Tire Pressure Explained
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- เผยแพร่เมื่อ 2 เม.ย. 2018
- Tire pressure and how it relates to performance and reliability in a racing environment. Tire pressures can give you a significant competitive advantage over other teams and allow you to perform at your best possible level.
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Strange place to get good tips for mountain biking :D
I'm always amazed how good instructor you are. Of course neither of these topics are difficult to understand, also it would be really hard to break down all of our studies into such details. But if all the teachers and professors in the world worked like you, this planet would be a lot better place for sure. Keep it up, Sir!
György Mohl The world would be a happy place.
György Mohl i agree i use information from the videos on this channel to make me a better safer driver and reduce stress and strain on my car.
Ha! I was just thinking the same thing, I don't rally but do race mountain bikes!
a video on brake balance (via different brake pad materials) would be wonderful!
Underrated channel
What your gonna find is a guy named Wyatt and he is a killer artist !! Haha job thanks guys you know I appreciate you guys and all info that you share !!! Team O'Neil FTW !!
Thank you for this video! I subscribed half way through. The part i was waiting for was the front to back difference in psi. Ima go soften the front a 2 psi and firmen up the rear a psi or 2. I bet i gonna find even more good stuff when i look at your channel. Thank you!
Thanks Gerald!
Excellent guidance, really spot on for street, pavement track, and off-road. Very well done, thank you.
More of such videos. Thank you so much!
Subscribed!
Wow! Very clear and precise tutorial.
You are really good at teaching simple! Keep it up
Great video. Still new to channel, looking forward to previous and forthcoming videos. I don't have many chances to race but still enjoy learning, ready for if the chances arise!
Excellent video, thanks very much
That was very informative, thanks Wyatt!
Very good videos! Could you please one day talk about the different kinds of clutches (single, double, multi, multi oil bath, ...etc)that are use on the rally cars? Highly appreciate it because the way you explained this kind of stuff is amazing...and for free!!
How about a video on what rally modification you can still run reasonably well on the road?
You can run a s2000 car on the road no problem given you gave the right papers. But why would you do that? Roll cage? Nope. Suspension? Maybe. Tires? Hell no. Brakes? No. Engine? No. If you want to drive a racecar in traffic, offcourse you can. But most of the time you will find its really incovenient, uncomfortable, dangerous and too expensive. I have a drift car that still has registration. Do I drive it on ocasion? Yes. Would I drive a more stock car if I had one. In a heart beat.
This is like asking "can't i use a track car as a rock climber like a 4x4" no you idiot you can't.
good video. straightforward. informative.
I love this channel
love this videos
thanx so much
How about body modification that have rally applications and if they're useful or not?Like fenders, wings, vortex generators, cannards etc
Nice one! Thanks! :)
So many value videos
What is the strategy on the pressures when you have more than one simultaneous special stages without a service in between? Do you measure your tyres on the regular section of the road and remove some air to reduce the pressure before the next stage?
I have 2014 mustang GT track pack, my car is staggered; 255/40r 19’s in the front, 275/40zr 19’s in the rear all radials, what’s the lowest tire pressure I could go for best grip for daily driving safety on the streets?
I change my tire wheels from 15 to 16 with 205/65 tire, can I still mentain the same tire pressure?
Can i use that graph psi on road?
Pretty good tutorial but my question about pressures is that once you find the optimal pressure that's going to change depending on road surface whether it's dirt pavement gravel or a mix and also ambient temperature is going to affect grip. Not too mention if it's dry or wet. So there is no magic number you can set your tires and leave it at, you're always going to be adjusting for the surfaces and the weather.
Yes the conditions are definitely going to determine what the "perfect" tire pressure range might be on race day, this is just a basic guide to get people in the right ballpark.
Do you inflate to max tire pressure rating on an unloaded pickup, ie. 80 psi for a 10 ply when you are unloaded,?
Does this approach generally transfer to gravel & dirt, and snow & ice?
