finally someone caught up.... we've been driving on 6,7,8 psi in the desert for years and we do that for the full drive and for hours. Just need to add that we mostly use beadlocks. For sand driving it is always 10psi or below
Hi mate, probably the best tire pressure video I've seen. My rule of thumb involves 1/4s. Hit dirt down 1/4 (36 to 27), rough corro's or sand another 1/4 (18) , big trouble, real soft sand/mud another 1/4 (9) leaves 4 or 5 psi for bogged. I agree with your speed advice. Most importantly to me i footprint my tires when loaded. Leaving the fronts as the load doesn't change much i pump the rears and the van (same size wheels) till the footprint matches. I do this on concrete with 2 bits if card and a tape. You'd be surprised how high you need to go in the rear, 200 on the ball and beer fridge full, 56 psi rear to match front 60 in van. 1/4 drop front is way less psi drop than 1/4 rear so this is where i didnt like the 5psi rule. I have been using this system and LT tires for 20 years. I have probably gone through 12 or more sets of tires with over 150000 ks on outback tracks and 5 different cars. I got my first puncture this year with a sidewall pin hole exiting the Simpson at night and not stopping to go up 1/4 from 10 front 16 rear. $400 mistake. Kept pumping it up for return home via Madigan. Thanks for your content and honesty 👍
I'm fairly new to wheelin', but I'm no dummy. So when I see people like you doing such great, actual testing and gathering actual data, I'm hooked. I'll be watching more of your stuff. Thank you!
Great video! I think the advantage of airing down is that not just the bigger foot print, but the softer tire conforms to and, hence, grips the terrain much better. For example, when you roll over a rock the softer tire latches onto it.
As a total noob to offroading (though I "softroaded" my 2010 V6 AWD RAV4 since new), videos like these are extremely helpful to me. In fact, I made an image file and converted the kph to mph to keep in my truck. I just picked up a 2024 Chevy Colorado ZR2 in April, and spent 3 days in Moab within the first 3 weeks of getting it (had an AWESOME time!) and recently did a 1/2 day in Colorado, and look forward to exploring more and raising my skill set. Thanks and keep the great vids coming!
Always a pleasure to listen (and follow) your 4WD videos - highly educational for all 4WD adventurers! Thank you, Ronny, for another well prepared video!
I’ve only applied the 4psi rule when determining the best road pressure. If the pressure increases by more than 4psi (cold vs hot) then the tyre pressure is too low. Slowly increase the pressure until the hot psi temp stays under 4psi from cold.
Graet vid Ronny, some top tips. I think that wide = gives more grip is such a common myth. About to go back to 265 from 285, save some weight, fuel and same grip at lower pressures
In a vehicle with pneumatic tires the PSI in the tire is more or less the ground pressure (plus whatever load is carried by the sidewall), so dropping from 25 to 20 is decreasing ground pressure by about a 1/5, but dropping from 15 to 10 is a reduction of 1/3.
Good info to share - hopefully will give newbs the confidence to use lower pressures and stop needlessly turning every track into a corrugated/ wombat holed horror.
In the US, we call that effect washboard. I air down to 12psi almost as soon as I hit dirt, and it soaks up most of the bumps in combo with my suspension. It's the worst.
I've known all that for 35 years, actually rang Dunlop and asked, they said 18psi in the rough and 12psi in the sand. Another thing is, given what you've demonstrated about the tyre contact getting longer, you're better off with narrower tyres than big fat wide ones because the wide ones push a LOT MORE sand infront of them so your vehicle is working harder and more likely to get stopped.
Back in 1978 l drove my new FJ40 Landcruiser with the factory fitted 750 Dunlop Road Track Majors on 16" Split Rims, all over Frazer Island. I ran the tyres at 12-15psi, for 4 weeks and never got bogged.
I run the same size tire/wheel on my Tacoma here in Arizona in the desert. Gives me almost a 33" diameter, no rubbing and easy to get over obstacles aired down and through soft sand in desert washes (dry stream beds).
Excellent advice Ronny ! We did the Canning with 12psi (hot) and never had an issue, even when coming back down from Halls Creek in 45c heat The only thing we had to do, after we got home was clean the rim beads to stop slow leaks, and thank you Tyrepower for that
Yeah while I appreciate and respect all the things those guys have done over the years, I can’t handle their voices for long. 🙉😂 Keep up the good work Ronnie! 😉👍🏼
Ronny is the OG! When I traveled to Australia on work holiday visa I used his videos and information to get myself and vehicle and starting driving. Great wealth of knowledge and since he lives in WA and it has so many great places that is where it started my journey unlike most that start in the east coast, I lived in Fremantle for 6 months and I must say what a great place I miss it often. Plus little creatures brewery was a stone throw from my apartment lol
I was looking at doing our own video on the subject ! No need any more i could not have said it any better everything was covered and done very well , now i will just share it . Thanks for the well presented content
Life here in South Australia I’m always doing endless trips out along the Coorong/ Salt Creek etc.....some seasons that coast can get real Sketchy.. Luckily for me, owning GQ SWB, 2”lift, 33”MT etc... Over the years I am always playing around, experimenting different psi SoftSketchySand? ..... Imma just go 10psi straight away👌. Loose about 1inch in Diff Clearance when the tyres bag out. But the Track Length gained is as close to a mini skid-steer!!the Car is unstoppable!!
Great info for the newbies, i was dropping pressures before max traxs were invented. But you didn’t talk about zero pressures and the effects! I was stuck on a beach down at Beachport and tide was coming in fast so i removed the valves completely & just drove out, popped a bead but saved the car. BTW if you are stuck near the ocean & want to move in a hurry, pull those valves out and when you hear them whistle, it’s about 8lbs. 😮
Sound, concise advice, gels with what I've experienced, and it's a constant source of frustration when dudes f*k around at 25psi on the dunes and wonder why their trucks keep digging graves. Cheers Ronny!
Been saying this for years. The whole point of 29 inch mtb tires was to get the long foot print and gain the 'roll-over' benefits. Taller = longer. and longer means a grabbing more ground in the direction you want to go. Wide and short is nimble, great for race cars or technical riding, but to get up the hills and over the rocks you need long. Trek had a whole technical demo on it.
Great video. Thanks for covering the sidewall temp issue. I think that is an often under considered factor when choosing pressure for a situation. A more common risk when offroad is destroying a tyre (due to overworking the sidewall) than popping a bead.
Wow very informative. All this was taught to me years ago by one of Africa’s best 4x4 owner/driver’s and trained many Camel Trophy and later 4G participants. He NEVER had fat tyres on his vehicles and where he could he would go taller so that footprint is even longer. He drew his inspiration from skiers, long and skinny. Very good advice about the speed and I never drive fast on the beach or when on the tracks never could see the purpose of doing 80 or a 100 on beaches but thats me. Love your videos Ronnie and thanx for sharing your experience’s. cheers Johnny&Rene
Very useful video. I see that you put a lot of testing, thinking and effort into this. Had a blow-out once after a day of tough corrugation and don't need that experience again. Had to change all 4 tyres after that since I didn't trust them anymore. Back then I was guessing and apparently my tyre pressure was too low. So, this data is very helpful. Will put it into a spreadsheet and print and laminate it.
Very helpful advice w/ the common sense caveat that it depends on the terrain. Thanks for taking the time to film this experiment, and to explain things in plain language.
Offroad, start at 12 PSI. If things are real soft Go down to 8. If you have Bead Locks you can head to 4 if needed. If not, rethink your goals or build.
My rigs showed up on a trailer, they will be broken and leaving on a trailer. Wheeling pressure for me in a samurai was always 5psi. I had antire that would be at 3psi and the end of the day. I never lost a bead. Cooper discoverer ATs are kind of pain to break the bead on, especially when compared to swampers.
best advice I used so far: ditch the gauge, tell by the look. until it looks "quite" deflated. sidewall bulges a lot. You'll be surprised how good your own judgement is.
