You're both actually not on the cake if you realise that and are open to learning. The guys on the cake don't realise they are on it and they make comments telling me I am dead wrong without even watching. They have ideas which cannot be changed as to do so would shatter their fragile self esteem because they would need to admit they don't know.
Great at last someone talks about how weight transfer effects axle loads. Maybe another good topic for a video would be vehicle roof loads in regard to roof racks and tents, dynamic loads, and how that may effect SRT. Tilt ramp for the model Landy to demonstrate???
Yes! Yes! Yes! Archimedes would be proud. Worse I ever saw (yesterday) was a twin axle high at the tow point and the vehicle squatting very low at the rear. Wish I had taken a photo. Nice work Robert.
I've never done any off-roading but I watch all of the videos because I appreciate understanding the principles. I may end up applying the knowledge in my bicycle loads when I haul a trailer for my trips this summer. Fascinating and well laid out with easy to understand diagrams and scenarios, thanks.
@@L2SFBC I beg to differ (I think). Depending upon where the chap attaches his trailer to his bicycle, the ratios would be totally different. Whilst never having towed a trailer with a bicycle, the ones I've seen have invariably had the pivot connection in an area under the seat, so ahead to the rear axle. As such, I would deduce that there would be zero (or close to zero) effect on the bias between front and rear axles of the bicycle. Or, am I missing something here?
All very interesting but can only be worked out if you know the max axle loads front and back. It should be compulsory for a manufacturer to supply ALL these important numbers but some don’t like GWM
Great to see you explain what effect tow mass has on the vehicle axle loads. It’s an area very often overlooked &/or not understood. 👍🏻 ‘Correct Weight Mobile Vehicle Weighing’
great video - thank you. this video highlights the disaster that is the vehicle standards industry. i'd imagine every single 4x4 towing a medium to large caravan is over their rear axle limit.
Fascinating and nice and in-depth. The only thing I didn't notice you mentioning was how the weight is balanced/distributed within the load/caravan and whether or how much that will influence the load weight. Thanks for the insights.
I'm grateful for your knowledge and explanations of this very technical information Robert! I've recently retired without my own income so sadly can't afford to support your fantastic work. Anyhow.. a big thank you mate.
Thank you Shaun - comments, shares, likes help promote what I do, and therefore help me, so that's one way even without being a Patreon. Glad you like my work :-)
My comment got deleted for some reason (probably because it had links in it), so here we go again: Thank you for another great demonstration and adding the axle loads to the calculator. Could you please also test the effects of TBM on stability and various ways to achieve it? There are studies showing that more TBM seems to make the trailer more stable, but none of them so far even tried to figure out WHY this is. There are some speculations, but not really any data, so I'd love to see someone do some proper testing. The variables are: 1. Load distribution: This can be ruled out as previous testing has shown that putting the load further forwards does not really help anything. 2. Axle load/grip of the car: Some people say that the increased stability comes from the increased load on the car's rear axle. If you were to take a trailer with little to no TBM (let's say
Reject all three explanations, please. This myth that "a bit of TBM is good, so more = better" has to die. Look through my tow playlist for more. l2sfbc.com/one-reason-why-add-more-towball-mass-isnt-always-the-right-answer/
@@L2SFBC I'm not saying that more TBM is always better - I actually believe the exact opposite, which is why I'm asking those questions (and why I was the one who suggested adding the axle loads to the calculator under the video about weight distribution). I may have worded the comment poorly because I didn't want to spend an hour re-typing what got deleted because of a link in the original comment, so let me try again: I found a study called "*An experimental investigation of car-trailer high-speed stability*" from the University of Bath in the UK. This study found that 1. Adding TBM (or, as they call is "nose mass") from the original 5 % to 10 % improved the high-speed stability of the trailer and vice versa. 