JKMARINE

Nobody has proclaimed to the smartest person on here. I would like to meet that person. Maybe I can learn something from them. It is just Jeeps but there is a science behind it. If someone on here said 2+2=5, pretty soon everyone on here would be posting that as fact. That's just the way it is. I guess you like it that way. Ignorance is bliss I suppose.

rsbmg

Got that fixed for you. I don't want any misinformation being spread. Pretty soon people will start believing that scientists designed the jeep. Crazy world.

JKMARINE

http://en.m.wikipedia.org/wiki/Science Glad you FIXED that for me. Engineering is a form of science, but you already knew that didn't you? I was just wondering if you could find some false information in my original post that provoked your remarks? Is it because I said The Dirtman was right and didn't mention you? I'm deeply sorry to hurt your feelings like that. I will praise you and your vast knowledge in every post from now on.

rsbmg

I'm very sensitive apology accepted.

sea bass

Jkmarine,
I get what you're saying - there's a trade off for mods such as lifts, tires,etc. you're saying that wider tires and more back space are not the cure for a bigger lift which I get. Even if you don't lift your jeep but want to make it capable and want to run bigger tires, less offset is a must. If the OP is wanting to run 35's and no lift ( my assumption) then it will require running spacers or less offset wheels - it's not a product is the lift, it's a product of running bigger tires to make a stock rig more capable. Your comment about running a lift and requiring a wider track isn't completely accurate.
What is your recommendation?
Please note - this is not meant as an attack :-)

MR LIKA

But if Eddie said it, then we know it's true.

JKMARINE

Ha ha

JKMARINE

Your Roll Center is a constant measurement for the JK and other solid axle vehicles. On the JK and Solid axles, it is at the center if the axle at the top of the tube. Your Center of Gravity is for the most part constant. It will change with a rack, tire pressure, armor weight, etc... As I mentioned, lifting the JK will separate your Roll Center and Center of Gravity. This makes your JK want to roll more because you raised the weight higher over the fulcrum. While you don't have to widen your track width if you don't want to, it helps to counteract the JK wanting to roll by having a wider base. The trade offs are premature wear of all suspension components because you are moving the wheels and tires further away from the stock location. The best way to correct this is an axle swap. Back to the OP.... If you wants to run 35s with no lift, he will need to have a lower backspace or run wheel spacers to not rub. Like I was saying, you will prematurely wear parts. He would need to figure out his Steering Scrub Radius for acceptable parts wear. The best way to do this is on a CAD program or making a scale drawing version of your axle, wheels, and tires.This requires accurate measurements of all parts. Most people don't know that their wheels aren't actually 17" or that their tires aren't actually 35s. You'll basically, make an imaginary line to bisect through your ball joints to the ground and one through the Vertical center of the tire. The distance between the 2 is the Scrub Radius. The optimal measurement for best road manners and parts wear is 3/4"-1" positive Scrub Radius (towards the inside of the tire). I recommend people read up on it. Its more in depth than that, but pretty easy to understand and apply.

JKMARINE

Here is a visual. Imagine a solid axle and not A-arms.

sea bass

I feel like we're saying the same thing - only you're saying it with more detail and facts :-)

As you increase tire height, you have to decrease backspace to maintain proper scrub radius also resulting in a wider track adding more stability. It has to be the proper ratio (or balance) in order not to have too much of a positive or negative scrub correct?

Yes - this adds stress to an already week stock bj as well as other components but that goes without saying. Nobody should expect to be able to add bigger tires without trade-off of worn parts that will likely need to be upgraded sooner than if left stock. We do it to increase offroad performance right? Short of replacing the entire axle as you stated, this is what we have to do.