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Discussion Starter #1
My 1990 yj has, I think, 15x7 wheels on it now. One of the last things I will do to it is put on new wheels and tires. Since it is more sand and beach than rocks and trails, I will not be lifting it. I am trying to figure out a larger tire than the 235 75 15's on it now. I want to go both taller and wider on a set of 15x8 wheels.

Since this is just math, 235 is millimeters of tread width, and that works out to about 9.25 inches of tread width. 75 is the aspect ratio, so the bead to tread sidewall height should be about 6.9. 15 inch wheel, plus 6.9 x 2 equals a tire height of about 28.8.

Based on that, without lifting, I think 30's would be easy, the question is how wide can I go?

The math works out to about a 275 70 15 for a 30" tire, but they dont seem to make it. Am I better off going to a 16" wheel?
 

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You could shoot for a 30x10.5x15 tire instead of the metric. (at least I think they make a 30x10.5). It should fit ok on an 8" wheel.
 

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30x9.50x15 fits.. or you can cram a 31x10.15...
 

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Discussion Starter #5
A friend is trying to talk me into doing a 2" shackle lift before I get bigger tires. Another says if I do the lift, I will have to change something on the drive shaft or U joints because they will start snapping. From being on the wrong angles. Which would yall do.
 

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2" shackle lift should not strain anything nor would you need to change anything, you will not be putting any extra strain on U joints. My personal opinion is not to change the shackles like that, but there are plenty of others doing it with no hard effects. I have a 4" lift and 33" tires running with stock axles and ujoints with out any problems.

I would start with the tires and see how they fit and run. If you start rubbing or having issues there are ways around it including the shackle lift. You could do a body lift, or even just save your money and do a proper spring lift. (proper in my opinion that is) :)
 

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As a long time Florida jeep guy (who started w/ flat, stock suspension).....you can run a 31X10.5 w/out any problem for mild beach work.

They fit fine on a stock 15x7 rim, but will limit your tuning radius slightly. Trim the lip of your stock flares, or grab some off a TJ for way more room.
 

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As a long time Florida jeep guy (who started w/ flat, stock suspension).....you can run a 31X10.5 w/out any problem for mild beach work.

They fit fine on a stock 15x7 rim, but will limit your tuning radius slightly. Trim the lip of your stock flares, or grab some off a TJ for way more room.
exactly...if you are pretty much running on flat ground the 31's will be fine,I have run that setup on several..my wife has a 3 inch body lift on hers and runs 31's on 10 inch wheels..it looks great to me..as far as a suspension lift,you can go a couple of inches with no problems what so ever but the straighter your driveshaft angles are then the less your u joints have to work and the longer they will last..one good point for the body lift especially in the deep south is that it will keep your floorboards cooler because it puts more space between it and the exhaust and transmission
 
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