Tow ball projection beyond back axle.

never found it to be a problem as long as it dont rip your knee cap off when passin

11/60 wrote: Hi, I need to get my head round the dynamic effects of the projection of the tow ball beyond the back axle as related to driveability of the combo. If for argument the car and trailer are identical each time and the rig rides level with a suitable nose weight and balanced load, as I understand it with a short distance from the axle to the ball the apparent vertical load on the axle is reduced because of the shorter lever action thus the front axle is not being unweighted as much and vice versa for a longer tow ball projection the rear experiences more load and the front gets lighter and stability is reduced. Correct? When applied to cornering the same longer lever action is equally unsettling on the car as the trailer tries to push on against the turning car. Obviously there's a lot of physics at play here but generally the shorter the rearwards projection of the tow ball the more stable the rig?

Don’t know if this helps but...

I used to have a merc van, which had a huge distance from axle to towball, and that would go light on the steering with a heavy trailer on. Newer van is a Renault with much less distance to back axle, and that tows much better with the same trailer and cargo (2 ton scissor lift).



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Your assumptions are correct.

Whether there would be a problem would depend on how extreme your "theoretical" rearward extension is. Even assuming you are looking at a maximum nose weight (I believe about 130 - 190 lbs for a Jimny) I'm not sure there would be significant impact unless the extension is extreme. That nose weight range is probably close to the weight of most members of the forum. Unfortunately I lean toward the upper end of that. If you can imagine the effects of standing on the tow ball at the different locations, that is close to the effect your shift would be. The biggest impact to handling would likely be if the tow ball was moved rearward significantly and you were driving on an uneven surface. The vertical force at the tow ball would include some g loading in that scenario.

I clarified my post too late. Sorry I didn't catch it before your reply.

Spot on. The rear wheels are the fulcrum. Longer lever=more force. I'm not sure if some Jimny towbars are better than others in this regard?

An accident waiting to happen.

Well there's your problem.

Sorry....couldn't help myself.

If the difference between the measurement from the rear axle and the stock/original tow ball location to the new extended location is a 15% increase, then your math is correct. I also agree to your comment about how the increase relates to the Jimny. Not only vehicle weight but due to the effects of a short wheel base.

I don't know all of the issues you are trying to understand or resolve. If there are issues with how your Jimny handles while towing, I would ask under what conditions. If there are issues, does it include while you are driving on a level paved road?

As I commented in my last post, If you are driving on uneven surfaces (bumpy farm land) you will experience transient loads where the forces will be accelerated. I made that comment in relation to a trailer load that was static. Something like carrying cargo. Carrying livestock where the mass shifts would be a nightmare of a calculation. If there are handling issues, and they occur on smooth level surfaces, the shifting mass may be the primary issue.

Oh.....and Merry Christmas.

Helijohn beat me to the punch in the lounge