Is the shape of your green performance line remotely accurate, it looks surprisingly "peaky" with definite performance drop off either side of the peak at just a few psi change +/-? Would road tyres have more of a plateau at their maximum performance level? Thanks
Hello, thanks for the video, recently I dug into tyre pressures, sidewall deformation, contact patch, etc. my conclusions are close to your, but a little more scientific, so thank.
But, Nitrogen has bigger molecule, please check the volume/weight/temperature tables for Air and Nitrogen, the latter expands a little bit more...
I've never known the right pressure to run gravel rally tires in a light car (Subaru GC). I've never de-beaded or had a flat, but I have no idea if I'm running in the right performance area.
What do you guys at O'Neil run on your GC8 rally car?
If you're running naturally aspirated with a 175 gravel tire, try around 24 or 25 cold... If you ran 205s or something bigger you could go lower, but you'd only want to go with that big a tire if you're turbocharged.
@@Teamoneilrally I must have been running to low of pressure on a Clay dirt circle track in a 99 impreza RS 2.5-5spd. I had a set of glacier grips that are new but I had the front right set at 22 left Front at 18 and RR@20-LR@18 and it was a serious handful and the front end was like jumping up and down kinda like porpusing? I am guessing the tires where rolling under then jumping back up? I was trying to left foot brake to try to keep the tire from unloading and jumping but it didn't work well in the mid corner but worked great for corner entry. There's two more dirt races this spring and I will raise the tire pressure up! Thanks for the info. Bill
I think it's also important to mention that if one uses non-stock tires, use pressure recommend from the manufacturer (for a particular size & for your car) as the baseline instead of owner's manual's. The recommended pressure from the manual is for stock tires and not for "all" tires.
Rice Y Actually I'm wondering why, as why we shouldn't use car manufacturers recommendations as baseline? After all, if I'm using the right size, the amount of air in the Tyre is exactly what the car manufacturers calculated when designing the car, right? What Tyre models are, does not change the air volume within the Tyre, so it should not be the reason to change the baseline Tyre pressure. Please do correct me if I'm wrong.
Also, I couldn't find what you called the "recommended pressure from tyre manufacturer", they only provide Max Allowed psi.
Each brand/model of tire is designed differently; the recommended pressure from the car manufacturer is mostly calculated based on the car's weight for that specific brand/model (design, materials, etc).
For example, I'm running a set of aftermarket performance tires from Falken; even though they're the same size, the pressure setting is different from the OEM tires. (39/36 for Falken instead of 32/29 for stock OEM in my case.)
The tires manufacturers usually have the pressure setting info for your car's make/model; simply give them a call and they should be able to tell you what it is.
Each car has an OEM tire that the manufacturer uses. It will have particular specs for sidewall stiffness, flex, etc, that another brand may not share.
ChesterHsu The manufacturer recommended number is usually set a little high to maximize gas mileage numbers. The recommended number is not the best number for performance.
ON road courses the key is running at the preferred TEMPERATURE. Getting the tire to the right temp which effects it's designed grip potential. Of course that is affected by the tire compound and overall design, size, weight of vehicle, vehicle handling, air venting, temperature of track and atmosphere, pressure in tire and how aggressive the driver is on acc., braking and cornering. The idea is to get the tire temp. where it is preferred and that is accomplished through pressure, aggression and handling primarily. A log should be kept on the temp of the air, track surface, cold tire, warm tire, lap times and other notes. A habit should be made to take temps. and pressures before and after every track session. Also every track and day maybe different, long straights, will heat up the rears. braking, left turns, right turns....fronts....My point pressure is a tool that gets you to ideal temperature of your tires. Also, a good tire provider at racing events should have information to share about recommended pressures/temps. Another suggested skill is learning how to visually read the wear of your tires from race loading. Imho, peace. (also, be careful around nitrogen, it is very deadly, a couple of full breaths and it's lights out!)
How are these principles modified by tire profile?
thanks for the video
i like to ask how bout different stage of rally, if we compare gravel and tarmac
the 'zone' of the tarmac tire would be higher psi?
Most of the time yes, the sweet spot on a tarmac tire will be higher PSI than gravel.
