dcvee

Ok, coming from the BMW world, we talk about "ride height" to setup a track car. A place to start anyway. Typically measured from center of wheel to lip of fender.

I've seen some posts(and I'm continuing to read)about "1" less than stock". But I've yet to see any hard numbers? I'll continue to look, but it's nice to have a starting point.

Secondly, everyone seems to be running HUGE rear rubber with these cars. I'm used to 235 RA1's! Anyway, I have access to a LOT of 275-35-18's Koni Challenge Hoosiers with 1-2 heat cycles on them. How bad will these be running a square setup on my C5 Z06? I know they take a few laps to heat up but it appears these cars have an oversteer problem on corner exit and folks are using large rubber in the rear to compensate a touch. I'm not looking to plant my foot on the apex...so don't get me wrong!!

And howdy to all.....hopefully, I'll get to meet a few folks as we(myself and some buds)visit some tracks in the NE.

Thanks!
Don

wallyman424

275 is pretty narrow for a rear tire on a vette, but if you can control your right foot why not!

I take it you've done HPDE's before, but this is your first in a vette?

yakisoba

I run 275 hoosiers on my car. It's not bad. Less weight than the 315s too.

Welcome to Corvette! Another thing you can do is toe your rear wheels in a little. 1/8 total is enough. That way, when the rear squats under acceleration, the wheels will be straight and you will get good drive off the corner, rather than oversteer. Not a good alignment for the street because of tire wear, but for track it works. Also depends on your bushings. If they are poly or spherical (metal) you can get away with less camber and toe.

Ride height is generally measured on the Corvette C5 at the jacking points. Likewise rake. The front of the car should be 1/4" lower than the rear to maintain the stock rake. Remember that these cars are bottom breathers, so they have significant upforce on the nose at speed. The rake helps counteract that and allows you reasonable turn in even at 130+.

Good luck and run clean!

AU N EGL

Nope, Ride height is measured to where the A-ram attaches to the frame then to the ground. Fenders are almost never even.

and if you HAVE those 275s use them up.

sounds like you have some seat time already, so thottle modulation out of corners should not be new to you

and WELCOME

davidfarmer

The reason you don't see consistent numbers is that every car is different. You want to leave it a stock ride height, or lower it slightly on the stock adjusters. I usually lower them all the maximum that all of them can turn (ie, if one of them will only turn 1/4 turn, then that's all you should turn any of them). Lowering non-symetrically (without scales) or cutting the adjusters will only cause problems.

I'd forget the ride height, and concentrate on a decent alignment. Also, those tires will be fine. You are going to have sooooo much more oversteer than you are used to (a good thing, once you master it), that no tire will give you the same sensation that your BMW's did. Putting your foot-to-the-floor at apex just doesn't happen in a Vette. Just too much torque......it's not a design flaw, just the physics of having big-bore torque.

Bill Dearborn

Actually we are probably running huge rubber all around compared to what you are used to. A fair number of people are running 315s front and rear.

Bill

63Corvette

Let me be prefectly clear....FREE (or very cheap) tires beat ANY combination of expensive, wide, big name, or high grip tires....period! JMHO

95jersey

The key to being fast in a Corvette is the ability to put down as much power as possible coming out of a turn (hence the need for large rubber).

sperkins

I have just as much fun on free tires as I do on expensive ones.

davidfarmer

tire test after tire test has shown that width alone does not increase contact patch or ultimate grip in many cases.........a good sticky tire, combined with good throttle control, will give great results, fast laps, and a great learning opportunity.

longdaddy

i see no reason why 275 all around would not work. make sure that you set the rake of the car correctly for a different wheel/tire setup than stock

common wisdom for HPDE cars seems to be 3/4 to 1" lower than stock. honestly, I did not notice any difference when I lowered the car.

sperkins

The TTA national champion last year ran on 275 square set up.

Jason

As someone with an E36 DD and Z06 track-car, take it from me:
Prepare for perma-grin.

AU N EGL

shifter77

SAFETY first, helmet to date/restaints/NO red mist. ENJOY.

PA Z06

Don is no rookie to speed, he is coming from a pretty sick turbo m3 so I think he will be fine with throttle control. Congrats on the new car.

ghoffman

Welcome to this side. With a strut car like the BMW, you have different dynamics than a car with uper and lower control arms (LCA) like a Corvette of Ferrari. Over lowering can make it handle worse because the roll centers get messed up. The proper ride height is when the lower control arms are parallel or just slightly angled down. To measure the ride height, I use a simple tool that you slide in between the ground and the frame of the car:

We have a really good selection of other setup tools in the "general" section of our site as well.
http://hardbarusa.com/hardbar/index.php?cPath=25

dcvee

Thanks for all the suggestions/comments guys(and gals if we have any) And thanks for the welcome. I've admired the Vette for a long time now(actually had 2 a LONG time ago)and just decided it's a good time to buy.

So, I'll just leave the ride height alone, do my track alignment and a quick corner balance and we'll go play a tad and see what happens. I'm REALLY excited to pilot this thing around a course somewhere...prolly be Summit main shortly. And yes, I do already have/drive a car that requires throttle control. A 95M3 turbo track car with all the junk, weighs about 2820 and has 460whp. Try that with 235's on the rear...you'll learn throttle control and how to track out right to the curbs!!

Point taken on the wider tire/traction debate. I agree with forward bite but I think the big difference comes via slip angle(cornering). Ok, so my "cheap" 275 hoosiers I'll try first. It's so liberating going to a car that can run big rubber..geez, I actually have CHOICES. In E36M3 land, you either run 235's or you pull fenders and squeeze 255's on. Otherwise you widebody and run 275's!!

Next thing is going to be shocks/springs investigation!! Then I gotta do a bolt-in cage and proper seats.

Thanks for the help and direction!!

Don

dcvee

Nice stuff!!! Over lowering can screw up the roll centers AND induce wicked suspension changes on the BMW as well. In fact, many folks are surprised when they raise their cars back up!!!

Thanks!!

Don

ghoffman

Thanks! BTW, I run 345's in the rear and 295's on the front!