How do you change rim/tire size parameter on an XCAL2?
06-15-2009, 09:10 PM
#1
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How do you change rim/tire size parameter on an XCAL2?
Went from my stock 17" rims to the GT500 rims and tires.
I'm sitting on 285/40/ZR18's in the back and 245/45/ZR18's in the front (I don't think this matters?), I believe.
I was thinking that it was relatively simple to change, but apparently not? What parameter do I change to account for the new rim/tire size?
I'm sitting on 285/40/ZR18's in the back and 245/45/ZR18's in the front (I don't think this matters?), I believe.
I was thinking that it was relatively simple to change, but apparently not? What parameter do I change to account for the new rim/tire size?
06-15-2009, 09:21 PM
#4
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http://www.bigcustomwheels.com/rt_specs.jsp
So looking at this, I went from 235/55/17's (at 742.8 revs/mile)
to 285/40/18's (at 748.2 revs/mile)
Yes, no?
So looking at this, I went from 235/55/17's (at 742.8 revs/mile)
to 285/40/18's (at 748.2 revs/mile)
Yes, no?
06-15-2009, 09:47 PM
#7
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Join Date: Nov 2007
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The only way to get the real numbers is to measure. If you don't want to calculate pi then measure the circumference instead and divide that number by 63360 (inches in a mile). Manufactures measure an unmounted tire. Things change when it's mounted and put on the car. For example my 255 45 18's are 759 revs per mile although BFG rates them at 769. Another example would be my 555r drag radials. Nitto says they are 811 revs per mile but they are really 790 when on my car.
Uh, I guess err on the side of caution and go with the higher number? At least then, when I'm speeding, I won't be speeding *as badly?*
How did you find the actual revs/per mile on your car?
