Rear tire and wheel size

Discussion in 'Drag Racing' started by joshuaw3, Mar 2, 2015.

  1. joshuaw3

    joshuaw3 Active Member

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    So I want to go as wide as I can in the rear with drag radials for this upcoming season. I'm going to be buying some cheap summit brand wheels or something similar that is 15x10. So what offset should I be looking for on the wheels and subsequently what size radial could I run. I appreciate the help.
     
  2. mcglsr2

    mcglsr2 Well-Known Member SN95 Supporter

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    I don't specifically know the answer, but I can suggest to you how you can arrive at the answer. When sizing new wheels, I use this site: offset calculator. You can put in your stock (or current) wheel width and offset, and then start playing with new widths/offsets, and the calculator will tell you how much space you lose or gain on the inside as well as the outside - in millimeters. Armed with this information, go to your current wheel, and start measuring. See if you will hit anything on the suspension side (remember that the wheel rotates, so check all areas for clearance, not just the obvious ones), or if you will contact the wheel fender on the outside.

    Once you have a good idea of the size you think you think you want, post up asking if anyone runs that size wheel (your original question is a little too open/vague I think). People will either tell you they run it with no problems or there are fitment issues. Once you know the wheel will fit, then last step is to find the appropriate size tire to fit that wheel. And you should be good to go.

    Edit: having said all that, I know for a fact that people run 10" wide wheels in the back with no trouble. Try checking out American Muscle and Late Model Restoration and shop for 10" wide rear wheels - then look at the specs. They will list the offset (and backspacing). You can use this info to hone in on what you want for the calculator.
     
  3. joshuaw3

    joshuaw3 Active Member

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    I'm just trying to get a cheap set of rims from summit for drag but they are like a -39 offset they have a big lip. But a tire guy I talked too said that's a crazy offset if I haven't cut the axles to try and run 295 50 15s. So I'm trying to get an idea of what offset to look for so that I could run those tires. Hopefully that helps clear it up a little.
     
  4. Mustanger

    Mustanger Well-Known Member

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    I run 10.5" wheels from Stage3Motorsports with 315-17" and lowered 1.5" with no rubbing issues so like posted above check around for specs on backspacing etc on 10-10.5" rims & compare your 15x10's
     
  5. philly101

    philly101 Member

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    I run a 305 30 19 in rear with a 27 off set no rub
     
  6. mcglsr2

    mcglsr2 Well-Known Member SN95 Supporter

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    So, using the calculator like I suggested you should do, for the current wheel specs I used a 8" wheel with 30mm offset (got this info from American Muscle), and then put in your number of 10" width with 39mm offset (the lip doesn't matter, what matters is the offset). The calculator told me that you will have 34mm less space on the inside (the wheel moves 34mm closer to the inside suspension), and 16mm more on the outside, which means the wheel is 16mm closer to the fender. Will this fit your car? I don't know. Do you have that much room?

    For comparison, I looked at wheels on American Muscle and Late Model Restoration. They sell 10" wheels with an offset of 22mm, and 10.5" wheels with an offset of 28mm. Plugging both of these into the calculator, I get:
    • 10" wheel, 22mm offset: 17mm LESS space on the inside, and the wheel will extend 33mm closer to the fender
    • 10.5" wheel, 28mm offset: 30mm LESS space on the inside, and the wheel will extend 34mm closer to the fender

    Compare the above, which AM and LMR will pretty much guarantee they fit, to your wheel. So, it looks like your issue will be the wheel is too close on the inside. You can easily fit the extra 16mm extension towards the fender (as both wheels from the list extend more than that and fit), however your wheel is closer on the inside than the others. 4mm is the difference. 4mm is a very small gap, but that could easily put your wheel into contact with suspension. I honestly don't know.

    I think your best bet, if you want to run a 10" wheel and know for sure it fits, is to look for one with an offset around 22mm. If you want to adjust the wheel from there, then use 22mm as a baseline, If you want to push the wheel further away from the suspension and closer to the fender, then run a slghtly smaller offset, like 21mm or 20mm, etc.

    If you want to tuck the wheel into the wheel well more, move it closer to the suspension, then run a slightly larger offset, 23mm or 24mm, etc.
     
  7. sleepn_sn95

    sleepn_sn95 Well-Known Member

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    For a 15x10 you will want to run some where around a 5.5-6.5" bs. Normally drag wheels just advertise by their bs and not offset. As for tire size a lot of people run 275/50/15's.

    Just do some searching here and over on corral. Tons of people run drag setups on their sn95
     
  8. joshuaw3

    joshuaw3 Active Member

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    Bs?
     
  9. sleepn_sn95

    sleepn_sn95 Well-Known Member

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    back space