pmillerny

Hey folks,

I just bought an '07 Cayman S all set up for track duty. I'm looking into an extra set of wheels & tires and came across a set of wheels of a narrow body 996 that looks to be a good deal. The widths are 1/2 inch wider in front and 1 inch wider in the rear (plus the offsets are different which I hope to address with spacers) and I presume there are limits to how narrow a tire I can run on the wider width at the rear. My question is - How will the wider tires impact the chassis dynamics?

My gut tells me that it will increase understeer but I was wondering if anybody was using similar set up and what they thought of it. All informed thoughts and experiences are appreciated.

Pete

fhp911

Why does your gut tell you that? What would the tire sizes of the fronts and rears be?

Fly911

The 996 wheels are typically 8"x18"ET50 and 10"x18"ET65. You will need 25mm spacers in the back to get to the correct offset for the Cayman (from ET65 to ET40). Tire size should be 234/40-18 and 285/35-18 or 295/30-18. I have run both rear sizes on my Boxsters, if you choose Toyo R-888, the 295's are actually $100 less per tire than the 285's! You should have around -3 degrees camber on all 4 wheels.

pmillerny

Thanks guys. I assumed that wider wheels would require wider tires. Half inch wider I the front and a full inch at the rear would give me twice as much incremental grip in the rear. By now it should be obvious that I'm no chassis engineer!

Fly911 - Thanks for the info! Always great to hear from somebody that's "been there, done that." Any downside to running 25mm spacers?

pmillerny

Thanks guys. I assumed that wider wheels would require wider tires. Half inch wider I the front and a full inch at the rear would give me twice as much incremental grip in the rear. By now it should be obvious that I'm no chassis engineer!

Fly911 - Thanks for the info! Always great to hear from somebody that's "been there, done that." Any downside to running 25mm spacers?

Fly911

For the track, you have to use spacers that come with longer bolts.

For 25mm spacers you can get a type where you bolt the spacer on using the original wheel bolts, and then there are 5 studs in the spacer with nuts for the wheel. This type can not be used on the track, because you have no access to torque the inner bolts.

You have to use the type with longer through bolts, from FVD, H&R or a similar recognised manufacturer. Don't use cheap "made in China" spacers.