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Old 01-21-2009, 12:07 PM   #1
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Is this a bad idea?

I put 315/75/R16 wheels on my 0" lifted jeep. It fit perfectly in the wheel well and even has plenty of space for flex. I can spin the wheel both ways and it hits nothing. Why do people say I need a lift if I'm just going to drive on the streets for now?

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Old 01-21-2009, 06:07 PM   #2
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I looked here to verify what the numbers mean. A stock JK tire that I found on this site shows SBRP255/70R18 as a stock tire. The diameter of the stock tire on a JK is as follows:
Sidewall height: 70% of 255mm = 178.5mm /25.4 mm/inch = 7"
Total diameter of tire = 18" + 2 X Sidewall height of 7" = 32"
Tire width = 255mm / 25.4mm/inch = 10"
Rim width = 7.5"

The diameter of your tire 315/75/R16 is:
Sidewall height: 75% of 315mm = 236.25mm / 25.4 mm/inch = 9.3"
Total diameter of tire = 16" + 2 X Sidewall height of 9.3 = 34.6"
Tire width = 315mm / 25.4mm/inch = 12.4"
Your Rim Width?

The important information would be the manufacturer's maximum limits on tire size given your rim size. If those limits are exceeded and problems occur, then warranty could be effected.

The width of the tire if placed on the stock rim, will it work? If wider rims are purchased, can they be legally run on your vehicle? Some states have limits on how much the tire sticks out from the vehicle. I have heard from people that tickets can be issued if the tires stick out too far but don't know how this is determined.

I would think a tire sales place may have some handle on this. Maybe some people can post on the subject and bring it into better focus.

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Old 01-21-2009, 10:49 PM   #3
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My wheel is a 16x8. It's not very wide and it doesn't stick out much at all.
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Old 01-27-2009, 09:54 AM   #4
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Bud, I'm pretty sure your stock 16" steelies were only 7" wide... in that case that tire will not fit your rim. The largest tire I've found for a stock 16x7 steel wheel is the ProComp AT in 285/75/r16. That said, a 34X12.5 and no lift is going to rub offroad... and maybe even on road. Also the 6" of backspace on the factory wheel is not enough. You will need about 4" of backspace or wheel spacers or your front tires will hit when turning and rear when flexing. You be knocking off your flares man! ;O)

IMO, yes, it's a bad idea. If your set on a 34" tire you'll need new rims and a spacer lift, at minimum.
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Old 01-27-2009, 12:09 PM   #5
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Quote:
Originally Posted by scottrock View Post
Bud, I'm pretty sure your stock 16" steelies were only 7" wide... in that case that tire will not fit your rim. The largest tire I've found for a stock 16x7 steel wheel is the ProComp AT in 285/75/r16. That said, a 34X12.5 and no lift is going to rub offroad... and maybe even on road. Also the 6" of backspace on the factory wheel is not enough. You will need about 4" of backspace or wheel spacers or your front tires will hit when turning and rear when flexing. You be knocking off your flares man! ;O)

IMO, yes, it's a bad idea. If your set on a 34" tire you'll need new rims and a spacer lift, at minimum.
Ditto.

If your wheels are stock, they the tire is too wide for the wheel and won't seat correctly ---- could lead to premature wear at the least, catastrophic failure at the worst.
A 34 will hit the fenders at full-stuff without a lift; you could get away with a 33 if you don't disconnect the swaybar.
And without aftermarket wheels and correct backspacing you'll rub those tires on suspension pieces and put a hole in the sidewall.
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