2. However, moving the load closer to the axle to reduce its inertia improved the stability *even more* than increasing the TBM, and 3. increasing the length of the tongue/nose of the trailer *also* brought significant improvements, although doing so *reduces* the TBM (since it's acting on a longer lever). The above already suggests that even the widely-used "10-% rule" may not be true and less TBM on European-style trailers doesn't make them "inherently unstable" like I've seen some Americans claim. But this is not really relevant to this particular video. The relevant part is this: "It was found that an increased nose mass improved the system stability, although the improvement becomes less significant when the nose mass rises above 6-7 per cent of the total weight. *This effect is thought to be caused by the increase in the car rear axle load associated with nose mass that increases the ability of the tyres to generate side forces that damp out the oscillation. In addition, the increased nose mass raises the tow ball friction, which in turn helps to damp out the oscillation.* However, it should be noted that there are limits on the maximum nose mass, partly as a result of structural strength issues and partly because too much nose mass will reduce the front axle load and worsen the handling performance of the vehicle." I initially missed that, later in the study, they *did* actually try a friction coupler and it did help, which confirms that friction also plays a large role in stabilizing the trailer. Now that I'm looking at it, *it looks like the coupler was actually almost as effective as increasing the TBM from 6 % to 10.5 %* (zero-damping speed of a bit over 66 mph with the extra mass/weight vs. 66 with the coupler), which also answers my third question. The only questions that have't been answered therefore are: How much do axle loads matter here? *What would happen if you were to completely remove the TBM and replace it by an equivalent amount of weight in the car, above (or in front of) its rear axle*, so that the rear-axle load would be the same but with no lifting of the front axle?
Good questions. I shall do more with them as there are a lot of 'it depends' in the true answer. But you're on the right lines. Note that friction devices reduce manoeuvrability.
This is obvious to me, but not to many people, I would imagine. This is also why I want to fit air-helper springs to two of my tow wagons that I use mostly for longer distance and heavier towing. :-)
@@snells-window We're not talking heavy loads for me with that vehicle. I'd only tow up to about 2000-2500kg or so, with it. It's just about the amount of gear I tend to have in the wagon's boot at the same time as tongue weight. They're both softly sprung cars, and both will be lowered sooner or later, one already is. I just want hte car to drive level and have some suspension travel for undulations in the road.
@@fredio54 remember that just like the distance of the towbar to the rear axle amplifies the TBM, the TBM can be multiplied significantly further when going through sharp high speed dips like you often find on fast dirt roads. From my understanding, fitting air springs can change the load/stress points to different parts of the chassis, at least in leaf sprung vehicles.
@@snells-window You're not wrong, however think about this: If I go through those same dips/bumps/braking zones/corners with the vehicle heavily laden and sagged badly then the amount of travel available to absorb those surface variations is minimal and the suspension will bottom out and the bump stops will incur a very strong force very early in the impact/compression cycle. This is worse than having sufficient spring rate (of any sort) to cope with the events that unfold.
New to the channel but these videos are great! I'd really like to see one addressing weight distribution hitches vs. air bags (or other supplemental suspension parts) that simply help maintain rear ride height.
Thanks Jack. I do have one on WDH, but not on airbags. I might do one on the merits of keeping the towcar rake as it should be as opposed to dragging the backside. Air suspension is great for this!!!
@@L2SFBC Well that's what I'm wondering🤔.. Does maintaining rear ride height (through stiffened susp) actually serve to adequately distribute weight to the front wheels, as a WD hitch would?
@@L2SFBC This is perhaps a better explanation of my question but it doesn't go into the depth that your videos tend to: th-cam.com/video/XBZu39pQ8Gg/w-d-xo.html
Raising the rear from sagging to level has a tiny effect on weight distribution - a little more to the front. However...the height of the hitch also varies the towball mass, and it behaves opposite whether the trailer is tandem axle or single axle. Confusing hey? So, "it depends" I'm afraid. Raising the rear will never be as effective as a WDH.
