Did my First autocross event today...

[frank s]

285s are stock on the 07-09 GT500 18x9.5 wheels. Of course the Goodyear F1 tires and the wheels are very substantial (heavy); I'd have to guess they'll behave differently from lighter, stickier combinations of the same sizes. I ran the 9.5/285 GT500 combo for many laps on track, and they worked OK on a 2009 GT, P springs, Koni Yellows, thick sways.

The local F Stock autocross "standard" for 19-inch Mustangs is the 295 Hoosiers on 9-inch rima.

 

[Jucostud]

video moostang09 shot of me this weekend . Nice donut shot

 

[D98GT]

Awesome video

 

[Vorshlag-Fair]

295s on 9.5's aren't terrible. They work, but you will be lacking a lot of feel. Here is a picture of my car with 295/40s on a 9.5. They're a little bulged on there so it's definitely not ideal

Gah! A little bulged?! (faints) hehehehe.... but I do agree, while it will work on a 9.5" wheel it loses a lot of transitional responsiveness and "feel" relative to the same tire mounted on a 10-11" wide wheel. I tried the same 295/40/18 Hoosier tires on an 18x10" wheel (below) and I felt it was a bit squeezed on that.

Ideally for this Hoosier 295/40 I would go with a 10.5" or 11" wide wheel, but those sized wheels don't grow on trees so... I get it.