20mm difference: BFG vs Michelin
06-25-2019, 05:06 AM
#2
Sr.Random input generator
IIRC, you should have them both mounted (or unmounted, though less desirable). Otherwise, the numbers might get misleading.
06-25-2019, 08:46 AM
#4
Melting Slicks
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Your 305’s are slightly stretched, as you can see the side wall is at an angle where the 325’s are not. It will work, but you lost some contact patch.
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smitty2919 (06-26-2019)
06-25-2019, 11:06 PM
#6
You can easily see 10+ mm of lost contact patch on the bfgs on this side. So 20 mm total. So it's exactly as it states.
06-26-2019, 03:16 AM
#7
The extra width of the 305 is coming from the wheel pushing the sidewall outward. For an apples-to-apples comparison, I think you'd need to either...
a) mount the 325 on a 13" wheel. That might push its sidewall out an extra 10mm or so
b) un-mount the 305 so the wheel doesn't move beads (and thus the sidewalls) so far outward
For reference, Spec Corvette runs 315s on 10.5" wheels. You've got a nominally-narrower tire (305) on a definitely-inch-and-a-half-wider wheel (12"). So naturally the tire looks extra wide.
a) mount the 325 on a 13" wheel. That might push its sidewall out an extra 10mm or so
b) un-mount the 305 so the wheel doesn't move beads (and thus the sidewalls) so far outward
For reference, Spec Corvette runs 315s on 10.5" wheels. You've got a nominally-narrower tire (305) on a definitely-inch-and-a-half-wider wheel (12"). So naturally the tire looks extra wide.
Last edited by NSFW; 06-26-2019 at 03:40 AM. Reason: there was an inch missing
06-26-2019, 03:25 AM
#8
Sr.Random input generator
The extra width of the 305 is coming from the wheel pushing the sidewall outward. For an apples-to-apples comparison, I think you'd need to either...
a) mount the 325 on a 13" wheel. That might push its sidewall out an extra 10mm or so
b) un-mount the 305 so the wheel doesn't move beads (and thus the sidewalls) so far outward
For reference, Spec Corvette runs 315s on 10.5" wheels. You've got a nominally-narrower tire (305) on a definitely-and-a-half-wider wheel (12"). So naturally the tire looks extra wide.
a) mount the 325 on a 13" wheel. That might push its sidewall out an extra 10mm or so
b) un-mount the 305 so the wheel doesn't move beads (and thus the sidewalls) so far outward
For reference, Spec Corvette runs 315s on 10.5" wheels. You've got a nominally-narrower tire (305) on a definitely-and-a-half-wider wheel (12"). So naturally the tire looks extra wide.
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NSFW (06-26-2019)
06-26-2019, 03:32 PM
#9
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I just did it as a comparison now that the rival-s is offered in 19" sizes. Porsche runs 305s on 12" wide wheels for the gt cars, so I was curious as how much difference there would be.
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NSFW (06-26-2019)
06-26-2019, 03:59 PM
#10
Drifting
The width of the rim will influence the width of the tire. A tire mounted on a narrow rim would be "narrower" than if the same size tire was mounted on a wide rim.
Note: Because the overall diameter of a steel-belted radial is essentially determined by the steel belts, there is little, if any, change to the overall diameter of the tire due to differences in rim width.
The industry rule of thumb is that for every 1/2" change in rim width, the tire's section width will correspondingly change by approximately 2/10".
Note: Because the overall diameter of a steel-belted radial is essentially determined by the steel belts, there is little, if any, change to the overall diameter of the tire due to differences in rim width.
The industry rule of thumb is that for every 1/2" change in rim width, the tire's section width will correspondingly change by approximately 2/10".