7" and 9" r25 tire

[donotello10]

I know most everyone has switched to the smaller width FC wheels due to not enough heat generated with the 7"/9" widths. I'm thinking of trying R25 compound with the original 7/9 format. Has anyone tried this combo to increase tire temps? I realize with more grip camber settings, roll stiffness, and tire pressures may need to be adjusted.
Worth trying?

Len

[jchracer]

Others can chime in but I think most are running the 7 and 9 wheels. Some are running 8 and 10's which are allowed as well. I usually run the 7 and 8 tires on 7 and 9 wheels. I think the FC wheels are 6 and 8....No?

[ghickman]

Joel is 100% correct. The FB's run 7 & 9 inch, this is not a FC width. We once ran 8 & 10 but not long after everyone figured out that the tires simply never got hot enough.

Some have tried or use the 6 & 8 combo but most feel it isn't the fast setup.

I personally prefer the R25 compound all the time, I get a ridiculous number of heat cycles out of them and I'm pretty certain this is the case with most of the guys at the pointy end of the FB grid.

[Saracen]

Gary which Hoosier tire sizes are you running on the 7 front and 9 inch rear.

[ghickman]

Gary which Hoosier tire sizes are you running on the 7 front and 9 inch rear.

Hoosier lists these as FC tires but I doubt they're being used for that purpose, I could be wrong though.

20.5 x 7 x 13 front

22 x 9 x 13 rear

Back in the infancy of FB 2008-09 we ran the 8 / 10 and could never get them above like 140 degrees...not good for stick but they'd last forever.

FB's are easy on tires, so much so that I started the Runoffs last year on a 2 cycle old set of tires. And that wasn't because I was too cheap to buy new, I just like the way they grip at 2 heat cycles.

[10rmotor]

Those are also used on DSR/P2 cars. I use the 20 X 7.5 and 20 X 9 on my DSRs. The 7.5 front is really an 8" tire. Its called a 7.5 to differentiate it from the 20 X 8 which is a cantilever tire used on small bore production cars and a totally different construction.