a few questions about wheels and springs... - ZR-1 Net Registry Forums

pig_iron · 01-24-2005

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 · 01-24-2005

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 · 01-28-2005

Quote:

Originally Posted by 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.

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 · 02-01-2005

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 · 02-01-2005

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 · 02-02-2005

Quote:

Originally Posted by 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?

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 · 02-02-2005

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 · 02-02-2005

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 · 02-02-2005

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?

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 · 02-09-2005

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!!!

01-24-2005	#1
pig_iron Join Date: Jan 2005 Posts: 22	a few questions about wheels and springs... 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.

02-01-2005	#4
Mikez40 Join Date: Feb 2004 Location: Flower Mound, TX Posts: 17	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/ __________________ 1993 ZR-1 #372 Black on Black

02-02-2005	#8
Tom Join Date: Jan 2004 Location: Southern CA Posts: 108	Lowering 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.

02-09-2005	#10
rkreigh Join Date: Jan 2004 Location: Alex VA Posts: 1,087	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!!! __________________ 95 390 LPE ZR1 (505 rwhp) LSV = Lingenfelter Super Vette Twin Turbo 2003 Z06 (800 RWHP)

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01-24-2005	#2
Z Factor Join Date: Dec 2003 Location: S. Florida Posts: 2,667	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.