Have you done any videos on A-frame flat towing of other vehicles? I'm expert in it, but I think you'd do a good job of explaining it to others. I do know, though, that it's not your area of interest nor that of your viewers, most likely. But perhaps it could be a nice little series to spice things up :-)
@@L2SFBC Fair enough. Crash course here and now, then: 1. Ball and hinge height should be very close to the same - if ball is lower braking causes compressed rear suspension and lightened front suspension like a ball weight - if ball is higher braking causes rear end jacking and increased front end weight - this can result in a sustained low-speed low-force oversteer condition in the tow vehicle (ask me how I know, ha ha) 2. Zero of the towed vehicle's weight is on the wheels of the car being towed and the towed car, unless it has a driver to assist with hills (up AND down if engine runs) the maximum decel G force is 50% if the weights are equal between tow and towed. 3. You cannot reverse easily and you cannot reverse at all without a helper in the towed car or the steering locked 4. Your steering must be free to move as needed when being towed forward - if a driver is inside the towed car they must only use brake/gas - they must not interfere with the steering wheel. 5. Cornering load from the front of the towed vehicle is applied to the rear of the tow vehicle 6. It's effectively the same as towing a trailer with a very long draw bar when moving forward - ie, the turning circle is very large and it's easy to accidentally cut corners and do damage (again, ask me how I know...) 7. If you DO have a driver then it's as if you have a double mass double power vehicle and the entire experience is seamless and easy 8. If you don't have a driver or the brakes are not working on the towed car then keep 2 in mind - it can get bad easily 9. If you're towing an auto and it won't be running and assisting then you must drop the driveshaft or CV axles or the auto will be destroyed by the act of towing because the oil pump is engine driven and key parts will not be lubricated. I built mine to tow my race ute to the track years ago, but have since used it on a number of other vehicles to great success. They're a very nice way to go and especially if you can put a person in the back car to help slow it down (they brake when your brake lights show, they accelerate when they feel you do so and/or they see a hill or are coming out of an intersection or whatever. I prefer it to car-transporter use these days. You just have to know what you're getting into. Kinda like MIG locked diffs - they're great and ultimately predictable, but you have to know what you're doing when you drive one or it can get you into trouble. :-)
Excellent video. Fairly simple math. Do you have any work demonstrating effects of WDH on this situation? Would be of great interest to many caravaners.
Very Interesting and excellent demonstration about how the single axle and tandem axle affect the towball mass, which led me to a question about Load Sharing Tandems. Considering the towball mass, with a true load sharing tandem suspension compared to the the tandem model in your demonstration, which would mimic the independent coil systems on vans lately, (except for the Simplicity Axle LSC) would this have a different effect?. As these are designed to keep the same amount of weight on each axle within suspension travel limits, so would a Load Sharing Tandem setup, act similar to the single axle in regards to TBM?.
My weight distribution/sway control hitch was installed by a professional. I took my truck & caravan to him for installation. Am I correct thinking he should have set all of this up properly? 👍😊
Sorry about that. Simpler version - every 1 kilogram of towball mass means more than 1 kg added to the rear axle load. Don't exceed the rear axle load.
I've come to understand that Tow Ball Weight can be too much, as well as too low. What would you say is the optimal weight on the ball? (I'm aware of wanting to keep the majority of the weight over the axle of the trailer for stability.)
@2.07 if you put more weight on the front even though the vehicle gvm would increase would it also decrease the rear weight and tranfer it to the front? Is it aboute keeping the vehicle sitting level to keep the weight ok or physical weight ay the front or rear to change it.? By far the best trailer weight video on youtubes also.
great video, thanks for posting this. are you going to do another video explaining the same loads but with using weight distribution bars? ( it would be the next logical step) also have you noticed the 'long' tow ball hitches ( generally height adjustable versions) that add to the overhang? do you know of a height adjustable ( or weight distribution hitch unit) that is 'short' ? so your overhang is keep to a minimum? also how does load sharing dual axle trailer suspension act on down ball weight?