Its difficult to get all 4 tires 'the same' by looks only, esp. if you are doing it on uneven ground like the side of a gravel, etc. road and you want the rear tires with less pressure than the front.
Thx bro! I know the question is not literally about offroading but let me try regardless. What about when you drive soft-roader with relatively low ground clearence and you find yourself in a deep snow? You have two options: 1) lower the tyres pressure which reduces ground clearence even more, or leave them inflated to normal pressure to keep ground clearence as large as possible. What would be the better approach to maximize ability to cross deep snow areas without being stuck? I found myself many times in that doubt...
We drive in the UAE deserts and Tyre pressures we keep usually around 12psi depending on the sand texture at that time even drop to 10psi regularly and turning wheels are always aggressive but rarely a problem. Go lower freely. 👍🏻
Good info / video. I never heard of the 4 PSI rule. I have always aired down while watching the sidewall bulge. With my BFG K02 3,640 lb rated tires, 15 PSI is where they get a decent bulge and footprint.
If you take the vehicle's weight and divide it by the tires foot print, it will tell you how many PSI of pressure you're tires are carrying (PSI of weight, not psi fo tire pressure). eg: a 2.5 ton vehicle on a tire with a foot print of 20 sq inches (x4 tires) gives you 68.75 psi of pressure under the tire. Drop the tire pressure and increase the foot print to 30 sq inches and you get 45.8 psi under the tire. It's like your vehicle just loss 33% of it's weight. Which is why lower pressures appear to make a vehicle "float" higher on the sand.
I don’t want to advise someone who knows more about 4 wheelers then I will ever know. I ride a 1400cc road bike with a sidecar. I have done the holland track four times. The fisheries road to Israelite bay, and parts of the canning stock route. You are dead right about tyre pressure and footprint length. My experiments found out that’s it’s not only the extra grip, it’s more about the front edge of the tyre has almost no weight on it. Therefore it doesn’t push the sand out of the way, it rides up on it. So it is constantly riding up on the sand at the front. Remember I am in one wheel drive with three wheels on the ground. So the front and the side car wheel have to be pushed up the sand.
1400 cc's ? So a Harley / Indian / Victory ? Or something like a Suzuki (I think) Calavcade ? I'm an Old rider too . " Chairs " are pretty rare these days .
We have been towing a ski boat on the beach for years with an Opel Kadette with no problems, We just looked at the tire and when it balloons nicely we ready to go. On the occasions that we got bogged down in soft sugar sand we went lower, nearly no air to drive out of our hole. The only time we blew up again on the sand is at low tide on the hard pack sand near the waves, to go 80km/h cause of our destination being 30km up the beach. For us, it was never about the pressure, it was the look of the tyre.
In the 1.8T Holden rodeo I used to have, it was the alloytec v6 one. It was heaps fast enough in the sand. Very fun car. I used to do Stockton beach at 18psi without too much trouble. Never got bogged. Got close a few times. I drove 60kmh back to the servo with no trouble. On another instance, my engine started misfiring in a mud track once and we decided to drive it home on 25psi. About 40 mins ar 80kmh. Steering was hard, clutch was hard because of the lack of power. It was not a fun drive 😂
Great video, but I want to touch on the PSI VS Speed. It will vary by vehicle, but there are vehicles out there(WD21 Nissan and some Jeep Models included) that state to run the Tire Pressure at 26 PSI on the HWY. Where did I get this information? Simple, go to the Door Placard on your Vehicle. It will be found on the Driver Door or Door Sil on the Body. Mind you that is for stock size tires within the Factory GVWR. A great example is my 2012 Nissan Frontier. On the Placard it stated to run 35 PSI on all 4 on the HWY. That is also up to the GVWR of 5600 LBS(or 2540 KG). Unless there was a major change that certified a higher GVWR I wouldn't worry about a.higher pressure and I always recommend individuals double check that on their vehicle as it will be different for many.
Very true, I did find an online calculator that tells you tire pressure for tires size to weight of vehicle. I’m running on 37s in a Jeep XJ and it says I can run them to 17psi front and 14psi rear, however I usually run 20-25 for highway.
As soon as you change to a different rated/constructed tire from the factory supplied stuff you should usually ignore what it says on the placard for tire pressure. Use the gvwr and the new tires weight and pressure ratings to get your new psi for front and rear.
@@chrisfanchier2318 in some cases it won’t change at all, but in others the number on the placard will even be higher than the new tires rated psi. Maybe the factory tire is 50psi max and the upgrade has a max of 35psi for a similar weight rating. So many possible variables, one needs to make themself aware of their own unique situation and if you aren’t sure then get more opinions from people who actually know something.
I'll share a bit from my own personal experience. I drive a Jimny sitting on 215/75R15 KM3s. That tire is barely warping under the light weight of that car. For light off-roading I take them down to 12-13 PSI, for technical off-roading, 7-9 PSI, and for sand 5-7 PSI. I never had an issue so far. For on-road driving, I usually go for 30-32 PSI on highways and 26-30 PSI in the city. As Ronny mentioned, I never pass low gear speeds (35-45 Km/h) with low tire pressures. Of course, this is a totally different car and I'm by no means an expert..
You overlooked one piece of valuable information. The tyre manufacturers recommended inflation pressure, for sealed road/highway driving. the tyre speed and load rating are specific to the recommended pressure. sure it's fine to go higher when the car is loaded, or you're doing a lot of highway miles, but the recommended pressure is a good place to start.
2 things. 1. Lower pressures = longer tyre foot print. This gives more lift from the tyre by applying a vertical force further ahead of the axle which helps get up on top on top the road surface, not just more longitudinal grip. Look at the change in geometry (wider footprint = more lateral grip and less lift, longer foot print more longitudinal grip and more lift) 2. I often run 10-11 psi towing on sand with no issue. At lower pressures I can get sand in the bead mating surfaces and have a slow leak. Alright 3. Dropping from 30psi to 25psi is 20%. Dropping from 15% to 10psi is 50%
I took a photo of the table you provided at 8:44 with the speed and psi required. That is helpful information. I don't have beadlock rims, so I am limited to 10-12 psi. With beadlocks, 4x4ers here in Canadian deep mountain snow, take psi down to 5-8 psi, to get the grip tread needed. Dedicated rock crawlers will put calcium into the tires to take advantage of the grip tread at low psi, and give weight at lower center of gravity. I personally run LT315/70R17 11.5 inch Milestar MT tires at 37psi, with a standard Gladiator lift, am seriously looking at the 35 inch Nokia Hakkapeliitta LT3 studded tires for winter, but would like to go to 38x13.5R17LT Milestar Patagonia Mud tires with a 3.5-4.5 inch TeraFlex Extended travel lift to clear those tires.
We usually keep our tires at 40psi on the road and 20psi offroad. We have a 4Runner with 285/70/17 Mickey Thompson Baja Boss AT tires. We don't go on sand much and have never lost a bead on our tires. We don't do super heavy off roading but are now trailering. So higher pressures are needed. Good advice overall.
16psi doing 80km/hr all day on Eastern side of Fraser for years. Also, I have always been an advocate that those cigarette plug inflators aren't useless because in a bog situation it gives you the confidence of dropping to 5psi and going back up to 15psi once you're out. They're useless for inflation back to highway pressure but for a casual 4wder they're a lifeline for self recovery without costing a ton and taking up room.
Speed vs pressure the old rule of thumb is for Kilometers, max speed = 3 x PSI. 10psi = 30klm/h, 20psi = 60kph, etc etc. For Miles per hour, max speed = 2 x PSI. Thats the easy way I was always told to judge it to be safe
@@deltonhedges9948 Rules are great but people need education to begin with and then they can apply rules. Without understanding why and how the rule works they shouldn't even be out there driving.
