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I'm confused on selecting the right size tires for the rims I plan on getting

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Old Sep 4, 2014 | 04:15 PM
  #1  
ak2012jkdude's Avatar
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Default I'm confused on selecting the right size tires for the rims I plan on getting

I tried doing research on backspacing and tire sizes and all the details that go into tires and wheels selection, but I only got a headache in the end LOL!

I'm wanting to get the Pro Comp 7069s for my 2012 two-door JK and was told I would have to get tires that are at least 12.5" wide because the rims are 9" wide.

Robot Check

I know I want to get 33" tires and was wondering what the correct size (in metric) I would need if I'm running a 2.5" lift and stock fenders.

Would I need wheel spacers to run this setup?

I do apologize as I'm still a noob to all this stuff so please bear with me LOL!

Thank You in advance!
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Old Sep 4, 2014 | 04:39 PM
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Well ill tell you what I have and I have no rubbing at all.

33×12.50×15 tires on 10 inch wide rims with 4 inch back space.

Lift is 2-3/4 rear
2-1/4 front
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Old Sep 4, 2014 | 05:31 PM
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There is some info in the FAQ's thread stuck right to the top of this modified area.

With a 2.5" lift, you can 35's. If you want to run flat flares and bumpstops, you can run 37's.

For the rims themselves, you want to look at the backpace/offset (how far in or out of the wheelwell the tire/rim sits.) I find backspace to be a much more convenient number to use. Stock rims are around 6.25" backspace. As that number goes down, the rim/tire move further out. A typical recommendation for a 35/12.50 is a 4.5" backspace, or 1.75" further out than stock. There are differences in both height and width in tires from different mfg's, so there is no one-size-fits-all answer for what the best backspace is. It is what is best for 'your' specific setup.

For rim widths, start by looking at the specs for the specific tire you want. The mfg will have a recommended rim width in there with all of the other information. Some shops will not mount a wide tire on a rim that is narrower than that recommendation. Others will. Many people are running 12.50" or wider tires on the stock 7" (?) rims without issue.

So, decide on the size tire you want. Decide on the rim backspace that will put those tires far enough out to clear everything inside the wheel well. Then find a tire shop that will mount the tire on the rim you select.

And if you choose to use the stock rims, then yes, you will want wheel spacers to move the tires out. Go for the Spidertrax type spacers with two sets of lugs, not the thin ones that sandwich between. I suppose you would also want them if you buy new rims with the wrong backspace...

Last edited by nthinuf; Sep 4, 2014 at 05:36 PM.
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Old Sep 4, 2014 | 08:11 PM
  #4  
Rob 12B1P's Avatar
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Why do you need metric sizing? Just get a set of 33x12.5 R17 tires. Closest metric width is gonna be a 315 but Im not sure which ratio would get you closest to 33". 315 75 R17 are like 34.5" tall IIRC.
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Old Sep 4, 2014 | 08:15 PM
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3.75 back spacing should do just fine and im running 13.50's
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Old Sep 5, 2014 | 06:01 AM
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Originally Posted by ak2012jkdude
I tried doing research on backspacing and tire sizes and all the details that go into tires and wheels selection, but I only got a headache in the end LOL!

I'm wanting to get the Pro Comp 7069s for my 2012 two-door JK and was told I would have to get tires that are at least 12.5" wide because the rims are 9" wide.

Robot Check

I know I want to get 33" tires and was wondering what the correct size (in metric) I would need if I'm running a 2.5" lift and stock fenders.

Would I need wheel spacers to run this setup?

I do apologize as I'm still a noob to all this stuff so please bear with me LOL!

Thank You in advance!
im not sure what the closest size is in a 17 but if you decided to go with a 16" wheel the closest size I could find to a 33/12.50 was 305/70/16 which is supposed to measure 32.81/12.01 but on my jeep I just measured them at about 12.25/11.5 on a stock 16" wheel
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Old Sep 5, 2014 | 06:08 AM
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If you look at the tire manufactures web sites or tire rack.com it will list the proper size of wheel width for that tire and will give you all the dimensions you need. On a 9" wide wheel with a 0mm offset you would be at a 4.5" BS that is good enough for around a 36"x12.5" tire and would not require wheel spacers for fitment. without rubbing. 14mm=1/2" if you have some offset other then 0 and would not run over a 5" bs on a 12.5" wide tire.
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Old Sep 5, 2014 | 06:50 AM
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305/65r17 is the metric size for 33X12.50r17 and as already said, the 17X9 procomp wheels have 4.5 inch backspacing which you won't need spacers or get any rubbing.
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Old Sep 7, 2014 | 07:12 PM
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Originally Posted by Da10A
305/65r17 is the metric size for 33X12.50r17 and as already said, the 17X9 procomp wheels have 4.5 inch backspacing which you won't need spacers or get any rubbing.
The 305s are 12" wide. Seems 315 width are 12.5" wide.

With a large 32" tire to true 33" tall, when mounted, you WILL rub if you disconnect with only 2" of lift and likely have some minimal rub with 2.5" with factory flares and factory bumpstops.

Sent from some string and a few tin cans.
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Old Sep 8, 2014 | 04:32 AM
  #10  
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I have 305/70/16's on no lift on stock wheel with 1.5" spacers and the only place they rub is on the wannabe skid plate even at full stuff
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