Rake adjustments

[Exhlr8n]

Running the taller Michelin Slicks, Front: 30/65/18 and Rear: 31/71/18

Been playing around with the Rake trying to get the Comp Coupe dialed in a little better.

The "Hoosiers" the VCC Book calls for front height @ 3 3/8" and rear @ 3 7/8", that puts the rake at 1/2"

The Michelin fronts are close to the same height, but the rears are 1"+ taller.

My current set up has been Front @ 3 3/8" to 3 1/2" and Rear @ 4 3/4" to 5 1/4", that puts the rake @ 1" to 1 1/2"

With the Front @ 3 3/8 " there isn't any understeer or fender liner rubbing.

With the rear @ 5 1/4" there isn't much rubbing on the rear liner, but the rear is sensitive to oversteer. Obviously at 4 3/4" there is less oversteer, but a lot more rubbing on liner.

I have a few good sets of Michelin slicks left so I would really like to use them up before switching to the shorter rear Hoosiers.

I know I can raise the Front to reduce the Rake, which should help with the oversteer, but don't want to increase understeer to much.

I believe (would have to check my notebook in trailer) the alignment shims are Front "A" and "B" and Rear "D" and "E"

Anyone else running the taller Michelins and have any set up advice?

Thanks!

Tom

[Desert Venom Racer]

I ran into the same problem using tall Goodyear slicks used by the factory Corvette team. You are correct about the owners manual recommendation of 1/2" rake but that was on the spec Hoosier tire that was designed specifically for the spec BBS wheels that came with the car. My CC suited me best with no more than 3/4" rake so I set the rear ride height as low as possible without rubbing and adjusted the front ride height to 3/4" lower. I think it ended up around 4" front and 4-3/4 rear. Mind you, mine was the earliest version of the CC (Chassis VCC C5). Good luck!

[Exhlr8n]

Wish you guys were closer, I would bring it in.

I'm currently running Michelins

Nitrogen in tires: Cold psi 22-24 Hot 28-32 (depending on outside temps)

Per subesports on Michelins:
Cars using the wider 30/65-18 and 31/71-18 tires (such
as Vipers and Porsche GT1/GT2s)
will perform better with camber settings
closer to -3.0 in the Front and -2.0 in the Rear

Currently do not have suspension settings other than the Rake (not counter balanced, no scales). Looking into getting Balance/Cam/Cas/Toe checked to see where we are at.
Car has the Penske 8765 4 way with duel speed bleeders, do not feel comfortable yet on adjusting them.

It seems to be fairly easy on Tire wear the way it sits.

Do you have any recommendations on where to start with Cam/Cas/Toe once I get the Corner Balance done?

Thanks for any input.

Tom

[RedTanRT/10]

Tom, you should reach out to Ross Murray. He is great on set up and alignment and has a ton of Viper road racing experience

I looked at my specs from him a few weeks ago and noticed he sets things like camber and toe different left to right. All done from lots of experience

[Exhlr8n]

He had set it up before I got it. I just don't know what the settings were then and what they are currently with the Rake changes I've made. The Front and Rear Shims are different as mentioned above. It would be nice to stop by his place on the way out to Inde, if I can coordinate it with him. I'll reach out.

I was hoping to get it done here in town before leaving.

Tire wear is minimal, so I'm guessing its not far off. I'm quit a bit bigger than Kurt, so If anything the counter balancing is probably off a bit.