What is the widest rim ,I can run on the front of my 87 Grand National?

[blackgn231]

Starting to look like I bought rims I can’t use I put washers on the studs to try to see how far out they need to come and even at a 1/2 it still is hitting the tie rod end . I thought a little bit would make it work but nope . Other then trying a wheel adapter I don’t know what to do . The back spacing is to deep in the back .

 

[1986 Buick GX1]

I'm thinking out loud here. Help me out.

If you use the same backspacing as the factory rim, and the overall diameter of the rim and tire combined is the same as factory, then it shouldn't matter how much wider you go towards the outside of the wheel well as long as maintain the factory backspace and total diameter. No?

I know if the wheel sticks out too much it will end up looking like Joe Dirt's ride . But It would seem like almost 2 inches can be gained this way before the wheel, when positioned strait ahead, is flush with the wheel well trim molding. No?

You have the right idea.
In most cases, with stock A-arms you can add 3/4” on the inside as well, that way you can add 1 3/4” to the outside and have a 9 1/2” wide wheel that doesn’t hit the top inner fender well.

 

[1986 Buick GX1]

You right it’s a 6 something I might not be able to use these wheels. Would take a 1 adapter to make it work and that’s a maybe .

I apologize to keep asking, what is the exact measured backspacing?
You can install 3” long wheel studs and use machined aluminum spacers (not the cast ones) to get the right spacing.

 

[blackgn231]

I apologize to keep asking, what is the exact measured backspacing?
You can install 3” long wheel studs and use machined aluminum spacers (not the cast ones) to get the right spacing.

I apologize to keep asking, what is the exact measured backspacing?
You can install 3” long wheel studs and use machined aluminum spacers (not the cast ones) to get the right spacing.

your right about it being over 6 on backspacing will give you exact when I get home . So your saying going with long wheel studs and spacer is better then using a wheel adapter ? I called I can get a adapter to fit my hug and still have bolt pattern to fit the wheel . This would not be better not sure myself since I have no experience with adapters .

 

[1986 Buick GX1]

your right about it being over 6 on backspacing will give you exact when I get home . So your saying going with long wheel studs and spacer is better then using a wheel adapter ? I called I can get a adapter to fit my hug and still have bolt pattern to fit the wheel . This would not be better not sure myself since I have no experience with adapters .

Relying on quality steel wheel studs is safer than questionable aluminum wheel adapters available on eBay these days.

 

[1986 Buick GX1]

your right about it being over 6 on backspacing will give you exact when I get home . So your saying going with long wheel studs and spacer is better then using a wheel adapter ? I called I can get a adapter to fit my hug and still have bolt pattern to fit the wheel . This would not be better not sure myself since I have no experience with adapters .

Relying on quality steel wheel studs is safer than questionable aluminum wheel adapters available on eBay these days.

These are 2.5” long (1” longer than stock) and will work if you only need a 1” spacer.



Maybe Turbo6inKY can assist with part numbers he uses.

 

[blackgn231]

Thanks everyone for helping with this now just need to be sure about how wide a spacer to get without having longer studs its hard because the wheel wont fit trying to space it out . I am thinking 1 to 1.25 maybe that's all ,I really want to go. Looked at videos showing how to determine how much spacer you can use but they are taking measurements on the stock whhels and spacing the stock ones out so not sure that whay will work more me since mine right now are weld wheels 7 in the front and 8 in the rear.

 

[blackgn231]

These are 2.5” long (1” longer than stock) and will work if you only need a 1” spacer.

View attachment 349384

Maybe Turbo6inKY can assist with part numbers he uses.

Thanks for you help.

 

[1986 Buick GX1]

Thanks for you help.

You’re welcome.
Maybe you can support the lower A-arm with a bottle jack, slide the wheel in to where it just clears everything and measure between the hub and wheel to see what kind of spacer is needed.
You can always PM me if you like.

 

[1986 Buick GX1]

Here are some 3” long studs if needed.


It looks like the stock studs have a knurl size of .501 and the ARP studs are .509 so the holes may need to be filed out slightly for easy install.