Thanks a lot! good to know that so i know what to dial in when doing some test
What's the correct tire pressure of 205 /55/R16 94W xl. Thanks
luckily watch this video before I go for hill run 1 hour later. Have an NB Miata and just changed rear tire pressure from 34psi to 28psi.
Pretty solid, I calculated 29 front and 27 rear for my girlfriend's NB so you're on the money. (It was more like 28.8F and 27.2R but who's counting)
This video made my blood pressure go up!!
I've found hot pressure, 41/36-43/38psi for optimal tire wear (subaru crosstrek) for my use. For winter weather driving, should drop down to 37/32 for a little more grip, Or should I still aim for the 41/36? (Manufacture recommended 33/32 but that makes front underinflated)
You might end up with a normal "daily" pressure but have a real "winter storm" pressure in your back pocket... If you're at 41/36 you'll definitely find that 37/32 or 35/32 will be better on snow and ice, it just depends how much you're driving on real snow and ice VS pavement and balancing those priorities.
A cold front came through yesterday. 55°F, All season tires, Pressures dropped to 36/31psi so I tried that today. Have warmed up to 39/34 psi. From the look of the tires, for my winter grip min pressure of 35/30psi for bad winter weather conditions. I wouldn't go lower, would have too much sidewall deflection, but it seems to be equal deflection still with the 5psi difference.
I have some blizzaks ws80 winter tires to put on later
So based on my experimentation. For my situation. 37/32 is the durability flattening spot. So somewhere after 33/28psi would be around max grip, sacrificing some durability. Scaling your chart to me
What about fwd cars? Do you lower the front tire pressure alot compared to the rear wheels?
The rears actually end up lower than the fronts a lot of the time just because there's not much weight back there, where in the front you have the engine/trans and everything.A couple guys can easily pick up the back of a Mk2 GTI for example, so you just don't need much air in the tires.
Best mod in my car on slalom was tyre pressure.. :D
is it still safe to lower or raise front and rear tire pressures seperately on an AWD vehicle.Or would the RPM( rotations per mile) of the tires be too different to upset the center diff?
I wouldn’t do it on asphalt in a road car. If you’ve got beefier bits and your racing the car (and have accepted the additional wear and tear) then it should be fine.
Can you add subtitles for this movie?
im having a hard time on this.
my tire size is 195 55 R15
honda city 2011
stock air pressure on car is 32/30 feels under inflated.. kinda good on bumps though but feels wobbly.
I tried 36/34 feels good on the road and tires don't look under inflated.
pretty much confused
Wow I have the same tires! On my CRZ. For the longest time I thought my tires looked flat and under-inflated even though anyone at a shop would tell me they were the right pressure. It bothered the hell out of me that everyone elses tires out there looked nice and round, y'know like perfect donuts! I thought I was an absolute genius when I pumped them up to like 45 psi a few months ago. Felt amazing driving away and they finally looked good to me. Tbh I think I caused some mad wear on the inner treads oops. 36 should be fine, I don't agree with the 32 recommendation at all
Hi, i change my wheel and tire from 255/70r16 to 265/65r17 44psi what would be the exact air pressure of the tire?thanks godbless
Your question is jot complete for a good answer. You have a lot of information missing. Some of you do not know how to ask questions. Provide things like is it street tires or offroad tires and what kind of load tire? You guys should learn how to better ask a question.
What pressure would you start at for a stock awd rally cross gc Impreza using firestone winterforce tires?
generally in RX running a snow tire i run max side wall to keep from de-beading the tire. but in new england we get some rutted up courses and berms like to pop your tire off :D
Depends how rough the course is, but Andrew is spot on that you might have to run them as high as the sidewall allows to keep them on the wheels. If it's smooth, you can go lower. We run tubes in winter tires sometimes as well, not at summer rallycrosses but maybe it'd be something to think about if the rules allow it?
Thanks for the replies. At 40 psi the tire was rolling over due to the soft sidewalls. The wheel lip was getting sanded.
brian, keep uping pressure untill you notice a loss of grip, then drop the pressure 2 psi.
