if running 35's how much will it effect towing CAPACITY? I am not worried about gearing, I understand i will have a harder time picking up. but would it be recommended to not mess the the full 3500 lbs. it is rated for?

 

If I'm reading your question correctly, the answer is it depends on the tire and wheel manufacturer. Both are load rated and will determine the absolute maximum you can carry.

But adding larger tires will increase the rolling resistance, decrease the mechanical advantage of the final drive gear ratio, and reduce braking effectiveness.

If you need maximum towing performance you've got the wrong vehicle.

 

There are a lot of other factors at work here.

What's the wind resistance of the trailer?

What's the terrain like?

Are you pulling into a headwind?

Do you have trailer brakes? Electric or surge? How good is your brake controller?

What's the tongue weight on the trailer?

How many axles does it have?



Long story short, I'd be tempted to knock 500 or 1000 pounds off the top of the "rating" if you're running a lifted Jeep with bigger wheels...but then again I'm pretty cautious when it comes to pulling trailers. I've seen too many bad things happen with trailers to be any other way.

 

thats what i was thinking, I am not looking for super towing ability, I just dont want to mess stuff up when I put on the larger tires.

anybody else?

 

Whats your gear ratio? Automatic? What do you plan on towing (pounds)?

 

JK's can tow more than the rated numbers (see the european JK specs...), so no issues there except the extra sluggishness from going larger. What I would worry about is the braking. Be sure you're set up correctly and that the trailer has good brakes.

 

Probably, but if you picture what kind of trouble you're in if you hit/kill/wreck someone with a overloaded vehicle, it keeps me from doing it. Euro specs don't apply here. People have been hit for manslaughter from a deadly accident from over-loading/towing a vehicle. Not something I would like to gamble with. It is not a tow vehicle. Just my opinion.

 

No, I wasn't suggesting anyone in the US tow more. Simply that the vehicle, on stock gears, is capable of it. So I would be more worried about stopping with bigger tires, than about pulling a load with bigger tires. (though I think a tranny cooler would be a very good idea, especially with stock gears)

 

Pulled a pop up camper to Ouray, Co. a few weeks ago from Iowa and back. 3.73 gears, 35's (KM2s), manual tranny. Once I hit the mountains I stopped for gas and a Colorado local who was following me up the pass complimented the Jeep on how well it did pulling the trailer. I am a pretty cautious driver giving myself plenty of room for whatever could happen and the Jeep never broke a sweat.

 

I tow a pop-up trailer with a dry weight of about 1800 pounds; loaded I am probably somewhere around 2700 lbs. I have a Rubicon with 4.10s rolling on 35"Procomp Xtreme MTs with a 3.5" lift. Prior to towing I installed an electric brake controller, a transmission cooler, and some air bags to keep it level. Back in July I towed the trailer to Zion in Utah from Sacramento and it was a bit of a white knuckle event due to tons of sway from passing big rigs and wind. When I got home I installed a sway control bar and it made a world of difference. I recently went on a fishing trip down to Convict Lake which involves going over several mountain passes of about 8500 feet and the sway bar improved the experience immensely. Granted going up hills the Jeep is a pig and it kicks down in second gear reving RPMS up in the 4000-5000 range. You just have to realize when you tow up long grades you are not going to be going very fast. A re gear to 5.13s would probably help. I have seen those European tow ratings and can't imagine where they got those from. With my current mods, the Jeep is an adequate, but not great tow vehicle. I will be towing my pop-up to Easter Jeep Safari come March 2010 A couple of pictures from my recent fishing trip.