275/40/17 Kumho V710's on an 8" rim???

[steverife]

Did any of the folks that went to nationals happen to walk by Dave Schotz's car? If so, were the tires noticeably oversized for the wheel?

Dave is/was obviously very fast, but he also ran 45-47 psi up front. How bad would a relatively inexperienced driver like me chew up a good 275 wide tire on an 8" rim? He runs his on aftermarket Bogarts racing wheels (factory offset), I'd run mine on OEM wheels. Would that make a difference as far as tire size is concerned?

If you are asking why an 8" rim, I have found myself motivated to halfway set up my car for F Stock.

[scottgib]

Take a look at Kenst's CRX tires/wheels at the next event.

Get Ted Visher into this question.

[MARKP]

I didn't notice the tires looking particularly oversized on his car. He is running a Cobra Mustang with the shaker hood scoop. I would be surprised if that car has the same wheel size as yours.

There are several reasons why Andy's car can get away with that wide tire on a narrow wheel. The biggest reason is the tire has a 50 series sidewall which is very tall according to today's autocross standards. I have seen several attempts to use the 45 series tire on a narrow wheel and it doesn't work. You end up bowing the tread area too much. Also, Andy's car is very light and doesn't really abuse the tires. It is also very well setup for the combination that is on the car.

All that said, the wide tire might work fine on your car. You just have to try it and see what happens. Everyone thought Robert was stupid for trying that combination and many people didn't have a problem telling him so. Those people ended up running that combination later on.

Lots of new ideas end up being called stupid at some point. It's not stupid if it works.

[steverife]

Schotz drives a Mach 1, which comes with an n/a 4.6 liter DOHC, a stick axle, and 17x8 wheels. I asked him about tire sizes on SCCAForums and he verified that he was was running 275/40's on his 8's and recommended that I do the same. A concern of mine, that I'm sure is a non-issue to Schotz, is tire wear and longevity.

I suppose the smart thing to do would be to swap my 275/40 Victoracers onto my street wheels and my OEM tires onto my autocross wheels (Hate to admit it but Bolton suggested this to me a while back and I shrugged it off. On the other hand -- Tony, check out Schotz's tire pressures. ) That way if I do roast a set, I'll roast a used set of Victoracers instead of a new set of V710's.

[thrdeye]

eh, I would say that unless you are trying to get FTD or something just go with something that you know will fit. There's no one in FS in our region really. I don't know if you are planning on a divisional or anyting though.

[MARKP]

I suppose the smart thing to do would be to swap my 275/40 Victoracers onto my street wheels and my OEM tires onto my autocross wheels... That way if I do roast a set, I'll roast a used set of Victoracers instead of a new set of V710's.

Sounds like a plan to me!

[TonyBolton]

Autox rims that are smaller than your daily driver rims=teh gH3yN3$$!

[tnturbo]

Don't you daily drive with 315s on the rear yourself

[TonyBolton]

Don't you daily drive with 315s on the rear yourself

Yes, and it makes absolutely no sense.........hence the FOR SALE post in the F/S section.

315's all around for next season OR BUST!

[tnturbo]

I would give it a try. I run 275/50 series BFG drag radials on 8" rims with no funky wear. I see quite a few people running 275/40s on 8s on the street. If you are buying those rims Bob has, one of them already has a 275 of some sort on it.

[steverife]

Tony's got no love for F Stock.

Thought of another option on the other end of the spectrum -- 245/40/17 Ecsta V700's. I'd be giving up some grip, but I'd be picking up some gearing and saving $120 a set over the V710's.

[thrdeye]

Gaining some gearing is more important than the litlle bit of grip you'd be losing, based on our thread about the falken fk-451

[MARKP]

I'd go for the grip over the gearing. If you were running a turbo, that might be a different story but you have the V8 stump pulling torque. The slightly larger diameter tire shouldn't be a problem with the V8.

[TedV]

Air pressure affects the stability of the tire carcass, and the tire spring rate. Higher means more rigid/stable carcass and a higher tire spring rate. I know more about the road racing applications on a mustang. In American Sedan, they are limited to a factory 16x8 rim. Most run a 275/45-16 or 255/50-16 depending on gearing/fitment issues. If Dave is up front going fast and recommends a setup I would listen to him, unless he is the type to tell the competition something wrong to screw them up and keep them slow. Copy what works, then adjust from there. If he is running a 17x8 rim with the same offset/dimensions as your stock rim, he has an advantage on unsprung, rotational weight. Tire wear should be similar. Shocks might be overworked with a heavier combo. The tire wear issue that comes to my mind is how much does the stock car push???? Pushing will cheese grate them in a heart beat. Showed that on Jeff’s car pretty quick at Taylor White. What can you do to remedy that? 275 on front, 245 out back?? Like Mark said, it’s not stupid if it works. Isn’t that part of the fun, trying all kinds of stupid stuff and see what it does?

I’d roast used stuff before I spent the money roasting new stuff. But then I am a low bucks, cheap SOB. If you have money to burn, by all means roast new and help the economy.

[XThree]

Hello, this is my first post here. I'm an autox n00b. Guess I'll ask myu first newbie question would bfgoodrich drag radial be good for auto x? I wan't something good for street, respectable drag, and autox

thanks