RacePro Engineering

Gentlemen,

We are looking for guidance in finding 11" x 16" wheels that will fit our 1995 C4, with the J55 calipers/rotors installed on the front, regular C4 brakes on the rear.

Any assistance will be greatly appreciated.

Thanks,
Ed LoPresti

69autoXr

Real Racing Wheels

https://www.rsracing.com/rscatalog/a...rrw-pro616.asp

Not sure about 16's with the J55's though.

Be aware that Real doesn't measure their backspace from the outermost flange, the measure just inside the inner lip, so add 1/4" to whatever backspace they advertise.

RacePro Engineering

Thanks for the suggestion. However, the link does not seem to be working - at least on my PC. Any chance they moved to a different address?

Ed

Git Er Dun

I tried the link and it is working for me at least. Maybe try it again?

Sidney004

Ed:
What is the reason behind the 16" wheels, low rotational mass? Is there good tire availability with 16's?

RacePro Engineering

Sidney,

There are a number of reasons, and lower rotational mass is certainly one of them. Cost is another big one.

We are going to run slicks, so other factors make the 16" diameter more favorable:
[1] Lower unsprung weight.
[2] Better torque.
[3] Lower ride height without modifying suspension geometry.
[4] Better aero effects.
[5] Lower center of gravity.
[6] Stiffer sidewalls.
There are probably other small benefits that I am too lazy to recite right now.

You do raise a good point about availability. With the current craze for always and ever larger diameter wheels, most tire manufacturers have their sights set on the 18" and 19" ($$$$$) markets. Fortunately, Goodyear and Hoosier are still producing a variety of wide slicks in 15" and 16" diameters, and various compounds.

Now, where can we get these wheels?
Ed

littlesk8cracker

the generic 5-spokes (zr1 style, a-molds) that are found on alot of c4's can be bought in 17x11. i know you said 16, but 17 isnt too much different. plus the backspacing is already set up for late model c4's so you wouldnt have to worry about that. plus theyre pretty cheap

69autoXr

25x12-16 Hoosier slicks are popular with the CP crowd (Mustangs and Camaros), I don't see them going away anytime soon. They can be squeezed onto 11's; they're spec'd for 10-12" wheels. 11 is a bit of a squeeze (I can't imagine putting them on 10's), but the tire looks good once it's on. 12" is more ideal, and is what I would get if I were buying new, particularly for a C4.

The link works for me as well. If not for you still, google "rs racing" and Real Wheels can be purchased from them.

vettehardt

When you click on the link does it do anything? Does it open anotehr window? I have been having a problem with my desktop computer at home not wanting to open links like that. I think it has to do with a recent update for IE 8 and java scripts. What I do is right click on the link and select "coppy shortcut." Then you can past that into your address bar and hit enter to take you to the website.

On the computer here at work, the link works correctly. Of course this computer is still running Windows XP and IE 6.

Sidney004

The link works for me too, here is their email address:
sales@rsracing.com

Order/Tech Line (515)462-3432 US

RacePro Engineering

littleskate,

Those are all good points, EXCEPT that both Goodyear and Hoosier sort of "skip over" the 17" diameter in 10", 11", and 12" slicks. Hoosier does make a little narrower one that would kind of work, but only available in a harder compound.
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69autoXr,

Now I am curious if you have actually gotten race wheels from Real Racing Wheels; and if so, do you use them on road courses?

Through Google, I was able to get contact info, and phoned them. If I were speaking with BBS or Fikse, I would ask for their Corvette expert on fitment, and I tried that with Real Racing. I somehow ended up with the "expert Steve", who had no knowledge whatsoever of a C4's suspension geometry, or brake specifications. Indeed, he was shocked to think that someone might try using one of their three-piece wheels for speeds approaching 160 MPH! He knew that the centers were aluminum, but could not tell me if they were forged or cast. I quickly lost interest.
--------

vettehardt and Sidney,

I do appreciate your suggestions on getting 69autoXr's link to work, and on contacting Real Racing. I think what is really needed here is insight from someone who is currently using 11" x 16" wheels with the larger brakes, and get exact wheel measurements from that person.

Ed

69autoXr

Yes and yes to your questions, I have two sets (they were on the car when my avatar picture was taken) and have ran them on road courses but never anywhere close to 160.

