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#1
10-25-2016, 09:56 PM
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Going from 15x7 to 15x8 rally wheels
I am currently running a set of stock 15x7 pontiac rally wheels. The center caps and trim rings are immaculate ando I have a brand new set of Cooper Cobra 255/60/15s mounted to them. If I went with 15x8s, would the extra inch of width reduce the tire diameter? Could I reuse my trim rings? My tires measure 26" in diameter right now. I would eventually mount 295/50/16s on the back.
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1970 GTO: Atoll Blue, TH400, 400 +.060, small chamber Ferrea big valve fitted # 15 heads, Summit 2802 cam, Iron intake, Cliff Ruffles 850 cfm qjet, Hooker headers, 2.5 mandrel bent exhaust, Race Pro mufflers, 3.73 Safe-T-Track. |
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#2
10-26-2016, 12:28 AM
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I run a 295/50-15 on the rear of my car & they seem ok, I have the 8" snowflakes & with even the 8" rims it would be better to go with a wider rim still as the tires seem to bulge a bit. I think it would be better to run a 10" wide rim with a 295/50.
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#3
10-26-2016, 06:39 AM
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It's all about the backspacing as far as the trim ring fitment.
If the 15x8's have .5" more BS, the trim rings will fit exactly the same. If the BS is different it will affect the fitment. The difference in tire height will be extremely minimal - a tenth of an inch at most. I agree with Rex, a 295/50/15 does not belong on an 8" wide rim. |
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#4
10-26-2016, 11:32 AM
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I have looked at some 15x10 Pontiac rally wheels and they look great. Do you think that a 295 tire on a 10" wide rim would have the same diameter as the 255s on 7" wide rimselection on the front? The measure 26" in diameter.
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1970 GTO: Atoll Blue, TH400, 400 +.060, small chamber Ferrea big valve fitted # 15 heads, Summit 2802 cam, Iron intake, Cliff Ruffles 850 cfm qjet, Hooker headers, 2.5 mandrel bent exhaust, Race Pro mufflers, 3.73 Safe-T-Track. |
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#5
10-26-2016, 03:52 PM
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I don't know how you're measuring the diameter of your 255/60's, but they are 27" tall.
A 295/50/15 is 26.7" tall. The diameter of the tire is basically determined by the steel belts, so there is very little, it any, change in diameter between rims of varying widths. What will change is the section width of the tire. The rule of thumb is that for every .5" extra rim width the section width will increase by .2". |
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