And what about tyre presure and power loose. You have good grip but you need more power.
I got 235 55 R19 tires when i put 32 psi on all 4 tires on my rx350 suv, they look like its flat lol. I put 38psi dont look flat. It says 51 max tire pressure on the tire.
What do you recommend as far as snow or ice tires?
Similar process, it depends on the weight of the car and the size of the tire, but lowering the pressure a little from what's "recommended" will definitely result in more traction but probably less reliability. We sometimes run tubes inside winter tires for racing applications so we can go lower without having the tire come off the wheel.
Thanks. I wasn't sure whether to increase the pressure to get higher pounds per square inch for better bite in snow with my snow tires or lower it. I assume you want more contact patch for ice, which means lowering the pressure.
This reminds me of the crazy hot matrix
How can i know if i am at the left or the right side of the maximum grip?
Experience. But finding out if you have no experience is full trial and error.
If increasing pressure reduces grip, you are on the right side and if increasing pressure increases grip, you are on the left side.
Sir Wyatt! knox. Ha ha Sir. I have been doing this thing called spectator racing. It is when you take your Street car out on the circle track sometimes paved and sometimes it is on dirt. I am going to use my 93 Subaru legacy RS\SS that I have saverly modified to get it as lightweight as possible. I weighed in at the track at 2680. And I am running a set of lightweight Audi S1 magnesium 15" wheels and Toyo proxies RA1 tires in 205-50-15". The question is what kind of air pressure\S on all 4 corner's would you start with? It kinda really Sucks because of the way this type of racing is! There's no warm up or any practice at all! And it's a standing start single lap drag race single eliminator the first few eliminations are tough for me to do because of the Toyo proxies are extremely slick when cold. But when they warm up to operating temp they are fairly good. But I think they should be better than they are! The front left corner weight is #620 RCW#588 Right rear#520 LR #608 car empty on the corner scale and I am#280+- from the tracks scale of #2680. So I did the tire pressure as front right is 28 psi inside left front 26 psi right rear is 26psi and left rear 23psi. And the races are on going with no Brakes to check tire pressure or change it! Is there anything you can glean from the above information that I need to change? My wife has a couple videos of one of the early races on you tube to see them under Tabatha Putnam or Bill Putnam spectator races claremnt nh.. that way you can actually see what the cars attitude looks like. The car is light and the center diff is very strong and healthy so it can be driven by over powering the available grip and set up for a over steer situation but it's a very unsettling feeling while the tires are Cold and very easy to get into trouble or into the wall if Not very careful! Thanks for any help you can provide. And I sometimes have taken the wife's car out there as well as my truck out there as well. Bill
The second set of races is where you can see what the car was doing and how it would go from under steering to over steering quite quickly! And there's a few different tracks and a few years of racing on there. Thanks much. Bill
I would just try it out a few times and set it up so that it’s still okay to drive on while cold, really good when just warming up and then at least okay while fully hot. If you have some cool down time between runs, you shouldn’t sit at fully hot all the time anyway.
Our dragster is between 6 and 7 psi
Rally tire pressures doesn't generally apply to massive wrinkle-wall tires. This is a case of little-car and large-tire.
Interesting!
At AAA speedway what should I put I have 305s and I have a Dodge Challenger
Useless question. Not enough information to help you.
i have 195/65 -15 Federal gravel soft compound on 2850lb RWD rally/rallyX car, currently not turbo.....whats my race sweet spot PSI ? prob 25, ? 23 ?21 !!!!
Trial and error. Also, as he said - remember to check your tire pressures hot as well as cold.
Tooooooo smart for me
I drive a Nissan Juke Tekna and I have just put 35 in each tyre because i didn't know how much to put in as it is a new car. Now I am worried that i have put too much in.........
Might be alright. Check your owner’s manual, your B-pillar or gas cap for a table of tire pressure. If you find nothing, try googling your exact model and tire size and if still no luck, ask your local dealer.
Hi. Which pressure is best for winter tires with spikes on the ice Racing? I want many grip in front , and no grip in rear. (Civic, pirelli ice zero). Thanks.
