What Wheels/Tire set up on your GT body race car? Options

[jmz]

What's everyone running for wheels and tire size on their race cars?

Do you go with a staggered setup or square?

What size wheel?

What size tire?

What do you run for rains?

So far I've tried

15x8&9 with 245x40x15 DOT comp tires on all four corners Maxxis Victra RC-1

16x10 with slicks on all four corners. Dunlop 265x60x16 slicks


I'm most likely going to run 16x8&9 next weekend with 245x45x16 on all four corners with RA-1s.

I've got some 15x9&11 that I may try down the road with my local club

and when I run COTA with SVRA later this year I'll have to go to 15x8 on all 4.

I'm new to this car and am still learning it and learning to race.

[Cracker]

Regarding the spoilers, splitters, spoiler and wings....

My on-track experience leads me to believe:
1) The duckbill spoiler is of no tangible performance value but it does greatly help the aesthetics of the rear on a 914. That air is dead as dead as can be...
2) The spoiler is a decent place to mount brake cooling ducts but not much else..it increases drag vs a stock valance. The increased stability is probably a function of the car being slowed down due to the increased vertical surface area. I run this air-dam too...
3) A wing needs to be way the hell up there to grab clean air - the bottom of my wing is 1" (and should be higher) above the highest point of the roof line.
4) An actual splitter must be able to support at least 250 pounds of direct vertical force to remain stable at speed. My first effort fractured at 160 mph (mid-corner T9 RA) and I thought I had lost a wheel!!! IF you install one - bring it back all the way to the front suspension cross-member - there is more to aero than just the leading edge reveal.

Not meant to offend and step on toes - just sharing what I have learned...

T

[tjtryon]

I am replying to this 5 year old post, as I think it may still do others some good with their aero. Aside from access to a wind tunnel, this is by far the best way to find out where to tune your aero goodies.

Get some of your wife's favorite yarn and cut it into 3" pieces. Use scotch tape to tape a hundred or so all over your car. Set up as many GoPro cameras as possible. Use your GoPros, use your buddies, bug your third cousin, just get several of them. Attach to outside car, pointing to the main areas you have taped the yarn (you can always repeat this with the camera looking at other areas), to find out what the air at body panels is doing, and use that info to tune your aero goodies.

Check this video: Video of Aero with yarn

Regarding the spoilers, splitters, spoiler and wings....

My on-track experience leads me to believe:
1) The duckbill spoiler is of no tangible performance value but it does greatly help the aesthetics of the rear on a 914. That air is dead as dead as can be...
2) The spoiler is a decent place to mount brake cooling ducts but not much else..it increases drag vs a stock valance. The increased stability is probably a function of the car being slowed down due to the increased vertical surface area. I run this air-dam too...
3) A wing needs to be way the hell up there to grab clean air - the bottom of my wing is 1" (and should be higher) above the highest point of the roof line.
4) An actual splitter must be able to support at least 250 pounds of direct vertical force to remain stable at speed. My first effort fractured at 160 mph (mid-corner T9 RA) and I thought I had lost a wheel!!! IF you install one - bring it back all the way to the front suspension cross-member - there is more to aero than just the leading edge reveal.

Not meant to offend and step on toes - just sharing what I have learned...

T