There isn’t one rule or formula that will cover every vehicle/load/tire/application combination out there so it’s best to connect with experienced people in your area to help get a baseline and fine tune from there.
This is good and simple advice for the P platers in this country. Over the years in my work in the bush, I have seen a lot of stupid people doing unsafe things, tried to give them advice and they basically ignore it.
I haven't done a lot of offroad in the sand, but the first thing a friend told me was to go straight to 15 psi and I had plenty of fun in the dunes and beaches of Argentina with my 1998 LR Discovery TDi.
I always manage speed against the heat of a tyre, after 10mins at 110 I'll jump out and put my hand on the tyre, if its hotter than I'm comfortable with I'll slow down or add pressure, Toyotas stock tyre pressure on a hilux is 29 unloaded so Im quite happy running 25 at 100 and managing the temps depending on loads
Also worth noting factors that will differ the tyre pressures from this video: - vehicle mass - tyre stiffness - tyre and rim size For e.g: A Jimny sitting on stiff, 28" muddies on 15" rims will happily sit at 25 psi for everyday driving. 12 psi is the starting pressure for any offroad driving.
Hey mate, the bulk of this advice is excellent and I do very much enjoy your channel but there are a couple of real traps to be aware of when running your tyre at low pressures, the first of which is that there are pressures which you can cause sidewall failure at travelling anywhere much above walking pace, for your vehicle that might be that 5-10PSI mark, for others, with higher highway tyre pressures that might be 15-20PSI or even higher... The two most important things are monitoring the sidewall behaviour of your tyre and monitoring the temperature... If you're seeing sidewall buckling, use it to get out of where you are, then put air back into it as soon as you can. If you're seeing sidewall temps much about 60 degrees you're also quite likely causing tyre delamination which can cause a radial failure and kill you... If you're keen I'm happy to provide a bit of advice on this.
Excellent advice/info/ helpful understanding Ronny ! Hope you don't mind that I took a photo of the yellow screen with your speed to psi's. I'll be using it out on the beach/tracks. Over the years you've got it all perfected Cobber, thanks again.
The most important takeaway for me is the speed range at which I can travel on normal road with deflated pressures. This happens all the time if there are multiple tracks connected by road.
Funny thing is, if i had heard your 4psi rule id have ignored it straight away as id already be doing as you suggest. Id always aird down before the fun starts. So maybe add that. Going on the beach . Air down to 16 before you go on. Or 15 in this case.
Your videos are getting better and better #RonnyDahl. Thanks for sharing. I've been dropping straight to 10psi for years when gotten stuck or tackling steep dunes for years with never a problem. 265/70 17 is my go-to tyre.
For the speed i use the "Dial-in" method (most usefull on dirt roads) Basically you select a pressure (i guess about 85ish% of highway pressure is a good point to start) and go for a short while (few minutes) at the desired speed. Then you stop and touch the tyre: If its to hot to leave your hand on it your pressure is to low and you raise it up and try again(maybe let them cool a little bit) I did this check frequently before i got my temp sensors as overheating your tyres on a dirt road usually means all 4 die at once(talking from experience😂)
The weight of the vehicle plays a big part, I run 26psi on my Hilux, it weighs 1800kg with me and an eski in it with 35x12.5 and doesn't start to bulge untill about 10psi. So on road I run 26psi and on the beach I run 10psi and if I'm finding it very soft I'll go down to 8 so work my way from there. Never rolled the bead never had an issue.
My advice even to you, quite a long while ago was exactly what you've now said, don't bother with incrimental pressure drops, floor it to what you know will get you out, it makes sense. why risk continuing to get stuck when you know 10psi or even less will get you out. 10psi WILL add width to the tyre, but it doesn't add much gain, LENGTH is what you actually need, and low pressures actually cause an indent in the centre of the tyre so that also aides traction. As far as debeading the tyre, it's all about tyre angle to direction of travel, if you understand steering geometry and things like over steer and under steer (not skidding, but the actual fumdamentals of steering and suspension geometry), you'll understand when too much is too much steering for the speed. Debeading is absolutely relevent to the stresses on the tyre at that moment. Re tyre pressures vs speed, it all depends on what your tyre is, vehicle is and what is safe, there are so many combinations that it's not something anyone can "calculate" unless you know all the data and the state of the tyre.
I recently watched a video comparison of two 33 or 35 inch tall muddies, the difference was one was on an 18 and one on a 15 inch wheel, the amount the higher sidewall, smaller rim tyre could deform around obstacles like rocks compared to the tyre with less sidewall was amazing!
Of course, in the Grenadier, you can monitor tyre pressure and temperature. That way, you can also see the impact of all variables including speed, weight, ambient temperature and road temperature etc. If the temperature is rising too far, air up or slow down. That screen also shows transmission line temperatures too, so it’s pretty handy.
@@Mouldyturnip75 The Grenadier is the only production vehicle I know of that can display the tire temperatures. I don't know of any aftermarket system that shows tire temperatures either.
@@Mouldyturnip75 Tire temperature or air temperature inside the tire? From videos I seen of the Grenadier it shows tire temperature across the tread section width (inner, middle, outer). Your suggestion that I need to "get out more" is condescending and implies you have a higher opinion of yourself than you rightly deserve.
@@XavierduToitCFP Yes, I know that. They have been around for years. I have yet to see one that does tire temperature too. Maybe something that shows tire temp is available to club racers for a few thousand, but I haven't seen anything for commuter cars.
Something I've thought of too Ronny, is the difference between ATs and MTs with the same pressures. 15psi with a good quality MT won't deflate as much as on an AT coz you have stiffer sidewalls. Also, for example my Patrol is 3.5t loaded with myself, partner, all the fluids and gear for camping(without towing), 15psi will look much more deflated on my vehicle than when my vehicle weighed stock. Also, if you take a 31" and a 35" of the same brand and model of tyre, the 35" will have a longer footprint on the same vehicle at 15psi than the 31" on the same rim size because the sidewall will have more flex from having a taller sidewall (although maybe not so much between a LT vs non LT muddy) At the opposite side of the pressures, 40 or even 45 psi isn't enough to get even tyre wear for my vehicle. After 30mins to 1 hr of HW driving, when I feel the tyre with my hand, the shoulders are hot and the centre of the tyre is cool. I'm having to run my HW pressure at 52 psi to get even temp(and therefore even wear) across the tread *running 285/70R17 Wildpeak MT01
Excellent information I really appreciate this I am new to this hobby and I'm trying to get into overlanding maybe a silly request but I live in the US and it would be cool if sometimes you would add a conversion know I can Google it I'm just being lazy😂
Thanks Ronny. There is a missconception that lowering tire pressure would not increse the width of the contact patch. While this is in general true, there are some exceptions. With bfg km2 at 10 psi one can see the sidewalls print on sand making some 20pct wider footprint. I wanted to add a picture, but seems this is not posible. I think this is valid for all flotation tires.
I'll agree, it's all situational, no rule fits every scenario. Example, I popped a tire off my boat trailer on flat ground doing a tight turn. Tandem axles on pavement, tires basically dragging sideways on the asphalt under a 6000lb load.
Have said this for years, always put my pressures down to 15psi off-road. Never seen the point of having 25psi and getting bogged and then have to work hard to get your tyres down and possibly being recovered. Cut out the middle man and have maximum footprint to begin with
Bias ply tires do get wider when lower PSI, they actually start to use the edge tread as road tread when low enough. They have a different characteristic the radial. When fully pumped up they'll even bow out the center tread drastically and the tread takes on a whole different characteristic. Also tanks running in soft ground widen their tracks. See the T34s vs Panzer3s.
