I am getting my JK re-enginered to have a greater payload capacity and also a heavier tow ball weight.

What the engineer needs to know (and I need your help with) are the following items. Please note that the answers have to be 100% correct for me to give to the engineer, so if you are a little unsure please don't answer.

Please note that I have an 07 Rubicon Unlimited.

1) Gross Vehicle Weight
2) Gross Combination Weight
3) Rated towball weight
4) Manufacturors weight rating for each axle
5) Wheelbase dimension

Thanks Heaps!!

 

All that stuff is in your owner's manual, or on the sticker on the B pillar. That information will be 100% correct. He should know that.

So, is the engineer going to make your Jeep rated to tow above 3500 lbs, or carry more weight?
Ask him if he will accept the responsibility if you are towing/carrying beyond the manufacturer's rating, and you have an accident. Lawyers would love to prosecute a case like that.
He may be an engineer, but I'll bet he doesn't know what he's getting into.

 

I have read my owners manual from front to back and it mentions everything I need under the towing section, but doesn't list any of the weights!!

The only stickers I have on my jeep are the Tyre Pressure one, the VIN and Build date one (with no other info on it apart from those two) and the warning stickers on the sun visors!!!

These guys are automotive engineers and it is their job to assess vehicles based on their modifications for higher ratings. They come with a certificate and therefore covers your insurance for towing/ carrying heavier loads.

 

That sounds good. Keep us posted. The axle rating on mine (US) may be different from yours (AU). But, I'll look anyway, if you want.

My US Rubicon Unlimited axles are rated as follows:

GAWR Front---2350 lbs.
GAWR Rear---3200 lbs.

This is in the US manuals:

VEHICLE LOADING
Certification Label
As required by National Highway Traffic Safety Administration
Regulations, your vehicle has a certification
label affixed to the driver’s side door or pillar.
This label contains the month and year of manufacture,
Gross VehicleWeight Rating (GVWR), Gross AxleWeight
Rating (GAWR) front and rear, and Vehicle Identification

 

Hey ronjenx,

Thanks for that. I wonder why the axles have a different weighting - considering they are the same axles - both Dana 44's???

 

First thing that cones to mind is the rear axle tubes are thicker walled.
Second thing is the rear springs may be stronger.
Third thing may be the front has ball joints/steering knuckle (weak point?).

 

Ask your engineer buddy why European JK's (both gas and diesel) are rated to tow double the weight of U.S. JK's.

 

Probably because in EU the lawyer/population is like 1 to 100,000 while in the US it is like 1/1,000!