shave mounting hub or center of wheel?

**sbird** · 04-18-2007, 12:20 PM

Newbie here....I have a 94 Formula and I am about to buy C5 Z06 rims (argent color and NOT replicas). Fronts are 17x9.5" w/265-17's and the backs are 18x10.5" w/295-35-18's. Before I buy 'em, I tried on one of the front 17's and I had no clearance issues. I then checked the 18" in the rear and I can tell that I will have to cut the edge off the jounce bumper bracket and maybe roll the fender lip. I have no issues with that.....but I could not fit the Z06 rim w/tire over the wheel mounting hub! It seemed like I was off by a damm centimeter when trying to slip the rim center opening over the hub mount, and the tire wasn't hitting anything else within the well to stop the rim from fitting over the hub.

I didn't have enough time to check the other side/rear wheel to see if I would have the same issue, but I heard some guys say that they shaved off just enough of center opening on wheels to widen the hole to fit over hubs. Wouldn't that possibly throw off balance? Afraid of doing that...Should I file the hub a bit?
Anyone ever have this issue with any type of wheel?
Appreciate any feedback, THANKS!

**Eugenio_SS** · 04-18-2007, 01:40 PM

ideally, you'd put a 1/4" spacer in the back... you can always cut the outer half of the bumpstop with no issues.

**mrr23** · 04-18-2007, 05:18 PM

just cut out the center of the wheel. like you said, it's only a slight bit. i use a die grinder and grind it off until it fits. never had a vibration problem.

**sbird** · 04-19-2007, 04:55 AM

Eugenio SS and mrr23, Thanks for your feedback I appreciate it!..I will file open the wheel's center hole and/or spacer.

I also received from a moderator elswhere (injuneer) a detailed reply that I think some of you may find interesting:

"The problem with the rear wheels arises from the fact that the 93 to late 96 F-Bodys have a rear axle hub diameter that is about 0.03" larger than the front hub diameter. The problem was corrected in late 96 model year. The fix is as simple as lightly sanding or grinding the inner diameter of the wheel hub hole until the wheel slips freely over the axle hub. It will not affect wheel balance, and it will not affect wheel centering. The wheels are centered on the axles by the conical lug ("lug-centric").

You could use a spacer. My info, from an old copy of VETTE magazine indicates the OEM Z06 rear 18x10.5 rear wheels have a 58mm offset. That puts the inner edge of the tire against the inner fender liner, and the inner edge of the rim over the jounce bumper bracket. It should not be close enough to the fender lip to require "rolling". A 1/4" spacer would possibly solve the problems on the inside edges, without putting it too close to the fender lip. Close call, and each 4th Gen car seems to be a little different in what will and will not fit. But you would probably need a longer stud. The minimum allowable thread engagement for the lugs on the studs is "one diameter (12mm) of the stud, inside the hex". That means that even if the end of the stud does not protrude through the end of the open lug, as long as there is 12mm if thread engagement inside the hex portion of the lug, you will be OK."

**SexOnWheels** · 04-19-2007, 06:09 AM

Originally Posted by sbird

Eugenio SS and mrr23, Thanks for your feedback I appreciate it!..I will file open the wheel's center hole and/or spacer.

I also received from a moderator elswhere (injuneer) a detailed reply that I think some of you may find interesting:

"The problem with the rear wheels arises from the fact that the 93 to late 96 F-Bodys have a rear axle hub diameter that is about 0.03" larger than the front hub diameter. The problem was corrected in late 96 model year. The fix is as simple as lightly sanding or grinding the inner diameter of the wheel hub hole until the wheel slips freely over the axle hub. It will not affect wheel balance, and it will not affect wheel centering. The wheels are centered on the axles by the conical lug ("lug-centric").

You could use a spacer. My info, from an old copy of VETTE magazine indicates the OEM Z06 rear 18x10.5 rear wheels have a 58mm offset. That puts the inner edge of the tire against the inner fender liner, and the inner edge of the rim over the jounce bumper bracket. It should not be close enough to the fender lip to require "rolling". A 1/4" spacer would possibly solve the problems on the inside edges, without putting it too close to the fender lip. Close call, and each 4th Gen car seems to be a little different in what will and will not fit. But you would probably need a longer stud. The minimum allowable thread engagement for the lugs on the studs is "one diameter (12mm) of the stud, inside the hex". That means that even if the end of the stud does not protrude through the end of the open lug, as long as there is 12mm if thread engagement inside the hex portion of the lug, you will be OK."

injuneer is exactly right, and as said it is an easy fix.