As far as max speed on low pressure, I've had a couple longer trips where I am doing multiple trails over several days and didn't feel the need to air up, down, up, down, etc every single time. So I generally air down, usually to 15psi, and leave them that way the whole time. Sometimes that means driving on a paved surface for a few miles at speeds of up to 45 mph. Never really had any issues.
I run 315/75R16 on 7.5" wide wheels with no beadlocks. Never had a tire come off its bead and routinely run ~12-13PSI on very rough rocky trails and as low as 7-8PSI for deep snow.
Ronny great vid , comment for everyone what tyres do the military use and there not wide. tall and skinny, about the best 33 is the 255 85 16 lots of side wall not so much width your going to over strain your drive line , oh and my starting pressure is always 20 psi .
Split rims and 235/85-16 on my 80 diesel for last 25 years 4x diamond chains for mud, triple locked with ARB lockers and winch driven off gearbox pto front and a manual winch rear. Been pulling out bogans since I was a teenager some 30 years ago 😆
Albany local here (lots of soft sand). When it comes to sand driving and psi, I just don't bother with tyre pressures higher than 18. If you already know it's soft, just go straight to 12 and don't get yourself bogged in the first place.
You said it Rony...weight of the vehicle matters if youre concerned about debeading . I have a suzuki samurai on 31" mud terrains . The car weighs 970 kgs only . Even if I go zero psi , the car still doesnt sit on the bead / rim . The tyre sidewall is strong enough to support the weight of the car . But you cant try this stunt with a 2 ton suv. So again the tyre footprint is different for diff vehicles with diff weights .
Pretty helpful and interesting video @ronny! For the tire pressure I would add that it depends also on the weight of the vehicle. And the suspension type, IFS doesn’t put the same lateral forces to the tires than solid axle, specially on-road. With my Coopers STMaxx I don’t like to drive on-road higher than 35psi, they become a rolling stone…🤔
Great video and really great advice the only thing is different tyres have different characteristics when it comes to their footprints but going down to 10 and 5 for emergencies is a good rule of thumb.
Yeah exactly, I have a 1400kg Pajero io and have had a Forester in the past and I found that 40psi is much too high even for highway - it made my AT tyres so much noisier and reduced grip on road. I've found that going from 32psi down to around 21psi when going off road on dirt, mud and rocky tracks quite good, it's also not that much of a penalty in handling on the asphalt and doesn't heat up much but you can definitely notice the difference. I usually pump them up at the nearest service station.
I have never heard your version of the 4 psi rule before. The version of the 4 psi rule that was widely spoken of, going back many years, before TPMS was available, is to do with the amount that the tyre pressure increases, from the cold inflation pressure value, as the tyre heats up after driving for some time. The cold inflation pressure is considered correct if the tyre pressure only increases by 4 psi (though some say to use 6 psi). If the cold inflation pressure is too low the tyre heats up too much, and this heat results in a higher tyre pressure. Not having a satisfactory way of measuring the temperature rise back then it was better to measure the psi increase and use that to determine whether we were using the correct cold inflation pressure.
TPMS- We begin the day at 46 PSI rear axle, goes to 51-52 driving at hwy speeds We begin the day at 36 PSI front axle, usually sits 39-41 at hwy speeds. Caravan axles at 36 PSI usually sits around 38-41 at hwy speeds also. To my way of thinking 4-6 PSI variation as recommended is acceptable. Going lower for grip off road, we don't notice much PSI increase whatsoever, 25 PSI goes to 26 PSI usually, if speed involved may go to 28 PSI only. We've not noticed a big variance with tyre temps in either on or off road situations. Temps mostly vary by which tyres are getting most sunlight, if travelling at night temps hardly vary but PSI increased remain within 4-6 variance irrespective. TPMS- if monitored gives all the confidence required in most circumstances, ignore it at your peril. TPMS great addition to any vehicle plus van.
Ronny, great video, the quality of your videos are amazing, very very professionally put together, you have come a long way from when you started doing this TH-cam caper!
When i was doing beach driving all the time, i honestly stopped checking my pressure when airing down. I just went purely off visuals😅. I knew if it didn't look like there was change, it didn't change enough to matter.
Jack the vehicle on level ground, inflate the tire, should reseal the bead around 45psi, keep inflating a bit to be sure, then deflate to desired pressure and carry on. Done it more times than I can count.
I mean in my ln106 with 33x12.5 15r I run 10 in the rear and 12 in the front all day long on Fraser, coonar and top of baffle system. Never had a drama and do the posted 90kmh all day.
The amount you can deflate is directly related to whether or not you have beadlocks (on my truck, both the outer and inner beads are locked with a locking ring in the middle of the tire) and the weight of your rig and how you're driving.
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That's all good Ronnie. Pretty much what I've been doing for 40 years. One thing you're missing is the importance of the height of the side wall. The big problem with the height of the side wall with most modern "4x4's" is that they have stupid sized rims. They have 17", 18", 20"!!! rims!!!!! That means they DON NOT FLATTERN OUT much when you drop tyre pressure. The old HiLuxes had 15" rims and could do anything with 31" tyres. Landcruisers and Partrols had 16" rims and could do almost the same ('caused they weighed more with 33"). Please consider this issue. Cheers.
100% agree. The smaller the rim diameter/tyre wall ratio the more off road ability. Lower tyre pressures and lower throttle means more traction. Mostly we need less power and more tyre. 1 needs brain power, the other needs smaller rims.
I think you're forgetting tires have gotten considerably taller and more available.
As you go up in tire size, a small wheel becomes a hindrance, not an advantage.
40s are normal now.
Ground clearance is king here.
37 on anything less than a 17 inch rim doesn't give any benefit. 40+ on less than a 17in rim is stupid.
A 37 on a 17-inch aired down is on another planet compared to a 31 combination.
It's also stupid to run a larger rim than needed, but them folks don't wheel hard anyway.
@@GadsdenJL For most of the overlanding / occasional harder track that we do in Aus, we don't need crazy high tyres. This isn't Moab type country. Really tall tyres completely screw the gearing, and considering the km we do on dead flat roads to get anywhere (often in the thousands km per trip), it makes zero sense, that kind of ground clearance isn't necessary. 4WDs had it spot on in the 1980s with the 70/80 series Land Cruisers, Patrols, Defenders. Any of that period's OEM tyre options work as well today as they did then, the Toyota 8Jx16 (various offsets) were perfect, but my favourites for desert travel were high ply rating 7.50R16 on 6.5Jx16.
I ran cross-ply Dunlop Universal with tubes on Land Cruiser split rims for years from one end of Africa to the other, zero problems in terrain and conditions that make me wonder how the hell we ever made it. Mention that in today's 4WD forums and they think you must have been mentally disabled in some way. I've done the whole of Aus inside out and round and round several times over on 7.50R16 radials, all the well known tracks / deserts, zero problems. Mega tall tyres - just not necessary.
@@English_Speaking_Fox Absolutely agree
You are right but I think you can do pretty much anything with 17" wheels. Smaller than that it would be problematic for braking on modern cars especially when weight starts increasing
Excellent advice ! As someone in the states that does a lot of rock crawling and desert, one point missed is that lower pressures reduce impact stress on tyres. I am a huge believer in experimenting with pressures to find the right ones for each terrain, for each vehicle / tyre combination. It makes a massive difference.
Thank you Ronnie! I live in the States and have been 4WD’g for years. And although there’s not a ton of sand or beaches in Colorado, we still have a handful of dunes, and have had friends fall prey to poor tire pressures for the appropriate application. This is a great, “here’s why” video, I’m glad to share!
If you’re not airing down for snow you should try it.
