[quick]

Can the stock rear 09 Cayman S wheels be run on both the front and the back of the car without rubbing and without spacers? Does anyone do this? If so, what are your track tire sizes? It seems this would reduce understeer and increase ultimate track grip.

Also, has anyone run the 17 inch stock wheels for track use, and again, has anyone used the wider rear 17 inchers on both front and back axles at the track? I realize the 17 inchers are narrower than the 18s, but using two sets of rear wheels would reduce this to some degree (Take-off 17s seem to be very easy to find).

Thanks.

 

[BillL223]

On my 07, the fronts have 57 mm offset and the rears 43. If you moved the rear to the front, that would mean that you have more clearance inside. Depending on the tire width, you may have to roll the fender to make it work.

 

[alan93rsa]

If you are looking at a 57/43 F/R combo then you would be moving the wheel 14mm to the outside. Add 1/2 the difference in wheel width to that and it should give you a pretty good idea if you have room on the outside. Also check the sidewall width on the tires you want to use.

 

[Jeff G in NE GA]

Member Phat B is running 11.5" wide tires on all four corners of his autocross 986 Boxster. See the end of this thread: http://www.planet-9.com/cayman-boxs...rent-caymans-boxster-competitive-autox-3.html

I've also heard of other Boxster guys racing with rear size wheels/tires on all four corners.

You could search on here, or just swap a rear to front and and find out.

 

[Falcon7]

You are on the right track, You should consider having a set of track wheels made with the correct offsets. That way you could run as an example say 9" front and rear. You would not need spacers or have to roll the front fenders and this would also improve the understeer. If you go with 17 x 9" you also reduce unsprung weight improve acceleration with a smaller diameter wheel and will pay less for the wheels and tires.

 

[Falcon7]

If you decide to go with 17" wheeels check out psvintagewheels.com, they make great custom offset wheels that are priced right. If you are going racing you should also check the rule book.

 

[jmazz]

quick, you are going down the same road as me and I think I have a lot of information you might find useful.

One day just for fun I took my stock rears (18x9 ET43) and put them on the front. They stuck out a lot and the 265 tire was as close as it could get to the spring perch on the inside. Even though they stuck out a lot I jacked up the opposite corner and saw that they would tuck into the fender and not hit on the outside. You could probably run those wheels with skinnier tires to be on the safe side. Some other guys on here have front wheels that stick out about that far. I think the RAC monolites are close. Personally, it was way too far out for me. I took some pictures of it but don't have them here.

For my autocross setup I have decided to go with 17" wheels because Kumho V710s are scarce in 18" sizes. I bought a used pair of old Cup II rims for the rear... 17x9 ET55 with a 15mm spacer. Then for the front I am using a pair of 986 Boxster rear wheels. They are 17x8.5 ET50. They fit the front very nicely. Even though I went with 17's for V710's I ended up getting some Hoosier A6's. 245 front and 275 rear. I may go wider in the front next time but wanted to try this first. Also, I have a 2007 Base Cayman. I am not sure if my front wheels fit over the S brakes. I think they would but haven't checked myself. I bet facelvega knows.

 

[jmazz]

Here are pictures of a stock Cayman S 18x9 ET43 rear wheel on the front of a Cayman. The tire is the stock 265 PS2. The first picture is what it looks like normally. It was just about touching the spring mount on the inside. Of course this is a taller tire than you'd normally run in the front. Bottom line is that I think a 265 tire is too wide for the front and a 9" wheel is probably too wide too. The RAC monolites are 18x9 ET47 so they only sit in 4mm further.
View attachment 12348

For the second picture I jacked up the opposite corner to see if it would hit the fender. It tucks in well so I don't think it would but I still think it was way too wide.
View attachment 12349

 

[diverdog]

It seems this would reduce understeer and increase ultimate track grip.

Thanks.

About the biggest size you can run in front is 255 with out a lot of rubbing. The only advantage to running them all the same is to carry one spare for all and to be able to rotate the tires to any corner.
You will not increase the untimate grip of the car. It will be less than a staggered tire setup. Getting rid of excess understeer is as simple as getting more camber in the front end.

There is a red group driver running 245-18 Hoosiers all around on an 07 CS in NNJR. Not sure what wheels he is using.