18" rim, tire, and backspacing specs.

[1/4MileRacing]

I have a 87 GN and I am looking to buy some 18 x 9 front rims and 18 x10 rear rims. I wanted to see if there were any guys running this set up and if so what are the specs on your set up. I would like to have the rear tire and rim under the fender without any modifications such as notching the frame. My fenders are already rolled so I guess I am just looking for some guidance on tire size and backspacing to get a set up like this to work without any further modifications. Thanks for your help and any input would be greatly appreciated. Also if you have any pics that would be greatly appreciated. I am thinking about 275/35/18 for the rear and 245/40/18 on the front. Have read some other post and saw others recommend the 245/45/18 for front.

 

[xcessiv6]

I do run this setup check out my cardomain site

 

[1/4MileRacing]

Thanks

I saw your car on car domain and it looks very impressive just wondered if you had to notch your frame or do anything to get these to fit I was looking at some American Racing rims and was just trying to do the rim & tire things in the easiest manner. Again thanks for you post and great looking car.

 

[xcessiv6]

no notching plenty of room 18x10 4.75 back 18x9.5 4.75 front space

 

[GNXwannabe]

18 inch Wheels

I have 18x9.5 rears and 18x8.5 fronts NO rubs anywhere. 4.00 back spacing on front and 4.75 on rear. This set up DOES use adapters to get the correct backspacing for the wheels I used. The last pic is with GNX flares on the car. I used a 285/35 Nitto 555 on the back.

 

[GNXwannabe]

Front Tire size.

I noticed that I forgot to mention my front tire size. It is a 245/40.

 

[1/4MileRacing]

Thanks for the info and the pics. I was going to go with the 18x9 18x10 american racing black rebel, but the backspacing is way off so I am back at the drawing board about picking a wheel.

 

[GNXwannabe]

18" options

I used a Ruff Racing wheel. I did have to go a "different" route but ended up with an excellent fit and the car drives great. I actually used a 5x4.5 bolt pattern and since I needed to use spacers to get the correct backspace I used 1.5" adapter/spacers that converted the 5x4.75 stock bolt pattern. I also used this combo on a set of Halibrand 17x8 and 17x9 wheels that I have since sold. They also fit well. The current combo I am using ran me about $1800 complete (wheels, tires, adapters, mount/balance and lugs). I spent a LOT of time milling over the options and IMO the most wheel options are with the 18" size. The 5x4.5 bolt pattern offers an endless choice in wheels. (Mustang bolt pattern) "So many Mustangs so little time!". My car also sits on stock springs. I hope I have been helpful. Good luck finding your wheels/tires.

 

[gbodygmachine]

18x9 and 18x10 with 1" frame notch. Dont know the backspacing because I am running spacers, I just kept maching them down until the wheels fit correctly
Jeff

 

[93FIVEOH]

Gbodygmachine, nice project, I like the progress thus far. Do you know if there is a write-up located somewhere that details what is all involved in the Corvette brake setup you have installed? I have already seen the post w/in this forum about the vendors who supply the parts, but I am actually curious about a detailed write-up about the installation.

 

[xcessiv6]

Hey Jeff love the chrome looks good hope you get it done maybe see you at RTH4.

 

[jdpolzin]

18x9 and 18x10 with 1" frame notch. Dont know the backspacing because I am running spacers, I just kept maching them down until the wheels fit correctly
Jeff

Jeff, what is your suspension set up? I think your stance is absolutely perfect! Love it! ------Jeremy

 

[Tony_SS]

I used a Ruff Racing wheel. I did have to go a "different" route but ended up with an excellent fit and the car drives great. I actually used a 5x4.5 bolt pattern and since I needed to use spacers to get the correct backspace I used 1.5" adapter/spacers that converted the 5x4.75 stock bolt pattern. I also used this combo on a set of Halibrand 17x8 and 17x9 wheels that I have since sold. They also fit well. The current combo I am using ran me about $1800 complete (wheels, tires, adapters, mount/balance and lugs). I spent a LOT of time milling over the options and IMO the most wheel options are with the 18" size. The 5x4.5 bolt pattern offers an endless choice in wheels. (Mustang bolt pattern) "So many Mustangs so little time!". My car also sits on stock springs. I hope I have been helpful. Good luck finding your wheels/tires.

What spacers and where did you get them? Thanks. Wheels/Tires look great BTW.

 

[gbodygmachine]

Gbodygmachine, nice project, I like the progress thus far. Do you know if there is a write-up located somewhere that details what is all involved in the Corvette brake setup you have installed? I have already seen the post w/in this forum about the vendors who supply the parts, but I am actually curious about a detailed write-up about the installation.

I made all the adapters myself. So I dont know how you would install a kit really. It basically consists of a hub and a caliper bracket. Any kit should be pretty self explanatory. And thanks for the compliment.

Jeff

 

[gbodygmachine]

Hey Jeff love the chrome looks good hope you get it done maybe see you at RTH4.

I really hope to make some events this year. I need power steering and a different master cylinder first though. And thanks, I think the chrome wheels were the way to go.

Jeff

 

[gbodygmachine]

Jeff, what is your suspension set up? I think your stance is absolutely perfect! Love it! ------Jeremy

Up front I am running 9.5" 550lb circle track springs with spring adjuster cups, also a circle track part. In the rear I cut out the spring pockets from the frame and installed a cross member that I welded up. I am running a 9" strange coil-over. To the best I can figure the car has been lowered about 4". But the suspension geometry has been corrected via tall ball joints and SCP upper control arms.

Jeff

 

[93FIVEOH]

But the suspension geometry has been corrected via tall ball joints and SCP upper control arms.

So no bump steer at all encountered with that setup? Are you still able to run the stock tie rod ends? Are those tall ball joints in both the upper and lower CAs? Please excuse all the questions, I'm trying to learn here. I know my Mustangs, but not the TRs.

 

[gbodygmachine]

So no bump steer at all encountered with that setup? Are you still able to run the stock tie rod ends? Are those tall ball joints in both the upper and lower CAs? Please excuse all the questions, I'm trying to learn here. I know my Mustangs, but not the TRs.

The bump steer will be fine due to the fact I am using stock spindles with the taller upper AND lower ball joints. From what I have read and been told, I am good with stock tie rod ends (what i'm running) but I could go aftermarket if I ever have an issue.

 

[boostingbuick]

Too bad it can't keep up with my stock height v6.. You need to post some pics of the car show at your house. I will see if I can find mine.

 

[jdpolzin]

The bump steer will be fine due to the fact I am using stock spindles with the taller upper AND lower ball joints. From what I have read and been told, I am good with stock tie rod ends (what i'm running) but I could go aftermarket if I ever have an issue.

Jeff, one other question for ya. Wouldnt using taller upper and lower ball joints cancel out each other? the reason is that I was always under the impression that using just lowers will raise the spindle upperward allowing the bottom of the wheel to travel outward farther under cornering conditions. I'm no expert here but have been doing the best I can to understand out front end geometry. I love the way your car sits. Could you possibly send me a few progress pictures with the set up. I am trying to get as low as possible and would like to learn more about the way you set up your rear suspension. thanks -----Jeremy