Finally someone caught up.... we've been driving on 6,7,8 psi in the desert for years and we do that for the full drive and for hours. Just need to add that we mostly use beadlocks. For sand driving it is always 10psi or below
I don't have beadlocks and consistently run 10osi with no problems
Hi mate, probably the best tire pressure video I've seen. My rule of thumb involves 1/4s. Hit dirt down 1/4 (36 to 27), rough corro's or sand another 1/4 (18) , big trouble, real soft sand/mud another 1/4 (9) leaves 4 or 5 psi for bogged. I agree with your speed advice. Most importantly to me i footprint my tires when loaded. Leaving the fronts as the load doesn't change much i pump the rears and the van (same size wheels) till the footprint matches. I do this on concrete with 2 bits if card and a tape. You'd be surprised how high you need to go in the rear, 200 on the ball and beer fridge full, 56 psi rear to match front 60 in van. 1/4 drop front is way less psi drop than 1/4 rear so this is where i didnt like the 5psi rule. I have been using this system and LT tires for 20 years. I have probably gone through 12 or more sets of tires with over 150000 ks on outback tracks and 5 different cars. I got my first puncture this year with a sidewall pin hole exiting the Simpson at night and not stopping to go up 1/4 from 10 front 16 rear. $400 mistake. Kept pumping it up for return home via Madigan. Thanks for your content and honesty 👍
I'm fairly new to wheelin', but I'm no dummy. So when I see people like you doing such great, actual testing and gathering actual data, I'm hooked. I'll be watching more of your stuff. Thank you!
Great video! I think the advantage of airing down is that not just the bigger foot print, but the softer tire conforms to and, hence, grips the terrain much better. For example, when you roll over a rock the softer tire latches onto it.
As a total noob to offroading (though I "softroaded" my 2010 V6 AWD RAV4 since new), videos like these are extremely helpful to me. In fact, I made an image file and converted the kph to mph to keep in my truck. I just picked up a 2024 Chevy Colorado ZR2 in April, and spent 3 days in Moab within the first 3 weeks of getting it (had an AWESOME time!) and recently did a 1/2 day in Colorado, and look forward to exploring more and raising my skill set. Thanks and keep the great vids coming!
Always a pleasure to listen (and follow) your 4WD videos - highly educational for all 4WD adventurers! Thank you, Ronny, for another well prepared video!
I’ve only applied the 4psi rule when determining the best road pressure. If the pressure increases by more than 4psi (cold vs hot) then the tyre pressure is too low. Slowly increase the pressure until the hot psi temp stays under 4psi from cold.
Graet vid Ronny, some top tips. I think that wide = gives more grip is such a common myth. About to go back to 265 from 285, save some weight, fuel and same grip at lower pressures
In a vehicle with pneumatic tires the PSI in the tire is more or less the ground pressure (plus whatever load is carried by the sidewall), so dropping from 25 to 20 is decreasing ground pressure by about a 1/5, but dropping from 15 to 10 is a reduction of 1/3.
Good info to share - hopefully will give newbs the confidence to use lower pressures and stop needlessly turning every track into a corrugated/ wombat holed horror.
In the US, we call that effect washboard. I air down to 12psi almost as soon as I hit dirt, and it soaks up most of the bumps in combo with my suspension. It's the worst.
I've known all that for 35 years, actually rang Dunlop and asked, they said 18psi in the rough and 12psi in the sand. Another thing is, given what you've demonstrated about the tyre contact getting longer, you're better off with narrower tyres than big fat wide ones because the wide ones push a LOT MORE sand infront of them so your vehicle is working harder and more likely to get stopped.
I went to 225/95 16s on my d22 and its a world of difference compared to the stupid fat tires it came with
Back in 1978 l drove my new FJ40 Landcruiser with the factory fitted 750 Dunlop Road Track Majors on 16" Split Rims, all over Frazer Island. I ran the tyres at 12-15psi, for 4 weeks and never got bogged.
One of the best off-road tips videos I’ve seen. Def will lower pressures when off roading now.
I feel confirmed with my favorite tire size 235/85R16 - tons of sidewall to flex and not insanely wide to follow every cart track on paved surface.
I run the same size tire/wheel on my Tacoma here in Arizona in the desert. Gives me almost a 33" diameter, no rubbing and easy to get over obstacles aired down and through soft sand in desert washes (dry stream beds).
Excellent advice Ronny !
We did the Canning with 12psi (hot) and never had an issue, even when coming back down from Halls Creek in 45c heat
The only thing we had to do, after we got home was clean the rim beads to stop slow leaks, and thank you Tyrepower for that
*This is so much better than Shawn & Grams Cooking channel!*
After shawn did a video about how used solar panels are being "thrown into a big hole in the ground" i realised he is simply a beer swilling moron.
😂
YUP! So true!
Yeah while I appreciate and respect all the things those guys have done over the years, I can’t handle their voices for long. 🙉😂
Keep up the good work Ronnie! 😉👍🏼
Ronny is the OG! When I traveled to Australia on work holiday visa I used his videos and information to get myself and vehicle and starting driving. Great wealth of knowledge and since he lives in WA and it has so many great places that is where it started my journey unlike most that start in the east coast, I lived in Fremantle for 6 months and I must say what a great place I miss it often. Plus little creatures brewery was a stone throw from my apartment lol
I was looking at doing our own video on the subject ! No need any more i could not have said it any better everything was covered and done very well , now i will just share it . Thanks for the well presented content
Also the ambient temperature is important. If it’s a cold rainy day your tyres will not over heat as easily
That's why here in Wales we run at 1psi.
Life here in South Australia
I’m always doing endless trips out along the Coorong/ Salt Creek etc.....some seasons that coast can get real Sketchy..
Luckily for me, owning GQ SWB, 2”lift, 33”MT etc...
Over the years I am always playing around, experimenting different psi
SoftSketchySand? ..... Imma just go 10psi straight away👌.
Loose about 1inch in Diff Clearance when the tyres bag out.
But the Track Length gained is as close to a mini skid-steer!!the Car is unstoppable!!
Luckily sand doesnt dent diff covers, eh?
Great info for the newbies, i was dropping pressures before max traxs were invented.
But you didn’t talk about zero pressures and the effects!
I was stuck on a beach down at Beachport and tide was coming in fast so i removed the valves completely & just drove out, popped a bead but saved the car.
BTW if you are stuck near the ocean & want to move in a hurry, pull those valves out and when you hear them whistle, it’s about 8lbs. 😮
Sound, concise advice, gels with what I've experienced, and it's a constant source of frustration when dudes f*k around at 25psi on the dunes and wonder why their trucks keep digging graves. Cheers Ronny!
I have been banging on about this for many years to anyone who will listen. From now on I’m gonna just flick people a link to this video. Brilliant!!!
Been saying this for years. The whole point of 29 inch mtb tires was to get the long foot print and gain the 'roll-over' benefits. Taller = longer. and longer means a grabbing more ground in the direction you want to go. Wide and short is nimble, great for race cars or technical riding, but to get up the hills and over the rocks you need long.
Trek had a whole technical demo on it.
Great video. Thanks for covering the sidewall temp issue. I think that is an often under considered factor when choosing pressure for a situation. A more common risk when offroad is destroying a tyre (due to overworking the sidewall) than popping a bead.
Wow very informative.
All this was taught to me years ago by one of Africa’s best 4x4 owner/driver’s and trained many Camel Trophy and later 4G participants. He NEVER had fat tyres on his vehicles and where he could he would go taller so that footprint is even longer. He drew his inspiration from skiers, long and skinny.
Very good advice about the speed and I never drive fast on the beach or when on the tracks never could see the purpose of doing 80 or a 100 on beaches but thats me.
Love your videos Ronnie and thanx for sharing your experience’s.
cheers
Johnny&Rene
Very useful video. I see that you put a lot of testing, thinking and effort into this. Had a blow-out once after a day of tough corrugation and don't need that experience again. Had to change all 4 tyres after that since I didn't trust them anymore. Back then I was guessing and apparently my tyre pressure was too low. So, this data is very helpful. Will put it into a spreadsheet and print and laminate it.
it is not just the footprint but the tyre flex so it floats "as much as it can" and not biting/digging in to the soft surface... all good content.