 

[mar86gn]

If you have the riken mesh wheels 16x9.5 . We can change the offset to avoid adapters etc. Contact me. Thanks

Sent from my SM-J700T1 using Tapatalk

 

[mar86gn]

Post pics to make sure. Thanks

Sent from my SM-J700T1 using Tapatalk

 

[blackgn231]

If you have the riken mesh wheels 16x9.5 . We can change the offset to avoid adapters etc. Contact me. Thanks

Sent from my SM-J700T1 using Tapatalk

I will have to think it not sure I want to put that much money into these wheels. but I do have 2 questions are these wheels aluminum or chrome? And what type of lug nuts do you use on yours?

 

[1986 Buick GX1]

I will have to think it not sure I want to put that much money into these wheels. but I do have 2 questions are these wheels aluminum or chrome? And what type of lug nuts do you use on yours?

Any tapered seat 12 mm x1.5 lug nut will work.
I like GTA style with the black plastic caps. I’m not sure if that’s what’s used on the GNX, but I think so.

82-92 CAMARO Z28 FIREBIRD TRANS AM LUG NUTS AND COVERS BLACK SET OF 20 (40 PCS) | eBay

Fits: 1982-1992 Chevrolet Camaro / Z28 / RS / Berlinetta / IROC Z. SET OF 20 NEW CAMARO / FIREBIRD 12 X 1.5 MM LUG NUTS AND LUG NUT COVERS. 1982-1992 Pontiac Firebird / Trans Am / Formula / GTA. Set of 20 lug nuts with outside threads and 20 screw on black lug nut covers.

www.ebay.com

McGaurd makes some locking lug nuts that work with the plastic caps.

Cone Seat- Under Hub Cap Wheel Lock Set (M12 x 1.5 Thread Size) - Set of 4 Locks and 1 Key

Cone Seat- Under Hub Cap Wheel Lock Set (M12 x 1.5 Thread Size) - Set of 4 Locks and 1 Key

shop.mcgard.com

 

[TireFryer]

You may not have done this with it yet:

I know this is an old thread but I’m trying to get into autocross at college and local circuit racing. Looking at getting some 18’s to put some track tires on. Can I get an 18x9 or so on the front with like a 255 tire? 18x9.5 rear with a 255/265

 

[1986 Buick GX1]

I know this is an old thread but I’m trying to get into autocross at college and local circuit racing. Looking at getting some 18’s to put some track tires on. Can I get an 18x9 or so on the front with like a 255 tire? 18x9.5 rear with a 255/265

A 255 tire on a 9” wide wheel for the front and 275 tire on a 9.5” wide wheel for the rear is an easy fit. The backspacing depends on your brake setup and how much they push the wheels out.
Even rear disc brakes add a 1/4” per side. The C5 brake upgrade for the fronts add a 1/4” per side and some brake kits add even more.
Aftermarket A-arms on the front allow more room on the inside.
Spindle upgrades can push the wheels out as well.

What is your setup?

 

[Turbo6inKY]

I know this is an old thread but I’m trying to get into autocross at college and local circuit racing. Looking at getting some 18’s to put some track tires on. Can I get an 18x9 or so on the front with like a 255 tire? 18x9.5 rear with a 255/265

18x9 in the front with a properly measured custom offset is probably the biggest you can go trouble-free.

18x9.5 and a 275 wide tire or bigger and you'll likely end up with complications. I did.

 

[TireFryer]

What is your setup?

stock suspension with adjustable shocks and bigger swaybars

 

[Chuck Leeper]

Here's a sample!

 

[1986 Buick GX1]

stock suspension with adjustable shocks and bigger swaybars

With stock suspension and brakes I had 255/40-17’s on 8.5” wide wheels (4 5/8” backspacing).
With tire flex on the Auto X there was some slight rubbing on the back of the lower A-arm at full lock.
With a 9” wide wheel, 4.5” backspace, a 255/40-18 would clear fine.
If you go to a 9.5” wide wheel, a 4.75” backspace would be needed to keep a 275/35-18 tire off the top of the fender.

Changing the upper ball joints to 1” taller upper ball joints will give you a better camber curve for more grip in the corners as well.