@@L2SFBC yes they are evil....... in most circumstances. In my case, I have a Chevy Silverado with a GVM of 5,171kg and a GCM of 11,113kg. The front/rear axle ratings are 2,359kg and 2,812kg respectively (hence the 5,171kg GVM). I tow a 3,500kg Bushtracker caravan....so I'm well within the GCM. However, because of the truck-like rear suspension (it barely budges when I add the 320kg ball weight), the ride when towing was less-than-pleasant. The "fix" for that was to purchase a product called an Airsafe Hitch which gives an airbag cushion between the two vehicles. Unfortunately, the trade-off is both weight (the Airsafe weighs around 35kg) and the increased distance from rear axle to pivot of around 300mm. Fortunately, having such a long wheelbase in the first instance, these trade-offs are well-worth it and I wouldn't tow the van without the Airsafe Hitch.
can you clarify point 5 at the end there - does raising/lowering towball height have less of an effect with single axle vans, or less of an effect with tandems?
I would avoid WDHs unless necessary. They do add weight to the front axle and also the trailer axle. But they have complications. I'd prefer to get a bigger towcar. Also note quite a few manufacturers expressly forbid use of a WDH.
@@L2SFBC yes, just a band-aid for level roads and disconnected if going up a driveway into service station, spoon drain, bull dust holes, speed bumps and the like. I enjoy your spot on presentations and associated views. BTW it is a subject I enjoy but I don't tow with my Dmax, it is just a full time tourer build.
@@L2SFBC so there are no concerns with performance of the trailer not being parallel to the tow vehicle chassis, in terms of braking or stability, outside of the load distribution? Ultimately I want it to be flat, but for instance we are about to put the trailer on my mates BT50 (I have a Hilux) and his ball is 60mm higher. Now we are only towing about 2000kg, so we aren't in the limit. Trying to determine if we have to fork out the coin for an adjustable hitch for a 4400km trip or just send it.
quick question: To calculate the total effect therefore on the rear axle, I'd need to include the vehicle payload weight. What'st the best way to do that? Would I simply add the payload weight from the second row and the boot with the towball effect to complete this analysis for the total rear axle laod? Thanks
@@L2SFBC thanks for your reply! Are there any rules of thumb that can be used to estimate? I may do this for several vehicles I'm looking at purchasing
Do you divide the overhang by the wheelbase or the wheelbase by the overhang, because my WB is 3062 and my overhang is about 920 +/- 10mm and doing the wb by the overhang give a 60kg @ over 199kgs, and thats just nuts, thanks.
If you model trailer had a spring equalizer like most road going tandem axle trailers with leaf springs have, then you would find that the weight isn’t as sensitive to height as they equalize the load. If they have torsion axles that don’t use equalizers, then your explanation is dead on.
yet another comprehensive with an explanation that even i understand (not the brightest candle on the cake) video .. good shit
thank you. please share!
I am with you on that cake! 😁👍
You're both actually not on the cake if you realise that and are open to learning.
The guys on the cake don't realise they are on it and they make comments telling me I am dead wrong without even watching. They have ideas which cannot be changed as to do so would shatter their fragile self esteem because they would need to admit they don't know.
Another great video explaining towing weights, you are doing a great service with this series.
Thanks Brett please share 🙏
Great at last someone talks about how weight transfer effects axle loads. Maybe another good topic for a video would be vehicle roof loads in regard to roof racks and tents, dynamic loads, and how that may effect SRT. Tilt ramp for the model Landy to demonstrate???
So many things on my list...including that. I need staff! Please share if it was useful 👍
This should be compulsory education before signing to buy a caravan. Well done. I was aware of it but you explained it perfectly.
Thanks Wayne, please share!
Yes! Yes! Yes! Archimedes would be proud.
Worse I ever saw (yesterday) was a twin axle high at the tow point and the vehicle squatting very low at the rear. Wish I had taken a photo.
Nice work Robert.
Thank you Denis, please share :-)
Wow, who knows this information out there because I didn't till now. You're a life saver, thanks.
Glad to help! Please share, few others know including some in the industry.
I've never done any off-roading but I watch all of the videos because I appreciate understanding the principles. I may end up applying the knowledge in my bicycle loads when I haul a trailer for my trips this summer. Fascinating and well laid out with easy to understand diagrams and scenarios, thanks.
Thanks Johh yes the principles absolutely overlap!
