Long story short I am seriously considering keeping my AP1 and running it in BS autocross for 2013. I have been reading all the old stock topics but I wanted to put my specific question out there.

Square is the route I would like to go ideally for reasons of rotation ability during flips (even wear out of the tires) and I can get more rubber on the ground that way. Most of the reading I see for AP1 square is the 245/45/16 and that looks like it has pretty much been all Hoosier. The newer BFG R1-S is now also offering this size and is very tempting to try but there could be issues.

Looks like the rear may be good to go but the fronts might have rubbing issues. Reading some old posts I see that the 245 Hoosier may rub the fender liners (inside?) and this could be worse with the BFG. Tirerack specs are what I have been looking at and the BFG is listed as wider still than the equivalent Hoosier.

245/45/16 Hoosier:

Tread width- 9.2"
Section width- 10.1"
Overall Diameter- 24.7"

245/45/16 BFG R1-S:

Tread width- 9.5"
Section width- 9.6"
Overall diameter- 24.7"

Note that the section width is actually less on the BFG but the tread width is wider. Both tires have the same overall diameter.

Any feedback on how big of an issue the rubbing is on the Hoosiers? Would the BFG be too much to realistically run? Has anyone tried these tires yet in this size? I should add this would be mostly local stuff with a handful of regional/national events. If you have AP2 experience feel free to speak up as well.

Thanks for any help guys!

 

IMHO, sidewall stiffness is the biggest issue. When I tried Goodyear 245s on the front of a CR, they rubbed worse than an A6 275 because of the sidewall flex.

 

I didn't notice any rubbing at all while running 245/45R16 A6s on my AP1. I suppose it could happen, but I wouldn't worry about it.

 

But would you risk trying a brand new set of BFG's in 245/45R16 knowing they run wider tread width?

Another question, how many runs did you get out of your A6's? rotate/flip?

 

Yeah, I should elaborate -- given that I didn't see any meaningful fender rub with the Hoosiers, I'd feel pretty comfortable trying the BFGs even if they are a little wider.

For comparison's sake -- you can have visible fender liner wear after a single session running 275s on the front of a CR. Even if the 245 BFGs rub more than the 245 A6s on an AP1, I'd be shocked if it was anywhere near the wear that CRs experience. And at the end of the day, fender liners aren't very expensive.

I only went through one set of A6s on my AP1, but it was amazingly short-lived. We wore the grooves off of the rears after less than fifty runs -- we were on track to cord them in sixty runs or so. The fronts did a bit better, but not much. I don't get the impression that others see this much wear, but I didn't have a chance to confirm; I sold my AP1 and bought a CR shortly after.

 

This is pretty close to the life I get out of a set of Hoosiers on my AP1. 80 runs is doable if you flip them front to rear around the 40 mark.

I'm still on original fender liners on my AP1 after about 4 sets of 245 Hoosiers, and that's with OEM shocks so I get a bit more body roll than most. There is some visible wear and I do replace the fasteners a couple times a year, but it's nothing compared to how CRs gobble up liners. I wouldn't hesitate to try a set of BFGs.

 

Thanks guys!

BFG does a rebate for SCCA members on 4 tires before the end of the year so that is pushing me to decide soon. Any other stock guys feel free to post your own tire experiences.

 

Yup, I got the same results as Jeff did. I did put on extended studs on the fronts and used a 5mm (or was it .25") spacer, tho. I replaced several fasteners... enough where I bought several in bulk and kept 'em in inventory for just in case.

If they moved the CR to AS, I would consider bringing back one of my AP1's to be a Stock class car. I must admit that I miss the A6 grip!

-Dave

 

^ no reason in moving backwards, move forwards to BSP

Stock class is pretty fun since you take out most of the tuning and just focus on the driving aspect

 

Tell the SAC, Dave!!! I talked to one of them at Nationals this year, and they don't think enough people like you and me exist.