Canam

Thought I'd throw this up for those who already know.

I have purchased my fourth Vette, an 85 C4 full on race car. It runs the stock 16 inch Z51 wheels which are 9.5 inches and that's fine.
I eventually will want a bigger contact patch. ZR1 stock 11 inch rear wheels will fit with no spacers as they are 38mm offset.
Is there a front aftermarket wheel 9.5 inches that at least looks like a ZR1 wheel ? See where I'm going here? I don't want to put the 11 inch ZR1 wheels on the front also.

Or are there decent aftermarket wheels that I can get in 11s for the rear and 9's for the front?

thanks for any help.

Pat.

RacePro Engineering

Hi Pat,

A lot depends upon what brakes this new "full on race car" has, but my initial thought is this, "Why wouldn't you want 11" wide wheels on all four corners?"

Unless absolutely EVERYTHING has been moved from the front of the car to the rear, the normal characteristics of the chassis will be to understeer. Having larger contact patches at the front will help balance this tendancy.

Simply answering your question, you can certainly find sets of 9½" x 16" fronts with 11" x 16" rears that will fit over the stock calipers and rotors. They are readily available. Maybe with a little more information from you, we can help you zero-in on what will be a better solution.

Ed LoPresti

[After-thought] There are a bunch of reasons why a "square" wheel setup can be preferred on a Corvette - performance, economic, and practical.

eogel

How about posting some pictures and tell us about the car. The few of us who race C4's like to know about others.

Thanks,
Ed

Canam

Sorry no pics yet, its on a trailer on its way from Atascadera CA. It is an 85 C4 built by a Texas guy that ran in the southwest division and is NASA ST2 and SCCA GT1. Its a home grown Texas car built to race on 06.
Brakes are stock with lines and pads. I'm leaving them stock for now until I sort the car out to my liking but its already very well built and very reliable with a well built 355CID motor, no ecu, carb T10, etc.

I'm not sure the front hubs, geometry, and clearance would work. I do still have the power steering. If guys run the larger wheels on the front with no issues thats good for me. I don't like to run different wheels for rotation reasons like everyone but I will if I can. Actually, the cars works very well with the 16's and of course tires are cheaper.

vettehardt

A lot of people run 17X11 on all four corners. You can get aftermarket ZR-1 wheels in a 17X9.5 or 17X11 in offsets to work on your car. Look on Ebay, there are a ton of them on there. Look at the forum sponsors also. Some race wheel manufacturers (like BBS) will make wheels to any specs you want.

Crepitus

What I have learned so far...The aftermarket stuff can be very heavy. If you can afford 3000$ a set CCW or Kodiacs. LG sells C6 fronts that are about 21 lbs 18x10.5 38mm offset, for under 2000$ a set iirc. I went with the budget option, C5 Z06 17x9.5 with 1" adapters. Z 18x10.5s are also out there but more $$. The 17x9.5s are hand me downs from T1 guys that run the 10.5s on all 4.
Big slicks can be really hard on wheel bearings.

Lets hear more about your new race car!

Canam

Well, if lots of guys run the 11's up front maybe that will be a plan. Very true about upgrading to larger wheels and trading unsprung weight for contact patch. Thats why I'll be doing extensive testing beforehand on the 16 inch wheels. If I decide to go to 17's I'll use the 16's for rain tires.
ZR1 wheels are 38mm and are the only stock (factory) larger wheels that fit with no spacers which I prefer in a race car, think everyone does. Guess because its an 84-87 model there's not a lot of aftermarket support. I'll also do a search to see what other cars use 17 inch wheels with the 38mm offset. Its not a big deal really right away, the car is tuned to run what it has and runs pretty quick. We'll see.
When it comes in next week I'll scrutinize everything and then its off to here http://www.calabogiemotorsports.com/ to test on the 15th. Getting cold up here and most tracks getting ready to shut down for the season.

Cars ST2 spec right now. I'm unlimited up here in what I can do to the car for the class I run in. Right now its dynoed at 335/375 to the wheels. After testing I'll make the "next year" plan which of course always involves budgeting. My last racecar cost me a lot of money that I'm still recuperating from.

RacePro Engineering

Now, Pat,

You don't really think that is going to change, do you? It's just that the recuperation process becomes more common as the recuperation time grows longer

Ed

Canam

So true but there's spending money and there's spending money needlessly, like when you melt a piston because the engine builder puts the scraper rings in upside down, oil blowby causes too much heat in the top end and combustion chamber, and it costs you 10 grand plus for the rebuild. Thats why I've gone back to a vette.
Blow a motor, order a 383 stroker for less than 5 grand and bolt it in.

It was one of them there furren cars. We run enduros and it was always very fast....right up until it would break

ScaryFast

Personally I like a square 275 setup on a C4, especially if you can get the car under 3000 lbs. Corvette guys love to over-tire their cars and it's often a waste.

I've had better results with 275 square than with 275/315. I've run a little quicker on 315 square, but for ST2 that means adding weight. So I don't like it.

Canam

That can certainly happen. Apprently mine does well on the square 16's.
They're Z51 wheels so they're 9.5 inches. Might be good enough.
My car weighs 2700 lbs.

BrianCunningham

CCW can set you up with whatever size and offset you want.

But why on 9in in the front?

jaa1992

I'm with Scary a square 275 setup works well on the C4.
WIth the 16" I'd check Hoosier's site and see what sizes they have.
You are considerably lighter and might be able to get away with a 255 or 265.
I know if I could stand a real short sidewall I can get 255x35/18 that have the same treadwidth as the 275 I have on there now.

I've run 315 on 17x11" wheels square and there is not much difference in handling. When I ran 275 front and 315 rear street tires it had a tendancy to understeer badly. Now I have a 92 so I can run the Z06 or C5 rears on all 4 corners without spacers.

Canam

Sounds like a square setup it will be. 275's are a lot cheaper than 315's also but I might try the ZR1 wheels. I'll know more after testing next week. Part of this I'm kinda sorry to say is those pie plate wheels sure are butt ugly. Never liked them. They look like something that should be running Bonneville. I really like Kosei K1 wheels. Tough and very lightweight.

BTW whats CCW?

ScaryFast

My suggestion is to browse the C5 and C6 4sale sections and buy their knock off 18's. There are a plethora of 18x9.5 wheels for $100 each, factory corvette stuff that is light and sturdy.

18's are easy to get in Corvette widths, smaller diameters...not so much.

18" scrubs can be found all day long, although usually in the 315 size, but 275's can be found.

Canam

Wheels won't fit. This is an 85. Even the 88 to 96 wheels won't. I'd rather not use spacers.

jaa1992

And therin lies your problem. You'll have to live with what you have or go aftermarket. Which is why CCW was suggested, they make a light wheel in pretty much any offset, size, width you could wish for

Canam

just found that. Very nice, the black ones. Thanks everyone for your help.

Re connecting with the corvette population is exciting for me. Its where I belong. Been racing for 20 years and I am very happy to be in one once again

Crepitus

http://www.ccwheel.com/ these guys speak fluent Vette and Porsche

Kubs

I have 4 OEM C6 Z06 FRONT wheels which are 18x9.5 with a 40mm offset and 275/35/18 A6s. They dont stick out of the stock fenders on my '90 and will also fit well with the early C4 and no spacers. The hard part is trying to find people willing to sell only fronts. They are light and I was able to find 4 wheels for less than $500.