Newbie here, loving your vids. Clearly explained, well written and great visual examples.
Priceless information for the uninformed. Ronny, the king of off road.
Very helpful advice w/ the common sense caveat that it depends on the terrain. Thanks for taking the time to film this experiment, and to explain things in plain language.
Great point at the end, about less force required to recover!
Offroad, start at 12 PSI. If things are real soft Go down to 8. If you have Bead Locks you can head to 4 if needed. If not, rethink your goals or build.
My rigs showed up on a trailer, they will be broken and leaving on a trailer. Wheeling pressure for me in a samurai was always 5psi. I had antire that would be at 3psi and the end of the day. I never lost a bead. Cooper discoverer ATs are kind of pain to break the bead on, especially when compared to swampers.
Dammit, Ronny. I was slowly drifting off for a nap, when that horn scared the crap out of me🤣
C’ mon man it aint nap time yet!
best advice I used so far: ditch the gauge, tell by the look. until it looks "quite" deflated. sidewall bulges a lot. You'll be surprised how good your own judgement is.
Its difficult to get all 4 tires 'the same' by looks only, esp. if you are doing it on uneven ground like the side of a gravel, etc. road and you want the rear tires with less pressure than the front.
Thx bro! I know the question is not literally about offroading but let me try regardless. What about when you drive soft-roader with relatively low ground clearence and you find yourself in a deep snow? You have two options: 1) lower the tyres pressure which reduces ground clearence even more, or leave them inflated to normal pressure to keep ground clearence as large as possible. What would be the better approach to maximize ability to cross deep snow areas without being stuck? I found myself many times in that doubt...
We drive in the UAE deserts and Tyre pressures we keep usually around 12psi depending on the sand texture at that time even drop to 10psi regularly and turning wheels are always aggressive but rarely a problem. Go lower freely. 👍🏻
Good info / video.
I never heard of the 4 PSI rule. I have always aired down while watching the sidewall bulge. With my BFG K02 3,640 lb rated tires, 15 PSI is where they get a decent bulge and footprint.
If you take the vehicle's weight and divide it by the tires foot print, it will tell you how many PSI of pressure you're tires are carrying (PSI of weight, not psi fo tire pressure). eg: a 2.5 ton vehicle on a tire with a foot print of 20 sq inches (x4 tires) gives you 68.75 psi of pressure under the tire. Drop the tire pressure and increase the foot print to 30 sq inches and you get 45.8 psi under the tire. It's like your vehicle just loss 33% of it's weight. Which is why lower pressures appear to make a vehicle "float" higher on the sand.
Yeah but nobody measures the tyre footprint. They measure the pressure in the tyre.
I don’t want to advise someone who knows more about 4 wheelers then I will ever know.
I ride a 1400cc road bike with a sidecar. I have done the holland track four times. The fisheries road to Israelite bay, and parts of the canning stock route. You are dead right about tyre pressure and footprint length. My experiments found out that’s it’s not only the extra grip, it’s more about the front edge of the tyre has almost no weight on it. Therefore it doesn’t push the sand out of the way, it rides up on it. So it is constantly riding up on the sand at the front.
Remember I am in one wheel drive with three wheels on the ground.
So the front and the side car wheel have to be pushed up the sand.
1400 cc's ? So a Harley / Indian / Victory ? Or something like a Suzuki (I think) Calavcade ?
I'm an Old rider too . " Chairs " are pretty rare these days .
@@johncunningham4820GSX1400 built for off-road touring.
We have been towing a ski boat on the beach for years with an Opel Kadette with no problems, We just looked at the tire and when it balloons nicely we ready to go.
On the occasions that we got bogged down in soft sugar sand we went lower, nearly no air to drive out of our hole. The only time we blew up again on the sand is at low tide on the hard pack sand near the waves, to go 80km/h cause of our destination being 30km up the beach. For us, it was never about the pressure, it was the look of the tyre.
In the 1.8T Holden rodeo I used to have, it was the alloytec v6 one. It was heaps fast enough in the sand. Very fun car. I used to do Stockton beach at 18psi without too much trouble. Never got bogged. Got close a few times. I drove 60kmh back to the servo with no trouble.
On another instance, my engine started misfiring in a mud track once and we decided to drive it home on 25psi. About 40 mins ar 80kmh. Steering was hard, clutch was hard because of the lack of power. It was not a fun drive 😂
Great video, but I want to touch on the PSI VS Speed. It will vary by vehicle, but there are vehicles out there(WD21 Nissan and some Jeep Models included) that state to run the Tire Pressure at 26 PSI on the HWY. Where did I get this information? Simple, go to the Door Placard on your Vehicle. It will be found on the Driver Door or Door Sil on the Body. Mind you that is for stock size tires within the Factory GVWR. A great example is my 2012 Nissan Frontier. On the Placard it stated to run 35 PSI on all 4 on the HWY. That is also up to the GVWR of 5600 LBS(or 2540 KG). Unless there was a major change that certified a higher GVWR I wouldn't worry about a.higher pressure and I always recommend individuals double check that on their vehicle as it will be different for many.
Very true, I did find an online calculator that tells you tire pressure for tires size to weight of vehicle. I’m running on 37s in a Jeep XJ and it says I can run them to 17psi front and 14psi rear, however I usually run 20-25 for highway.
As soon as you change to a different rated/constructed tire from the factory supplied stuff you should usually ignore what it says on the placard for tire pressure. Use the gvwr and the new tires weight and pressure ratings to get your new psi for front and rear.
@@Chuck-w4c or use the placard as a nice starting point? You would be surprised at how much it won't change.
@@chrisfanchier2318 in some cases it won’t change at all, but in others the number on the placard will even be higher than the new tires rated psi. Maybe the factory tire is 50psi max and the upgrade has a max of 35psi for a similar weight rating. So many possible variables, one needs to make themself aware of their own unique situation and if you aren’t sure then get more opinions from people who actually know something.
I'll share a bit from my own personal experience. I drive a Jimny sitting on 215/75R15 KM3s. That tire is barely warping under the light weight of that car. For light off-roading I take them down to 12-13 PSI, for technical off-roading, 7-9 PSI, and for sand 5-7 PSI. I never had an issue so far. For on-road driving, I usually go for 30-32 PSI on highways and 26-30 PSI in the city. As Ronny mentioned, I never pass low gear speeds (35-45 Km/h) with low tire pressures. Of course, this is a totally different car and I'm by no means an expert..
Great video Rohnny. Tyre deformation is another term to throw into the mix. “How well does a tyre mould and deform around obstacles”
You overlooked one piece of valuable information. The tyre manufacturers recommended inflation pressure, for sealed road/highway driving. the tyre speed and load rating are specific to the recommended pressure. sure it's fine to go higher when the car is loaded, or you're doing a lot of highway miles, but the recommended pressure is a good place to start.
2 things.
1. Lower pressures = longer tyre foot print. This gives more lift from the tyre by applying a vertical force further ahead of the axle which helps get up on top on top the road surface, not just more longitudinal grip. Look at the change in geometry (wider footprint = more lateral grip and less lift, longer foot print more longitudinal grip and more lift)
2. I often run 10-11 psi towing on sand with no issue. At lower pressures I can get sand in the bead mating surfaces and have a slow leak.
Alright 3. Dropping from 30psi to 25psi is 20%. Dropping from 15% to 10psi is 50%
I took a photo of the table you provided at 8:44 with the speed and psi required. That is helpful information. I don't have beadlock rims, so I am limited to 10-12 psi. With beadlocks, 4x4ers here in Canadian deep mountain snow, take psi down to 5-8 psi, to get the grip tread needed. Dedicated rock crawlers will put calcium into the tires to take advantage of the grip tread at low psi, and give weight at lower center of gravity. I personally run LT315/70R17 11.5 inch Milestar MT tires at 37psi, with a standard Gladiator lift, am seriously looking at the 35 inch Nokia Hakkapeliitta LT3 studded tires for winter, but would like to go to 38x13.5R17LT Milestar Patagonia Mud tires with a 3.5-4.5 inch TeraFlex Extended travel lift to clear those tires.