The link I provided was for a distributor. If you talked to them then perhaps they can't give you much information, try talking to Real directly. http://www.realwheel.net/ Their site has an FAQ that lists maximum brake diameter for 16" wheels as 15-5/32".

0Fikse Wheels

Fikse Corvette Expert right here - danny@fikse.com or (425)572-0427

RacePro Engineering

69autoXr,

I am reassured to hear that you have had good luck with these Real Racing wheels. And yes, I did phone the company directly, just as I would with any part manufacturer. Apparently I am talking to the wrong people there, but Steve was given to me as the "Corvette expert". That maximum brake "diameter" you found must also include the an allowance for the caliper. ? .

-------------

Danny,

I shall be very interested in getting your "take" on all this, and will be pleased to telephone you on Monday. I'll have to check my notes, but if memory serves me corretly, I worked some time ago with a gentlemen at Fikse named Dan, for fitment of one of our 911 wheels.

--------------

Assembling the various bits and pieces of information I have collected so far, it appears that Enkei produced a special 16" wheel for the C4 that did (does) clear the J55 brake rotors and calipers. It apparently had a backspace of 36-38mm. It was produced in 8½" and/or 9½" widths. I have not yet been able to learn this wheel's inside diameter, or whether or not they produced these in wider (like 11") widths.

Ed

STEVEN13

Hi Ed,

It's Steve from Long Island-we spoke last month.

Good luck with the '95!! I think you will be happy with the LT1. When you get it together-post some photos.

Steve

RacePro Engineering

Hello again, Steve,

Thank you for the well-wishes. I truly enjoyed speaking with you about your 1992. Have you decided to put it on the For Sale forum yet? When, and if, you do, someone is going to get themselves a very nice machine! And, maybe you will be back at the drag strip soon again thereafter!?!

Best,
Ed

0Fikse Wheels

Hi Ed,

If you worked with someone named Dan, it was most likey me as I'm the only Daniel/Danny/Dan that has ever worked for this company and I was with the old Fikse back in 2007-2008. In any case, if I can be of any assistance to you, please don't hesitate to give me a shout!

Respectfully,

Danny G.

Bill Dearborn

Ed, do you remember my white 86? I had a set of the Enkei wheels which were introduced on the Z51 cars in 86. Those wheels were 16x9.5 and would definitely fit over the J55 brakes I installed on the car. The original 16x8.5 wheels would fit over them as well. When playing around with 16 inch C4 OEM wheels I found out quite a bit about what fits and doesn't fit the J55 brakes. The Enkei's definitely will fit over them. You can tell the Enkei's by looking on the backside of the spokes. They will have the name cast into the spoke. Some of the other OEM wheels fit as well. I had a set of 5 1984 16x9.5 wheels and found that 4 of them would fit. The big difference between them and the Enkei's was the amount of casting flash on the back side of the spoke where it joins the barrel. The Enkei's were much smoother and cleared the calipers. One of the 84 wheels fit after I used a file on the outside corner of the caliper to grind down the corners of the fins by an 1/8 inch or so. There isn't much room between the caliper and the barrel so small stones picked up by sticky tires rub between them as the wheel turns.

Enkei never made a C4 wheel wider than 9.5 inches.

Using the 16s on a 95 might cause other issues due to different offsets between the early and late C4s. The 16s might not have enough offset. For instance a C4 ZR1 17x11 wheel will fit quite well on an early C4 but will stick out to far on a non-ZR1 late C4. The non ZR1 cars had to use the Grand Sport Offset 17x11 wheel so they would tuck under the fender better.

I would suggest you look at 17 inch wheels. I have seen a number of C4s that were using 17x11s at all 4 corners.

Give me a call and we can talk. I will be in your neighborhood this weekend as I will be instructing for NASA/PDA at Watkins Glen.

Bill

RacePro Engineering

Hi Bill,

So sorry my promised call to you never got made! Dante and I were camped-out under the Cobra, getting it ready for last weekend's Fun One. After the races, the fatigue must have lodged in my memory center . . . . .

I should have realized you know all about this stuff from a first-hand perspective. I'll telephone you in a couple of minutes.
Ed