Rain tires illegal due to width

[Bob Coury]

Purchased rains with 9" rears a few years ago. Used one session, and kept in black bags. To my horror, I find out that the rears are now illegal as they are now too wide.

Anybody know why the rules changed to 8" width?

Thanks
Bob

[Lee Johnson]

Purchased rains with 9" rears a few years ago. Used one session, and kept in black bags. To my horror, I find out that the rears are now illegal as they are now too wide.

Anybody know why the rules changed to 8" width?

Thanks
Bob

Bob --

Are you referring to the wheel rim width or the rubber tire width as being a problem with the rains you have?

I don't think there was a wheel width spec change. As I recall, FC (FContinental/F2000) have had wheel width specs of 6 inch front, 8 inch rear well back into the 1990s (same as S2000 wheel sizes). Perhaps the older FC (1100cc, Cosworth BDJ engines, etc.) allowed wider (or narrower) wheels (maybe even without a spec limit on width).

If wheel width is your concern, remember that is measured at the inside where the tire bead seats, i.e., not over the lip of the metal wheel rim (which could be about 3/4 inch to1 inch bigger than the bead seat width). If your (hopefully bolt together) wheels are too wide for the class specs, perhaps you can fix the issue for most reasonable cost by getting new spun inner/outer "halves". Jongbloed Racing Wheels might be a source-- https://www.jongbloedracingwheels.com/

If you're worried about tire dimensions, I am kind of surprised. I don't recall SCCA formula car specs (GCR) that include dimensions of the rubber tire itself (other than as implied by wheel dimension specs). Of course, if there is a class/series that requires a spec tire/manufacturer that would constrain tire dimensions (and much more!).

Lee

[BeerBudgetRacing]

Purchased rains with 9" rears a few years ago. Used one session, and kept in black bags. To my horror, I find out that the rears are now illegal as they are now too wide.

Anybody know why the rules changed to 8" width?

Thanks
Bob

The FC tire in SCCA are now spec. So unless they are the spec rains they won't be legal.

[EYERACE]

Bob,
I too only had the 9s at an SCCA Sebring event about 6 months after the spec tire rule came out. They were about 5 years old and had run once. If I'm remembering things correctly - it rained Saturday night - WIngs & Things was the Sunday 8:00 am grid - I went around and told all other FCs that I was going to 'cheat' and run my 9s. Skip and Herscher and the others (who were likely to beat me anyway) said, "Go ahead." No one marked our tires on grid.

Our last race of the day was at about 11:30. The weather was very cloudy with a temp of about 60 degrees...so it was looking like the track would stay wet. I elected to stay on the rains, others switched to slicks. By the time the green was thrown, the track had pretty much dried.
Oops for me.
If I'm remembering this correctly too, some did not make the grid, some packed up early, one forgot to add gas - so they came in early, one high spotted his car on a berm out of the way and was stuck out on track until the end of the race....and I took first on my 9s in the dry. At impound, no one said anything or objected, even the Marshalls.

Take my advice, run your 9s but tell the other drivers first (emphasizing how old the rains are) and I believe you'll continue to discover that we Southerners are pretty much a 'sporting lot' who care to have this sort of fun and are in favor of getting about as many cars on track as we can. I know I would not object to your 9s.

[Lotus7]

We had a similar issue a couple of years back, turned out we had FE2 tires by mistake, not the spec FC. Happily fixed before it mattered though.

[Steve Demeter]

Kind of silly to implement a spec rain tire when so many folks have several year old rains that would have to be trashed to be legal.

And most of us in that boat would not win with new rains anyhow

But I am happy that your fellow drivers acted reasonably!!!!