On the front go maybe a few PSI lower than stock so that you increase your contact patch (more flex and studs on the ice). If you want less grip in the rear, go higher pressure... like 10 over recommended or so, smaller contact patch, fewer studs on the ice.
@@Teamoneilrally thank you very much! I think so!
@@blackpanter6374 where are you racing on the ice? State@classes? Please and thank you. Bill
@@billyputnam6892 hi! In Russia. We have ice on the road in siberia for 8 month of the year. And 90% peoples used studded (with spikes) wheels.
@@blackpanter6374 I am in the US and I live in a state called Vermont and the last few years our winter is around 6-8 months depending upon the mood of old man winter! I have seen quite a few videos of the slippery roads in your country and it always appears to be a old Lauda if that spelled right? Getting crossed up and going around 3-4 times on the pavement. But sometimes that happens with cars running around with to tall of ice studds sticking out past the rubber tires and getting Steel stud Slide! Awhile ago back in my teenage years we used to go to a big parking lot and put the steel lunch pans under the rear tires of a front wheel drive car and lock the parking brake and stick a couple of bungee cords through the tray and over the tires and it makes the ass end of the car Super slippery and then made a Solo line of cone's and stuff to learn how to be right on top of the counter steering and learn how to catch the car from spinning out and it just made us learn quickly on how to get out of trouble when something happens and it just kept us calm as well when things would go wrong. But now in my state there's really no place to go for doing anything like this for fun anymore. And most of the races are so far away as well as being very expensive. Good luck with your race buggy's and have fun! Bill
8:05 Air modecules: *expand*
Pretty sure that was rather a slip of the tongue, but it's awkward-ish
40 PSI Summer 38 Winters...Car runs like an Unicorn!
My min is 35 psi
You drew a 240 Volvo
Nitrogen is a money making scam. The biggest benefit for racing is that it does not put moisture into the tire making it more predictable. On street tires the oxygen and other gasses leak out you top off with more 70%nitrogen air and raise the percentage of nitrogen in the tire. After a couple of rounds of this your tire will have the same amount of nitrogen as a nitrogen tire, plus some moisture.
Our atmosphere is approximately 70% nitrogen, 20% oxygen, 10% other gaseous elements. The theory is nitrogen is to large to leak out, and is more heat/pressure constant. The problem is when you mount a tire there is already atmosphere in the tire. So unless you mount a tire, then pull a vacuum ( 0 in/hg at sea level, and is only achievable in a lab maybe) will you only have nitrogen in a tire.
Racing nitrogen will give you that extra tenth of a second. But in your daily is just a way to milk your wallet.
Most tire shops use a nitrogen filter system that filters out the other gases. They do not do the best job. You can get cylinders of nitrogen from welding supplies companies. Much more pure.
Most shops use a soap solution as a lubricant when mounting a tire on a rim. That moisture stays inside the tire for a long time, invalidating the benefit of dry nitrogen.
Just watched a video on tire pressure just to tune my forza gt40 mk1 🤦♂️
I run 25psi and 30 in rear cus my car understeers. Audi things.
On 33 how much air
Useless question. Ask questions like an educated person. Provide details.
How about motorcycles tires pressure??
alexmail123 run what the motorcycle manufacturer says. If you adjust any just go 2 or 3 psi on each side of the spec. I've been a tech for almost 20 Years. Even racing on road courses we kept the pressure in the 30 psi range, you just run sticky/softer tires. Dirt bikes go much lower though.
Damn he moves a lot while talking
That is because you can't stop looking at him and licking your lips. Just stop it and ypu see he will not be moving a lot.
the highest may not be the fastest but will sure beat the lowest or flat tire, i can bet with you in a race, i used the highest to challenge your lowest (1 psi) or flat tire, if i lose i lose you $1000, if i win i win you $10, why? because i will sure beat you
80 PSI to mount a gravel tire lol
Yeah that's pretty optimistic haha.
When I'm mounting gravel tires I usually try to find something study to hide behind when setting the bead 😳
I run more than 55 psi