a few questions about wheels and springs...

[pig_iron]

Howdy ZR1 enthusiasts. I have a few questions about the car that I can't seem to get answered anywhere else. Firstly, I have a 91 Z and I want to upgrade to 18 or possibly 20 inch wheels. What would be proper backspacing in the rear to enlarge to 12 inches wide? I want a good look that fills out the fenders but doesn't exceed them or cause rubbing. Also, with the addition of a larger wheel, it may cause an unsightly change in ride height. Is it possible to lower the car TASTEFULLY (1-1.5 inches) to compliment the larger wheels? I have looked for an aftermarket lowering spring for the ZR1 or even just the C4 and I cannot find a manufacturer anywhere.
Thanks for any info.

[Z Factor]

Hello, and welcome to the forum.

I'm not a "wheel person", but someone will be along to help you out.

The ZR-1 along with other C-4's can be "TASTEFULLY" lowered.

[rkreigh]

Howdy ZR1 enthusiasts. I have a few questions about the car that I can't seem to get answered anywhere else. Firstly, I have a 91 Z and I want to upgrade to 18 or possibly 20 inch wheels. What would be proper backspacing in the rear to enlarge to 12 inches wide? I want a good look that fills out the fenders but doesn't exceed them or cause rubbing. Also, with the addition of a larger wheel, it may cause an unsightly change in ride height. Is it possible to lower the car TASTEFULLY (1-1.5 inches) to compliment the larger wheels? I have looked for an aftermarket lowering spring for the ZR1 or even just the C4 and I cannot find a manufacturer anywhere.
Thanks for any info.

contact John @ CCW. www.ccwheel.com he has some really nice billet wheels in 18" or 19" stay away from 20s. you don't need new springs to lower the car. you get longer bolts for the back, in the front you remove the "shims" which is much more involved as you need to pull the spring to get at them. If you are going that far I would definitely consider coil overs as you can then tailor the spring rates and they minimize the "cross talk" that cause the rear end to get a little twitchy around bumpy corners.

good luck!!!

[Mikez40]

I would stick with 18", I think 19 and 20 look funny...I have 18x10 in the front and 18x11.5 in the back with 275/35/18 front tires and 335/30/18 rear...I think the 18x10 in the front are a great choice. but I would of liked to put 18x13 in the back with 345/30/18 tires.. that is about as wide as you can go... The tire hight is just slightly higher than the stock tires, so it still looks good....

I have not lowered mine, but would like to one day...That will fill in the wheel wells....You just need longer bolts in the rear to lower the back, but the front is a little more complicated. You will need to remove the spring and and replace the wedges that sit on top of the spring...

Here is a picture of mine with the 18" wheels.

http://www.corvetteforum.net/c4/mikez40/

[pig_iron]

Thanx for the info. I did decide to go with 18x12 rears from Budnik. I found the set of lowering bolts from Mid America, and they're relatively cheap. Can the spring bolt replacement be done by any Greasy Joe at the local Tires Plus store or is it a complex process that needs to be taken on by a ZR1 tech?

[Mikez40]

Thanx for the info. I did decide to go with 18x12 rears from Budnik. I found the set of lowering bolts from Mid America, and they're relatively cheap. Can the spring bolt replacement be done by any Greasy Joe at the local Tires Plus store or is it a complex process that needs to be taken on by a ZR1 tech?

The lowering bolt is very easy to do yourself. Just jack the car up and put a jack stand under the spring near the bolt and lower the car slightly to take the pressure of the bolt, then un-screw it and put the new one on.. Then do the other side.... After you lower the car you will have to take it for a ride to settle it down... If you can change tire, you can change the rear bolts....

[pig_iron]

The lowering bolt is very easy to do yourself. Just jack the car up and put a jack stand under the spring near the bolt and lower the car slightly to take the pressure of the bolt, then un-screw it and put the new one on.. Then do the other side.... After you lower the car you will have to take it for a ride to settle it down... If you can change tire, you can change the rear bolts....[/quote]

Excellent. Would I be better off taking the car to the tire shop and have them do the fronts? Will they know what I am talking about if I have to give them directions?

[Tom]

The lowering bolts are only for the rear. Lowering the front is much more involved. If you haven't already you should get a GM/Helms shop manual for your 91 ZR1, it will show everything involved in installing the parts on both ends of your car. Don't waste your money on Chiltons or other generic manuals.

[Mikez40]

Excellent. Would I be better off taking the car to the tire shop and have them do the fronts? Will they know what I am talking about if I have to give them directions?

If it were me, I would not take it to a tire shop, I would take it to a corvette shop...You can do it yourself, but like was stated above it is a little more complicated. Also you will need to get a 4 wheel alignment when its done...

[rkreigh]

I would just lower the back and see how you like it.

lowering the front involves removal of the front spring and you can't really lower the car all that much anyway as you just remove the spring shims.

if you really want to lower a bunch, consider going to coil over shocks which involves removal of the factory traverse springs. now you can lower or change spring rates to best tune the ride and handling.

lowering the front is more hassle than it's worth IMHO. for just a bit more $$$ you can do the coil overs which makes a more dramatic improvement.

good luck!!!

[runner38]

Hey Mike. I have a 90 that I want to add aftermarket wheels to. Yours look like what I have been looking for. Did you get those from CCW, or someplace else? If you don't mind me asking what did the set, set you back?

Thanks,

[Z Factor]

Hey Mike. I have a 90 that I want to add aftermarket wheels to. Yours look like what I have been looking for. Did you get those from CCW, or someplace else? If you don't mind me asking what did the set, set you back?

Thanks,

Hello and welcome to the forum.:handshak:

While not mandatory, we encourage you to take a minute to list your location so that others here have an idea where you are from. At times members have lived just a few minutes away from each other and found out by seeing the other members city.

As to your question, this is an older thread so you might want to PM him for information.



:cheers:

[runner38]

Thanks, will do.

I will update my profile and all as soon as I get off work today. I have been lingering around here for a couple of years, just never posted anything.