Very good vídeo Ronnie, explaining very clearly the matters of air pressure in tires.
TNX!!
We usually keep our tires at 40psi on the road and 20psi offroad. We have a 4Runner with 285/70/17 Mickey Thompson Baja Boss AT tires. We don't go on sand much and have never lost a bead on our tires. We don't do super heavy off roading but are now trailering. So higher pressures are needed. Good advice overall.
16psi doing 80km/hr all day on Eastern side of Fraser for years.
Also, I have always been an advocate that those cigarette plug inflators aren't useless because in a bog situation it gives you the confidence of dropping to 5psi and going back up to 15psi once you're out.
They're useless for inflation back to highway pressure but for a casual 4wder they're a lifeline for self recovery without costing a ton and taking up room.
Speed vs pressure the old rule of thumb is for Kilometers, max speed = 3 x PSI. 10psi = 30klm/h, 20psi = 60kph, etc etc. For Miles per hour, max speed = 2 x PSI.
Thats the easy way I was always told to judge it to be safe
What about this rule, Ronny. I can remember easy rules like this and I don't do any extreme 4WD, so only need a 'rule of thumb' like this. Is it Ok?
@@deltonhedges9948 Rules are great but people need education to begin with and then they can apply rules. Without understanding why and how the rule works they shouldn't even be out there driving.
There isn’t one rule or formula that will cover every vehicle/load/tire/application combination out there so it’s best to connect with experienced people in your area to help get a baseline and fine tune from there.
This is good and simple advice for the P platers in this country. Over the years in my work in the bush, I have seen a lot of stupid people doing unsafe things, tried to give them advice and they basically ignore it.
I haven't done a lot of offroad in the sand, but the first thing a friend told me was to go straight to 15 psi and I had plenty of fun in the dunes and beaches of Argentina with my 1998 LR Discovery TDi.
This is probably some of the best advise I have ever seen on any 4wd channel, Thankyou, subscribed and liked👍
I always manage speed against the heat of a tyre, after 10mins at 110 I'll jump out and put my hand on the tyre, if its hotter than I'm comfortable with I'll slow down or add pressure, Toyotas stock tyre pressure on a hilux is 29 unloaded so Im quite happy running 25 at 100 and managing the temps depending on loads
Also worth noting factors that will differ the tyre pressures from this video:
- vehicle mass
- tyre stiffness
- tyre and rim size
For e.g:
A Jimny sitting on stiff, 28" muddies on 15" rims will happily sit at 25 psi for everyday driving. 12 psi is the starting pressure for any offroad driving.
Hey mate, the bulk of this advice is excellent and I do very much enjoy your channel but there are a couple of real traps to be aware of when running your tyre at low pressures, the first of which is that there are pressures which you can cause sidewall failure at travelling anywhere much above walking pace, for your vehicle that might be that 5-10PSI mark, for others, with higher highway tyre pressures that might be 15-20PSI or even higher... The two most important things are monitoring the sidewall behaviour of your tyre and monitoring the temperature... If you're seeing sidewall buckling, use it to get out of where you are, then put air back into it as soon as you can. If you're seeing sidewall temps much about 60 degrees you're also quite likely causing tyre delamination which can cause a radial failure and kill you...
If you're keen I'm happy to provide a bit of advice on this.
Excellent advice/info/ helpful understanding Ronny ! Hope you don't mind that I took a photo of the yellow screen with your speed to psi's. I'll be using it out on the beach/tracks. Over the years you've got it all perfected Cobber, thanks again.
The most important takeaway for me is the speed range at which I can travel on normal road with deflated pressures. This happens all the time if there are multiple tracks connected by road.
Funny thing is, if i had heard your 4psi rule id have ignored it straight away as id already be doing as you suggest.
Id always aird down before the fun starts.
So maybe add that. Going on the beach . Air down to 16 before you go on. Or 15 in this case.
Your videos are getting better and better #RonnyDahl. Thanks for sharing.
I've been dropping straight to 10psi for years when gotten stuck or tackling steep dunes for years with never a problem. 265/70 17 is my go-to tyre.
Great no BS good info enforces mostly everything I have learned in 45 years owning 4x4s.
For the speed i use the "Dial-in" method (most usefull on dirt roads)
Basically you select a pressure (i guess about 85ish% of highway pressure is a good point to start) and go for a short while (few minutes) at the desired speed.
Then you stop and touch the tyre: If its to hot to leave your hand on it your pressure is to low and you raise it up and try again(maybe let them cool a little bit)
I did this check frequently before i got my temp sensors as overheating your tyres on a dirt road usually means all 4 die at once(talking from experience😂)
The weight of the vehicle plays a big part, I run 26psi on my Hilux, it weighs 1800kg with me and an eski in it with 35x12.5 and doesn't start to bulge untill about 10psi. So on road I run 26psi and on the beach I run 10psi and if I'm finding it very soft I'll go down to 8 so work my way from there. Never rolled the bead never had an issue.
My advice even to you, quite a long while ago was exactly what you've now said, don't bother with incrimental pressure drops, floor it to what you know will get you out, it makes sense. why risk continuing to get stuck when you know 10psi or even less will get you out. 10psi WILL add width to the tyre, but it doesn't add much gain, LENGTH is what you actually need, and low pressures actually cause an indent in the centre of the tyre so that also aides traction.
As far as debeading the tyre, it's all about tyre angle to direction of travel, if you understand steering geometry and things like over steer and under steer (not skidding, but the actual fumdamentals of steering and suspension geometry), you'll understand when too much is too much steering for the speed.
Debeading is absolutely relevent to the stresses on the tyre at that moment.
Re tyre pressures vs speed, it all depends on what your tyre is, vehicle is and what is safe, there are so many combinations that it's not something anyone can "calculate" unless you know all the data and the state of the tyre.
I recently watched a video comparison of two 33 or 35 inch tall muddies, the difference was one was on an 18 and one on a 15 inch wheel, the amount the higher sidewall, smaller rim tyre could deform around obstacles like rocks compared to the tyre with less sidewall was amazing!
Thanks for a great and simple to understand explanation of tire pressures
Of course, in the Grenadier, you can monitor tyre pressure and temperature. That way, you can also see the impact of all variables including speed, weight, ambient temperature and road temperature etc. If the temperature is rising too far, air up or slow down. That screen also shows transmission line temperatures too, so it’s pretty handy.
@@Mouldyturnip75 The Grenadier is the only production vehicle I know of that can display the tire temperatures. I don't know of any aftermarket system that shows tire temperatures either.
@@Mouldyturnip75 Tire temperature or air temperature inside the tire?
From videos I seen of the Grenadier it shows tire temperature across the tread section width (inner, middle, outer).
Your suggestion that I need to "get out more" is condescending and implies you have a higher opinion of yourself than you rightly deserve.
@@The_Opinion_of_Matt You do get aftermarket tire pressure systems that goes on the inside of the tire and not on your valve.
@@XavierduToitCFP Yes, I know that. They have been around for years. I have yet to see one that does tire temperature too. Maybe something that shows tire temp is available to club racers for a few thousand, but I haven't seen anything for commuter cars.
