Another BFG R1 thread

Aaron Buckley · **Posted:** Wed Feb 09, 2011 3:07 pm

Graham Jagger wrote:

315s on a 8.5" rim?? Why? I get the feel good thing to a point. But for track or autocross. A tire that fat on a rim that skinny. I'd be curious about the contact patch and how much grip you truly get vs just mounting a 295 on said rim. I'm putting 315s on 10.5" rims and they say pretty square and I get full use of the tire at typical pressures. That is with Hoosier. Never used V710s or BFGs. Just seems like overkill and added expense. Does anyone have times on track or autocross to show good or bad?

i don't know about Bernie's situation, but when I was running the C6, we would kill a 295 up front in about 30 runs. By moving to the 315 up front, we could get over 90 runs. This was using a A6 Hoosier. The grip and turn in were nearly identical, it was just where the tire would wear seem to hold up better on the 315.

For the STi, while a 295 Hoosier is just as wide as a 305 V710, the V710 is much better with camber challenged cars like the STi (although they do get greasy with heat). If I could find someone who could get a 305 V710 on my 8.5" rims, I would try them. For this year, I have two identical lightweight sets of wheels, so we will be changing all 4 tires for each driver. - AB

Graham Jagger · **Joined:** Fri Aug 29, 2003 12:53 am **Posts:** 1718

Aaron Buckley wrote:

i don't know about Bernie's situation, but when I was running the C6, we would kill a 295 up front in about 30 runs. By moving to the 315 up front, we could get over 90 runs. This was using a A6 Hoosier. The grip and turn in were nearly identical, it was just where the tire would wear seem to hold up better on the 315. - AB

You were running a 295 on a 9.5" rim, not an 8.5" correct?

After 30 runs did your cord the outside edge, like as in about 1-2" in from the edge? Was the outside edge badly beveled? If so I could see how you moved the wear further in board. I would assume the heavily beveled outer edge was much less?

I haven't used them for AX but a couple of times. For track I notice putting 315s on 10.5" rims works well but not great. Even with almost 2.5deg of camber and poly bushings. The outside edge bevels hard. They have to be flipped fairly often to make them last. I even swap front left/right on the 2nd day to even out the wear. Not quite the same for AX since you can't guarantee how many left/right turns you'll make.

Aaron Buckley · **Posted:** Thu Feb 10, 2011 5:40 pm

Graham Jagger wrote:

You were running a 295 on a 9.5" rim, not an 8.5" correct?

After 30 runs did your cord the outside edge, like as in about 1-2" in from the edge? Was the outside edge badly beveled? If so I could see how you moved the wear further in board. I would assume the heavily beveled outer edge was much less?

I haven't used them for AX but a couple of times. For track I notice putting 315s on 10.5" rims works well but not great. Even with almost 2.5deg of camber and poly bushings. The outside edge bevels hard. They have to be flipped fairly often to make them last. I even swap front left/right on the 2nd day to even out the wear. Not quite the same for AX since you can't guarantee how many left/right turns you'll make.

It was an 8.5" rim, as the C6 non-Z06 is 18x8.5 front with 19x10 rears. The 30 run cord was on the edge and it did bevel. It was about 1/2" off of the sidewall. By mounting the 315, it move the wear area further from the edge and "rounded" the tire a bit, which didn't create the "bevel of death". This allowed the tire to wear much better. - AB

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