@@L2SFBC I beg to differ (I think). Depending upon where the chap attaches his trailer to his bicycle, the ratios would be totally different.
Whilst never having towed a trailer with a bicycle, the ones I've seen have invariably had the pivot connection in an area under the seat, so ahead to the rear axle.
As such, I would deduce that there would be zero (or close to zero) effect on the bias between front and rear axles of the bicycle. Or, am I missing something here?
No you're not the force being zero wouldn't mean the principle doesn't work it means the answer is 0
All very interesting but can only be worked out if you know the max axle loads front and back. It should be compulsory for a manufacturer to supply ALL these important numbers but some don’t like GWM
Sadly yes and I agree!!
Yes and others
Try and get the GCM out of Toyota for a new Kluger hybrid
Great to see you explain what effect tow mass has on the vehicle axle loads. It’s an area very often overlooked &/or not understood. 👍🏻
‘Correct Weight Mobile Vehicle Weighing’
Thanks please share!
great video - thank you. this video highlights the disaster that is the vehicle standards industry. i'd imagine every single 4x4 towing a medium to large caravan is over their rear axle limit.
Pretty much yes!
Another great presentation Robert. Thankyou
Very welcome
Fascinating and nice and in-depth. The only thing I didn't notice you mentioning was how the weight is balanced/distributed within the load/caravan and whether or how much that will influence the load weight. Thanks for the insights.
Great point! I cover weight distribution elsewhere on the channel, only so much you can do in one video :-)
I'm grateful for your knowledge and explanations of this very technical information Robert!
I've recently retired without my own income so sadly can't afford to support your fantastic work.
Anyhow.. a big thank you mate.
Thank you Shaun - comments, shares, likes help promote what I do, and therefore help me, so that's one way even without being a Patreon. Glad you like my work :-)
Excellent informative video Robert. Much appreciated
Glad it was helpful! Please share :-)
A great explanation. Very helpful
Glad to hear that! Please share :-)
Always brilliant and factual Robert. Thanks.
Much appreciated
My comment got deleted for some reason (probably because it had links in it), so here we go again:
Thank you for another great demonstration and adding the axle loads to the calculator.
Could you please also test the effects of TBM on stability and various ways to achieve it? There are studies showing that more TBM seems to make the trailer more stable, but none of them so far even tried to figure out WHY this is. There are some speculations, but not really any data, so I'd love to see someone do some proper testing.
The variables are:
1. Load distribution: This can be ruled out as previous testing has shown that putting the load further forwards does not really help anything.
2. Axle load/grip of the car: Some people say that the increased stability comes from the increased load on the car's rear axle. If you were to take a trailer with little to no TBM (let's say
Reject all three explanations, please. This myth that "a bit of TBM is good, so more = better" has to die. Look through my tow playlist for more.
l2sfbc.com/one-reason-why-add-more-towball-mass-isnt-always-the-right-answer/
@@L2SFBC I'm not saying that more TBM is always better - I actually believe the exact opposite, which is why I'm asking those questions (and why I was the one who suggested adding the axle loads to the calculator under the video about weight distribution). I may have worded the comment poorly because I didn't want to spend an hour re-typing what got deleted because of a link in the original comment, so let me try again:
I found a study called "*An experimental investigation of car-trailer high-speed stability*" from the University of Bath in the UK. This study found that
1. Adding TBM (or, as they call is "nose mass") from the original 5 % to 10 % improved the high-speed stability of the trailer and vice versa.
2. However, moving the load closer to the axle to reduce its inertia improved the stability *even more* than increasing the TBM, and
3. increasing the length of the tongue/nose of the trailer *also* brought significant improvements, although doing so *reduces* the TBM (since it's acting on a longer lever).
The above already suggests that even the widely-used "10-% rule" may not be true and less TBM on European-style trailers doesn't make them "inherently unstable" like I've seen some Americans claim.
