Greatwhitet/a

iTrader: (1)

Ok fellas,
I have C4 ZR1's 17x11 on the back of my 94 T/A. The other day while diagnosing a vibe and checking for bent wheels I noticed the previous owner placed non "hubcentric" spacers on the car. Thinking this may be a factor in the vibe issue I removed them and put the wheels back on to tell a difference. No difference. I also noted that my wheels are not hub centric either. Also I have noticed that this guy put bumpstop extensions on the car. They do not rub when driving but if the car is in the air they catch the tire (with or without spacer) (spacer is around 1/4")

Here's my issue- 1. Are the spacers neccessary? I have been running without them for a few days, and no issues. I think? If the spacer is necessary, is there a hubcentric option available vs this universal metal frisbee junk?
2. What is the point in the bump stop extension?
3. I cannot fathom why the corvette wheels are not hub centric. Do they need a ring?(where could I find one) I am not sure where the wheels are from, but my guess is they are aftermarket. If anyone has a clue how to tell let me know and I can find out.
4. the wheels have a lot of space in the lug holes(not wallowed out) I have stock nuts on them, but the lugs look aftermarket not sure of brand. Certainly longer than stock. Is the lug nut with its tapered end meeting the wheel supposed to make up all these differences? Is this normal?

I really appreciate the help on here. You guys save me a lot of time and money!!! Plus, you allow me to continue to enjoy this car b/c I am don't go insane trying to iron out these issues. THANKS!!!

firemech21

iTrader: (9)

Im running 17"x11" rear rims on my 99 T/A without any spacer. I have a 335/35zr17 tire mounted on them too. As for the lug nut holes mine are not much bigger than the stud diameter. I could be wrong here, but I believe chevy uses "lug centric" type rims and ford uses hub centric types. Hence the difference in bolt patterns, but if needed you can order hub centric spacers from amazon. I have not had my center caps off with the rims mounted or I could tell you if the rims should slide tightly on the axles.

Greatwhitet/a

iTrader: (1)

I had never heard of Lug Centric wheels, but upon researching what that would indicate. My situation makes much more sense. I really appreciate you mentioning this.

In my research, it was mentioned that a "lug centric" wheel should be balanced while attached to machine thru lugs not hub. I do not know of any shops that do this. Any suggestions?

firemech21

iTrader: (9)

I have run across a few shops that balance tires this way, but I have been a mechanic for 13+ years and could count on 1 hand the amount of shops that I've seen with that equipment. Im going to take my rims off tomorrow and do some more BFHing when I put them on I will snap some pics with the center caps removed for you. Honestly though as long as the rim/tire combo is balanced , the center of the wheel wont change and thats the balancing point. You might want to try some different lug nuts. I am currently using Gorilla lug nuts.

Greatwhitet/a

iTrader: (1)

I thought about lug nuts. I am just not sure what style would be best. What are your gorillas like? Also I am looking at some hub centric rings. they are inexpensive and may help. Do you by chance know what the wheel hub bore is for the zr1 wheel? Won't be able to measure mine til Saturday.

firemech21

iTrader: (9)

Sorry about not getting back to you yesturday my day became hetic, and today I will be at work from 430am until around 730/800pm. So until saturday gets here I wont have time to rip my car apart. I have a chrome set like these.

http://gorilla-auto.com/small.diameter.aluminum.lugs\

standard thread size 12mm x 1.50

leadfoot4

iTrader: (1)

"Lug centric" wheels are simply wheels that aren't hub centric. In other words, the lugs (supposedly) center the wheels, not the hubs. On the LT1 F-bodies, the front and rear had different sized hubs (???), but the wheels had the same diameter centerbore. Therefore, the rear wheels were "hubcentric", while the fronts weren't......or was it the other way around??

firemech21

iTrader: (9)

Alright I took my rims off the car today and did some measuring. The hub portion that slides into the rims measured 2.776" (with some rust). The inner diameter on the rim measured 2.794". I snapped a couple pics. I also noticed on the inner edge of my rims there is a small lip that just slides over the hubs.

firemech21

iTrader: (9)

Here are the pics.