**Eugenio_SS** · 04-19-2007, 11:09 AM

i would not sand, grind either the wheel or the hub... if anything, just buy 2 hubs or 96+ years. last thing you want is unwanted vibration due to non proper centering.

**SexOnWheels** · 04-19-2007, 01:41 PM

Won't the studs keep the wheel centered?

Also it is the wheels that need light grinding not the hubs?

**2MuchFun** · 04-19-2007, 03:23 PM

so to add a spacer you have to put all new longer studs in.......that sux, i had to replace 2 studs on the front, some dbag stripped the threads before i had the car!!

**SexOnWheels** · 04-20-2007, 06:28 AM

I just replaced mine with ARP studs. The first hub I removed to change the studs. They came out so easily that I just tapped them with a hammer on the next wheel with out removing anything but the rim/wheel.

It is a real easy job and the ARP studs are far superior!

**sbird** · 04-20-2007, 07:32 AM

Alright Guys, just put the rims on yesterday, here's what I did for the rear:

-Threw on 7/32" spacers (just a hair smaller than 1/4" spacers).
-Trimmed off some of the jounce bumper bracket to avoid inner wheel rub.
-Took a Dremmel and opened up the rim center opening just another 2mm.
-Threw the wheels on and had no issue getting the lugs to tighten on at least 3/4 of the studs(I was more happy about that than anything else 'cus I didn't want to have to put longer studs if I didn't have to. If i couldn't get the lugs on that far, then I would be putting on longer studs).
-Didn't have to use a mallet for anything
-No tire rubbing on the lip (and it's lowered w/eibach prokits), but I will be rolling the lips regardless for piece of mind.

I ran the car up to 70mph yesterday (couldn't go any faster yet 'cus of traffic) and no vibrations....Very happy with the new setup.

Hope this helps, but you guys know that all F-body's are not the same, so what worked for me may or may not work for you.....and thanks again for the tips and advice.

**Eugenio_SS** · 04-20-2007, 07:48 AM

Originally Posted by SexOnWheels

Won't the studs keep the wheel centered?

Also it is the wheels that need light grinding not the hubs?

not necessarily... the wheels are not lugcentric... they are hubcentric, using the lugs simply for tightening, not to make sure it's centered.
actually the only way to have that is to make sure that your lugnuts are tappered in the end... and then you do have it.

**mrr23** · 04-20-2007, 07:17 PM

Originally Posted by Eugenio_SS

i would not sand, grind either the wheel or the hub... if anything, just buy 2 hubs or 96+ years. last thing you want is unwanted vibration due to non proper centering.

it's the rear. he'd have to buy axles to do it your way. you could say it's both lug and hub centric as it does fit snug on the hub and use conical lugnuts. whatever little but he will grind off, will be made up by the lugnuts.

**mrr23** · 04-20-2007, 07:20 PM

Originally Posted by 2MuchFun

so to add a spacer you have to put all new longer studs in.......that sux, i had to replace 2 studs on the front, some dbag stripped the threads before i had the car!!

you can use a 7/32 spacer and still be fine with stock wheel stud length. personally, i would rather grind out the center of wheel versus using spacers. if a spacer ever cranked and fell out from inbetween the wheel and hub, you suddenly have a loose wheel.

i do use a 7/32 spacer on the front when i use my drag wheels. but, i'm not always on those wheels and can look at the spacer everytime i swap around to go to the track.

**sbird** · 04-23-2007, 04:20 AM

Eventhough I used the 7/32 spacers, and after I grinded open the rim center opening just a bit, I was actually able to still fit the entire rim onto the wheel hub....so the rim face and hub face where flush, no rim sticking out past the hub (if I put a 1/4 spacer, the rim would not have been flush with my hubs).

I also did use tapered lug nuts, so I feel comfortable enough knowing I have a secure set up.

Thanks Guys.