But this is not really relevant to this particular video. The relevant part is this:
"It was found
that an increased nose mass improved the system stability, although the improvement becomes less significant when the nose mass rises above 6-7 per cent of the total weight. *This effect is thought to be caused by the increase in the car rear axle load associated with nose mass that increases the ability of the tyres to generate side forces that damp out the
oscillation. In addition, the increased nose mass
raises the tow ball friction, which in turn helps to damp out the oscillation.* However, it should be noted that there are limits on the maximum nose mass, partly as a result of structural strength issues
and partly because too much nose mass will reduce
the front axle load and worsen the handling performance of the vehicle."
I initially missed that, later in the study, they *did* actually try a friction coupler and it did help, which confirms that friction also plays a large role in stabilizing the trailer. Now that I'm looking at it, *it looks like the coupler was actually almost as effective as increasing the TBM from 6 % to 10.5 %* (zero-damping speed of a bit over 66 mph with the extra mass/weight vs. 66 with the coupler), which also answers my third question.
The only questions that have't been answered therefore are: How much do axle loads matter here? *What would happen if you were to completely remove the TBM and replace it by an equivalent amount of weight in the car, above (or in front of) its rear axle*, so that the rear-axle load would be the same but with no lifting of the front axle?
Good questions. I shall do more with them as there are a lot of 'it depends' in the true answer. But you're on the right lines. Note that friction devices reduce manoeuvrability.
Yes I'll do something on this subject soon. See my 2m view video on 7 weights for trailer stability for starters.
Awesome video. Very informative. Thank you.
Thanks, please share!
This is obvious to me, but not to many people, I would imagine. This is also why I want to fit air-helper springs to two of my tow wagons that I use mostly for longer distance and heavier towing. :-)
Not obvious to many people no. We are all wired uniquely.
Look into that a bit more. A lot of talk around air helper springs on heavily loaded dual cab utes and bending the chassis
@@snells-window We're not talking heavy loads for me with that vehicle. I'd only tow up to about 2000-2500kg or so, with it. It's just about the amount of gear I tend to have in the wagon's boot at the same time as tongue weight. They're both softly sprung cars, and both will be lowered sooner or later, one already is. I just want hte car to drive level and have some suspension travel for undulations in the road.
@@fredio54 remember that just like the distance of the towbar to the rear axle amplifies the TBM, the TBM can be multiplied significantly further when going through sharp high speed dips like you often find on fast dirt roads. From my understanding, fitting air springs can change the load/stress points to different parts of the chassis, at least in leaf sprung vehicles.
@@snells-window You're not wrong, however think about this: If I go through those same dips/bumps/braking zones/corners with the vehicle heavily laden and sagged badly then the amount of travel available to absorb those surface variations is minimal and the suspension will bottom out and the bump stops will incur a very strong force very early in the impact/compression cycle. This is worse than having sufficient spring rate (of any sort) to cope with the events that unfold.
good video with great information , thank you for the information
Thanks please share 👍
New to the channel but these videos are great!
I'd really like to see one addressing weight distribution hitches vs. air bags (or other supplemental suspension parts) that simply help maintain rear ride height.
Thanks Jack. I do have one on WDH, but not on airbags. I might do one on the merits of keeping the towcar rake as it should be as opposed to dragging the backside. Air suspension is great for this!!!
@@L2SFBC Well that's what I'm wondering🤔..
Does maintaining rear ride height (through stiffened susp) actually serve to adequately distribute weight to the front wheels, as a WD hitch would?
@@L2SFBC This is perhaps a better explanation of my question but it doesn't go into the depth that your videos tend to:
th-cam.com/video/XBZu39pQ8Gg/w-d-xo.html
Raising the rear from sagging to level has a tiny effect on weight distribution - a little more to the front. However...the height of the hitch also varies the towball mass, and it behaves opposite whether the trailer is tandem axle or single axle. Confusing hey? So, "it depends" I'm afraid. Raising the rear will never be as effective as a WDH.
Have you done any videos on A-frame flat towing of other vehicles? I'm expert in it, but I think you'd do a good job of explaining it to others. I do know, though, that it's not your area of interest nor that of your viewers, most likely. But perhaps it could be a nice little series to spice things up :-)
No I haven't and i have never A towed so I probably wouldn't. I like to focus on things I have practical experience with to back up the theory.