@@The_Opinion_of_MattI’ve been using one for about 10 years that does both temperature and pressure
Something I've thought of too Ronny, is the difference between ATs and MTs with the same pressures. 15psi with a good quality MT won't deflate as much as on an AT coz you have stiffer sidewalls. Also, for example my Patrol is 3.5t loaded with myself, partner, all the fluids and gear for camping(without towing), 15psi will look much more deflated on my vehicle than when my vehicle weighed stock. Also, if you take a 31" and a 35" of the same brand and model of tyre, the 35" will have a longer footprint on the same vehicle at 15psi than the 31" on the same rim size because the sidewall will have more flex from having a taller sidewall (although maybe not so much between a LT vs non LT muddy)
At the opposite side of the pressures, 40 or even 45 psi isn't enough to get even tyre wear for my vehicle. After 30mins to 1 hr of HW driving, when I feel the tyre with my hand, the shoulders are hot and the centre of the tyre is cool. I'm having to run my HW pressure at 52 psi to get even temp(and therefore even wear) across the tread
*running 285/70R17 Wildpeak MT01
Tire width to wheel width plays a big role on debeading... 10 psi on a 12'' tire on a 10'' rim is in the danger zone but fine on a 8'' rim.
Excellent information I really appreciate this I am new to this hobby and I'm trying to get into overlanding maybe a silly request but I live in the US and it would be cool if sometimes you would add a conversion know I can Google it I'm just being lazy😂
Thanks Ronny. There is a missconception that lowering tire pressure would not increse the width of the contact patch. While this is in general true, there are some exceptions. With bfg km2 at 10 psi one can see the sidewalls print on sand making some 20pct wider footprint. I wanted to add a picture, but seems this is not posible. I think this is valid for all flotation tires.
I'll agree, it's all situational, no rule fits every scenario.
Example, I popped a tire off my boat trailer on flat ground doing a tight turn.
Tandem axles on pavement, tires basically dragging sideways on the asphalt under a 6000lb load.
Oh, 50PSI, BTW
Have said this for years, always put my pressures down to 15psi off-road. Never seen the point of having 25psi and getting bogged and then have to work hard to get your tyres down and possibly being recovered. Cut out the middle man and have maximum footprint to begin with
My off road tires are wide mounted on relatively skinny rims. The things practically beaded them selves before I even put air in them.
Bias ply tires do get wider when lower PSI, they actually start to use the edge tread as road tread when low enough. They have a different characteristic the radial. When fully pumped up they'll even bow out the center tread drastically and the tread takes on a whole different characteristic.
Also tanks running in soft ground widen their tracks. See the T34s vs Panzer3s.
As far as max speed on low pressure, I've had a couple longer trips where I am doing multiple trails over several days and didn't feel the need to air up, down, up, down, etc every single time. So I generally air down, usually to 15psi, and leave them that way the whole time. Sometimes that means driving on a paved surface for a few miles at speeds of up to 45 mph. Never really had any issues.
I run 315/75R16 on 7.5" wide wheels with no beadlocks. Never had a tire come off its bead and routinely run ~12-13PSI on very rough rocky trails and as low as 7-8PSI for deep snow.
Ronny great vid , comment for everyone what tyres do the military use and there not wide. tall and skinny, about the best 33 is the 255 85 16 lots of side wall not so much width your going to over strain your drive line , oh and my starting pressure is always 20 psi .
Split rims and 235/85-16 on my 80 diesel for last 25 years
4x diamond chains for mud, triple locked with ARB lockers and winch driven off gearbox pto front and a manual winch rear. Been pulling out bogans since I was a teenager some 30 years ago 😆
@@superwag634 wide tyers might look tough but in the bush function is the only thing that matters. There's plenty of bogans out there 😁😁😁😁
Thanks for the very informative video 👍
How do tyre pressures affect the fuel economy and wear on the tyre when Highway driving?
Fantastic video Ronny, one hundred percent agree.
Albany local here (lots of soft sand). When it comes to sand driving and psi, I just don't bother with tyre pressures higher than 18. If you already know it's soft, just go straight to 12 and don't get yourself bogged in the first place.
You said it Rony...weight of the vehicle matters if youre concerned about debeading . I have a suzuki samurai on 31" mud terrains . The car weighs 970 kgs only . Even if I go zero psi , the car still doesnt sit on the bead / rim . The tyre sidewall is strong enough to support the weight of the car . But you cant try this stunt with a 2 ton suv. So again the tyre footprint is different for diff vehicles with diff weights .
Not originally from Oz but I never heard of the 4psi rule - and yes, I have done quite a lot of 4x4 driving.
Refreshing video. Good information! Not like others that talk BS. Then give a quick 1/2 fact at the end.
Pretty helpful and interesting video @ronny! For the tire pressure I would add that it depends also on the weight of the vehicle. And the suspension type, IFS doesn’t put the same lateral forces to the tires than solid axle, specially on-road.
With my Coopers STMaxx I don’t like to drive on-road higher than 35psi, they become a rolling stone…🤔
Great video and really great advice the only thing is different tyres have different characteristics when it comes to their footprints but going down to 10 and 5 for emergencies is a good rule of thumb.
Awesome and outstanding as always.Thanks for sharing and taking us along
Good vid, only thing missing was lighter weight vechicles will need less pressure then heavy ones
Yeah exactly, I have a 1400kg Pajero io and have had a Forester in the past and I found that 40psi is much too high even for highway - it made my AT tyres so much noisier and reduced grip on road. I've found that going from 32psi down to around 21psi when going off road on dirt, mud and rocky tracks quite good, it's also not that much of a penalty in handling on the asphalt and doesn't heat up much but you can definitely notice the difference. I usually pump them up at the nearest service station.
Amazing how a you tuber can become an expert on tires now
I have never heard your version of the 4 psi rule before.
The version of the 4 psi rule that was widely spoken of, going back many years, before TPMS was available, is to do with the amount that the tyre pressure increases, from the cold inflation pressure value, as the tyre heats up after driving for some time. The cold inflation pressure is considered correct if the tyre pressure only increases by 4 psi (though some say to use 6 psi).
If the cold inflation pressure is too low the tyre heats up too much, and this heat results in a higher tyre pressure. Not having a satisfactory way of measuring the temperature rise back then it was better to measure the psi increase and use that to determine whether we were using the correct cold inflation pressure.
TPMS-
We begin the day at 46 PSI rear axle, goes to 51-52 driving at hwy speeds
We begin the day at 36 PSI front axle, usually sits 39-41 at hwy speeds.
Caravan axles at 36 PSI usually sits around 38-41 at hwy speeds also.
To my way of thinking 4-6 PSI variation as recommended is acceptable.
Going lower for grip off road, we don't notice much PSI increase whatsoever, 25 PSI goes to 26 PSI usually, if speed involved may go to 28 PSI only.
We've not noticed a big variance with tyre temps in either on or off road situations.
Temps mostly vary by which tyres are getting most sunlight, if travelling at night temps hardly vary but PSI increased remain within 4-6 variance irrespective.
TPMS- if monitored gives all the confidence required in most circumstances, ignore it at your peril. TPMS great addition to any vehicle plus van.
Ronny, great video, the quality of your videos are amazing, very very professionally put together, you have come a long way from when you started doing this TH-cam caper!
When i was doing beach driving all the time, i honestly stopped checking my pressure when airing down. I just went purely off visuals😅. I knew if it didn't look like there was change, it didn't change enough to matter.
Would love a video about re-mounting a tire on the trail!
Jack the vehicle on level ground, inflate the tire, should reseal the bead around 45psi, keep inflating a bit to be sure, then deflate to desired pressure and carry on. Done it more times than I can count.
I mean in my ln106 with 33x12.5 15r I run 10 in the rear and 12 in the front all day long on Fraser, coonar and top of baffle system. Never had a drama and do the posted 90kmh all day.
I addressed and solved all these problems years ago by stopping extreme and silly games on the beach or elsewhere.
The amount you can deflate is directly related to whether or not you have beadlocks (on my truck, both the outer and inner beads are locked with a locking ring in the middle of the tire) and the weight of your rig and how you're driving.