I've noticed that A LOT of vendors will have bolt patterns not suited for the corvette's.

5x120.65 (stock)

popular bolt pattern 5x114.3

anyone running adaptor converters? Advice, experience, etc? thanks!

 

If you run an adapter, you are going to have to get a wheel with a different offset in order to compensate for the thickness of the adapter which may limit your choice of wheel further.

 

I already took that into consideration.

really, the "only" cost effective wheels that measure 10"+ are the ZR1's, c5z06's, and the new c6z06 offering with the 10.5" wide rears. these wheels also tend to be relatively heavy. It's one of the reasons why aftermarket wheels from "other" vendors start to look more appealing.

CCW's
fikse
forgeline
HRE

etc. the problem is that the above wheels are also VERY expensive. With the CCW's being the "bargain" price.

Companies like

Volk
rays
SSR
Konig
Enkei
kosei
bbs

etc. seem to offer an excellent range of wheels (usually between 7.5"-10.5" wide) that are relatively affordable, and super light weight.

I know the autocrossers here would be more inclined to pursue a light weight set of wheels, since upsprung weight makes a HUGE difference (at least on lighter, smaller cars).

there are literally 3 style of wheels that I would "love" to run just from Enkei. Only the RP-F1 comes in a 5x120 bolt pattern (yes this BMW bolt pattern WILL fit a corvette). But the Problem is that the RP-F1's in this bolt pattern are 19" in diameter (too large for my taste, would prefer 17"s, but will go 18"s since they are now more popular).

The offsets are much less than what we're accustom to seeing for vette's (typical 17x11 ZR1 for a base vette' is at 50mm). the 5x114.3 bolt pattern 17x10" RP-F1's are like 30-38mm offset (I'll have to check the website to double check).

Of course, I'd have to purchase a set (or at least convince the local discount tire to order a set) to get them on the vette' to see exactly how much of an adaptor we would need to run these.

the other "appealing" set of massive wheels would be the ones currently offered by corvette-wheels.com 18x12 c6z06 wheels style. Of course, they don't have an offset available specifically for the c4... but i think the ones intended for the c5 with spacer/adaptor will work. I haven't heard back from them to confirm that they will fit a c4 without spacers.

just as an example Enkei's 17x10" wheel is something like 17lbs! the 17x11 ZR1 wheel is probably around 25-30lbs depending on the aftermarket vendor and their casting facility.

 

some quick calculations:

17x11" 50mm offset = 7.468 back space (3.53 front space- from mounting point to front lip)
17x11" 36mm offset(ZR1) = 6.917 back space (4.08 front space- thus the reason why the ZR1 offset places these wheels outside the base c4 body line)

17x10" RP-F1 38mm offset = 6.49 backspace (3.51 front space)
17x10" RP-F1 38mm offset with 1" 5x4.75 to 5x4.50 adaptor = 5.49 backspace (4.51 front space- nearly 1/2" FURTHER out from the stock ZR1 [36mm] wheel).

 

c6z06 wheels

18x10.5" w/58mm offset = 7.533 backspace (2.967" front space) this would be "nearly" perfect for the c4.

18x12" w/59mm offset = 8.322 backspace (3.678 front space)

comparison to 17x11" ZR1 w/50mm offset = 7.468 backspace (3.532 frontspace)

the c6z06 12" wheel should sit "just" about .14 inch further outward that the traditional 17x11 50mm ZR1 replica wheels. and the backspace would essentially be "almost" one inch inboard....

I don't know if we (c4 owners) have the additional room inboard to clear the bigger 18x12" c6z06 wheels


however, I have seen guys widen the 17x11 Zr1 wheels by about an inch to run wider tires... i don't know if these guys ended up running spacers?

 

Your calculations are in "error"! I don't know but suspect their origin but here is a "quick fact" -- total wheel width of a 17 X 11 wheel is a number closer to 12". This can vary +/- 1/8" or so but seldom more.

Back spacing on a 50mm 11" wheel is nearly 7 15/16" +/-

Back spacing on a 36mm 11" wheel is nearly 7 7/16" +/-

 

These are in "error" also!

I'd suggest you do some serious research before attempting a wheel purchase or comparison. I'm on the way "out the door" for work or I might do a couple more comparisons for you but I believe you'll enjoy the research!

 

Well, the calculations were based on a "true" 11" wheel... I was trying to see some comparisons in relation to widths currently available.

I would appreciate your educated advice, as the "only" way i can think of actually getting any accurate measures would be to get a hold of a set of each and actually measure them (unlikely).

I was hoping someone has some hands on experience with these bolt pattern conversion adaptors.

 

The realistic solution and actual best advice would be to buy "direct fit" wheels, an adapter to "down size" the bolt circle would be a poor choice.The additional expense if there is any would pay dramatic benefits down the road. It appears your car is maybe a '93 and I'd guess quality wheel choices should be readily available.

You need to lose all the thoughts that you've got regardinng wheel dimensions and for sure the "front spacing"! When you deal with what you want to call "front spacing" you need to deal with the tire/wheel combination as a package. It's also wise to use the tire/wheel package to deal with the inner clearance or backspacing of the tire/wheel package.

Here's a link to a quality wheel tire comaprator, you can do "side by side" comparisons. It's not a substitute for undersatanding but it will get you some required information/knowledge:

http://www.bigcustomwheels.com/rt_specs.jsp

Remember the actual width of a wheel is approximately 1" greater than it's advertised width! Take a tape measure and go to a wheel reseller and check for yourself! All/most wheel comparators use advertised width "inside flange to inside flange" that the tire mounts to.

A good strart with this link would be a 31535R17 on a 17 X 11 36mm (left) and the same on the right but a 50mm offset. You'll learn a good bit from just that comparison I believe!

 

WVZR-1,

I totally agree with you. I don't want to go with an adaptor combo, but as previously mentioned, the weight of the current offerings is an issue (when also taking cost into consideration).

I might end up (more than likely) going with the ZR1's or the c6z06 17/18 combo for now, and eventually getting a serious set of wheels later (i.e. ccw/fikse/forgeline/work/etc).

 

As we spoke before, I have an 18x11 with a +59 offset. On my car, another 1/2 inch inward with the z06 wheel and I will hit the sway bar, especially under side loading. Just a thought.

 

bam92- i do recall the conversation. With this thread, I was actually looking to get more information on adaptors (to run different bolt pattern wheels).

the c6z06 just seem to keep coming up as an appealing alternative.

you think the 18x12's with the 59mm offset would work with grand sport flares and a spacer to push it outward enough to clear the sway bar?

 

I am going through this on a C5.

Ebay has plenty of adapters for sale.

Adapters with wide wheels on a Corvette = Nightmare.

I have tried so many different setups, but the massive back spacing screws up everything unless you want to go with a narrower wheel and tire and then the car won't look right.

The painted 17x11 ZR1 with 50mm offset at $125. (tires.com) is as good a setup, fit and price as just about anything else. There are probably venders on here selling that same wheel.

I am going for a drag setup and want the most sidewall, so I want to make do with a 16". I will be going with GTO spares, M&H front tires, 16" Z28 wheels on rear with M&H 305-50-16 DOT's.

 

Yes. Why not just get the factory 19x12's? I have thought of this but I would then want 19x10's on the front. Wheels are relatively cheap but the tires, if not used, get expensive. I like the new spider wheels off the z in black powdercoat.