@@L2SFBC Fair enough. Crash course here and now, then:
1. Ball and hinge height should be very close to the same - if ball is lower braking causes compressed rear suspension and lightened front suspension like a ball weight - if ball is higher braking causes rear end jacking and increased front end weight - this can result in a sustained low-speed low-force oversteer condition in the tow vehicle (ask me how I know, ha ha)
2. Zero of the towed vehicle's weight is on the wheels of the car being towed and the towed car, unless it has a driver to assist with hills (up AND down if engine runs) the maximum decel G force is 50% if the weights are equal between tow and towed.
3. You cannot reverse easily and you cannot reverse at all without a helper in the towed car or the steering locked
4. Your steering must be free to move as needed when being towed forward - if a driver is inside the towed car they must only use brake/gas - they must not interfere with the steering wheel.
5. Cornering load from the front of the towed vehicle is applied to the rear of the tow vehicle
6. It's effectively the same as towing a trailer with a very long draw bar when moving forward - ie, the turning circle is very large and it's easy to accidentally cut corners and do damage (again, ask me how I know...)
7. If you DO have a driver then it's as if you have a double mass double power vehicle and the entire experience is seamless and easy
8. If you don't have a driver or the brakes are not working on the towed car then keep 2 in mind - it can get bad easily
9. If you're towing an auto and it won't be running and assisting then you must drop the driveshaft or CV axles or the auto will be destroyed by the act of towing because the oil pump is engine driven and key parts will not be lubricated.
I built mine to tow my race ute to the track years ago, but have since used it on a number of other vehicles to great success. They're a very nice way to go and especially if you can put a person in the back car to help slow it down (they brake when your brake lights show, they accelerate when they feel you do so and/or they see a hill or are coming out of an intersection or whatever. I prefer it to car-transporter use these days. You just have to know what you're getting into. Kinda like MIG locked diffs - they're great and ultimately predictable, but you have to know what you're doing when you drive one or it can get you into trouble. :-)
@@fredio54 I used to have an A frame on my little suzuki 4wd. Hook it up to another suzy offroad and you had 8 wheel drive!
@@snells-window Ha ha, yes indeed :-)
Excellent video. Fairly simple math. Do you have any work demonstrating effects of WDH on this situation? Would be of great interest to many caravaners.
Yes I have a video ob WDH
Very Interesting and excellent demonstration about how the single axle and tandem axle affect the towball mass, which led me to a question about Load Sharing Tandems.
Considering the towball mass, with a true load sharing tandem suspension compared to the the tandem model in your demonstration, which would mimic the independent coil systems on vans lately, (except for the Simplicity Axle LSC) would this have a different effect?. As these are designed to keep the same amount of weight on each axle within suspension travel limits, so would a Load Sharing Tandem setup, act similar to the single axle in regards to TBM?.
Yea it would I forgot mention that good point.
50/50 of 2740 tare is 1370kg so your sums are out by 50kg
Ooops yes...got by me and all checkers! However the principles remain the same.
My weight distribution/sway control hitch was installed by a professional. I took my truck & caravan to him for installation. Am I correct thinking he should have set all of this up properly? 👍😊
I'm sure he did!
Could you please do a simplified version of this video. I just felt most of this whooshing ove my head…
Sorry about that.
Simpler version - every 1 kilogram of towball mass means more than 1 kg added to the rear axle load. Don't exceed the rear axle load.
I tend to watch the videos a few times myself because a lot of it whooshes over my head first go round! 👍
I've come to understand that Tow Ball Weight can be too much, as well as too low. What would you say is the optimal weight on the ball? (I'm aware of wanting to keep the majority of the weight over the axle of the trailer for stability.)
@2.07 if you put more weight on the front even though the vehicle gvm would increase would it also decrease the rear weight and tranfer it to the front? Is it aboute keeping the vehicle sitting level to keep the weight ok or physical weight ay the front or rear to change it.?
By far the best trailer weight video on youtubes also.
great video, thanks for posting this. are you going to do another video explaining the same loads but with using weight distribution bars? ( it would be the next logical step) also have you noticed the 'long' tow ball hitches ( generally height adjustable versions) that add to the overhang? do you know of a height adjustable ( or weight distribution hitch unit) that is 'short' ? so your overhang is keep to a minimum? also how does load sharing dual axle trailer suspension act on down ball weight?
extended hitches ARE EVIL!!!
@@L2SFBC yes they are evil....... in most circumstances.
In my case, I have a Chevy Silverado with a GVM of 5,171kg and a GCM of 11,113kg.
The front/rear axle ratings are 2,359kg and 2,812kg respectively (hence the 5,171kg GVM).
I tow a 3,500kg Bushtracker caravan....so I'm well within the GCM.
However, because of the truck-like rear suspension (it barely budges when I add the 320kg ball weight), the ride when towing was less-than-pleasant.
The "fix" for that was to purchase a product called an Airsafe Hitch which gives an airbag cushion between the two vehicles.
Unfortunately, the trade-off is both weight (the Airsafe weighs around 35kg) and the increased distance from rear axle to pivot of around 300mm.
Fortunately, having such a long wheelbase in the first instance, these trade-offs are well-worth it and I wouldn't tow the van without the Airsafe Hitch.
That's fantastic information thank you and yes totally agree it depends!
Why not triple axle trailer???
It's more balance in any road condition, level and roads
Heavier, more expensive and harder to turn.
I dont trust manufacuer tow ratings . add 6 on board 2 dogs full tank of fuel
can you clarify point 5 at the end there - does raising/lowering towball height have less of an effect with single axle vans, or less of an effect with tandems?
Less effect with tandems and the effect is opposite to singles
If you do a 50/50 split on the front/rear axles isn't that 1370kg?. You've got 1320 which equates to 2640?
sorry error
Hi Robert. What is your views on WDH function of some weight transfer to front axle?
I would avoid WDHs unless necessary. They do add weight to the front axle and also the trailer axle. But they have complications. I'd prefer to get a bigger towcar. Also note quite a few manufacturers expressly forbid use of a WDH.
@@L2SFBC yes, just a band-aid for level roads and disconnected if going up a driveway into service station, spoon drain, bull dust holes, speed bumps and the like. I enjoy your spot on presentations and associated views. BTW it is a subject I enjoy but I don't tow with my Dmax, it is just a full time tourer build.
But that wouldn't be the same for load sharing tandem axles would it?
Load-sharing twin would act much like a single.
@@L2SFBC so there are no concerns with performance of the trailer not being parallel to the tow vehicle chassis, in terms of braking or stability, outside of the load distribution?
Ultimately I want it to be flat, but for instance we are about to put the trailer on my mates BT50 (I have a Hilux) and his ball is 60mm higher. Now we are only towing about 2000kg, so we aren't in the limit.
Trying to determine if we have to fork out the coin for an adjustable hitch for a 4400km trip or just send it.
How the TBM changes in case of Triaxle when the TBM is lifted up or downwards
quick question:
To calculate the total effect therefore on the rear axle, I'd need to include the vehicle payload weight. What'st the best way to do that?
Would I simply add the payload weight from the second row and the boot with the towball effect to complete this analysis for the total rear axle laod?
Thanks
Best get front and rear axle loads on a weighbridge
@@L2SFBC thanks for your reply!
Are there any rules of thumb that can be used to estimate?
I may do this for several vehicles I'm looking at purchasing
l2sfbc.com/towcalc/
Do you divide the overhang by the wheelbase or the wheelbase by the overhang, because my WB is 3062 and my overhang is about 920 +/- 10mm and doing the wb by the overhang give a 60kg @ over 199kgs, and thats just nuts, thanks.
l2sfbc.com/towcalc/
If you model trailer had a spring equalizer like most road going tandem axle trailers with leaf springs have, then you would find that the weight isn’t as sensitive to height as they equalize the load. If they have torsion axles that don’t use equalizers, then your explanation is dead on.