Help with wheel fitment

THBuick86

New Member
Joined
Feb 25, 2019
Im looking at some aftermarket wheels and would like some help to see if they will fit without any mods. I have an 86 GN
Fromt 18x8 4.5BS 0 offset
Rear 18x9.5 5.25BS 0 offset
 
If your suspension and brakes are stock the fronts will fit depending on the tire size. If you run a 255/40 tire it will probably rub the back of the A-arm when fully turned and may need to install a 1/4" spacer. If you run a narrower tire you should be fine.

For the rear you will need to use a 1/4"- 1/2" spacer depending on tire size and how the body sets on the frame. If running a 285/35 tire you'll probably want closer to the 1/2" spacer. If running a 275 tire you will more than likely be fine with a 1/4" spacer.

I was going to say yes the wheels will fit, it's when you put tires on them there's a problem, but the 18x9.5 rears with 5.25" backspacing may still touch the frame.

Just for reference I was running 17x8.5 wheels up front w/ 255/40's. The wheels have 4 5/8" backspace and the tires have rubbed the back of the A-arm on the drivers side during an autocross event. A wider wheel pulls the tire away from the frame a bit.

On the rear I had 17x9 (4 5/8" backspace). The SSBC disc brake kit rotors are 1/8" thicker than drums so for stock brakes 4.5" backspace would be what I needed. The 285/40's just kiss the frame (lower rear) with stock control arms and bushings on hard turns.

This is all at stock ride height or slightly lower with saggy springs and no rolled fenders.
Guys do run 275/35 18's on 9.5 wide wheels with 5" backspacing with panhard bars or watts links to limit side to side movement. I'll see how well UMI control arms with poly bushings work for controlling lateral movement.

I hope this helps some.
 
i think the 5.25 back space wheel will clear the frame but not with a tire on it unless you have zero sidewall buldge. even then it will prob be super close.
 
i think the 5.25 back space wheel will clear the frame but not with a tire on it unless you have zero sidewall buldge. even then it will prob be super close.

^^ this, and with axle shift and articulation it will be super super close.
 
I just picked up my new tires.
The 275/35-18 fronts, at rest the sidewall beads measure 10" apart.

The 285/40-18 rears measure 10 3/8" bead to bead at rest.

On these tires any wheel narrower than that will create some sidewall bulge.
 
I picked up some 18x10 wheels for test fitting.
The wheels have a 0 offset and 5.5" backspace.

For the rear I used an 1/8" spacer, and with my thicker rear rotors
equals 5.25" backspacing with stock brakes.

There is 3/8" clearance from the frame with about a 1/4" at the plastic frame plug.
If the tires don't stick out past the wheel and you can control lateral movement it would be very close considering axle shaft movement at the C- clips and articulation due to body roll and terrain.

Now for the photos.

The wheel
IMG_5452.JPG


Clearance at frame towards the front.
IMG_5450.JPG


Down from top
IMG_5448.JPG


Clearance at frame towards the rear.
IMG_5449.JPG


I will be having the 275/35's mounted tomorrow as I'm more interested in fitment on the front.
More than likely I'll mount the 285/35's on the rear for grins and giggles to double check before ordering the 3 piece wheels.

I'll post back when I do.
 
Last edited:
I picked up some 18x10 wheels for test fitting.
The wheels have a 0 offset and 5.5" backspace.

For the rear I used an 1/8" spacer, and with my thicker rear rotors
equals 5.25" backspacing with stock brakes.

There is 3/8" clearance from the frame with about a 1/4" at the plastic frame plug.
If the tires don't stick out past the wheel and you can control lateral movement it would be very close considering axle shaft movement at the C- clips and articulation due to body roll and terrain.

Now for the photos.

The wheel
View attachment 340348

Clearance at frame towards the front.
View attachment 340347

Down from top
View attachment 340344

Clearance at frame towards the rear.
View attachment 340346

I will be having the 275/35's mounted tomorrow as I'm more interested in fitment on the front.
More than likely I'll mount the 285/35's on the rear for grins and giggles to double check before ordering the 3 piece wheels.

I'll post back when I do.
So would I want to go with a smaller backspace on both front and rear. Im looking to do a bigger wheel but the offset and backspacing can be confusing. I also dont want alot if any tire bulge. I def dont want to order wheels and be stuck with them and not fit right. Thanks for the info so far any additional help or suggestions is appreciated.
 
So would I want to go with a smaller backspace on both front and rear. Im looking to do a bigger wheel but the offset and backspacing can be confusing. I also dont want alot if any tire bulge. I def dont want to order wheels and be stuck with them and not fit right. Thanks for the info so far any additional help or suggestions is appreciated.

First of all, what brakes do you have front and rear?

What are the tire sizes you want?

And keep in mind, the bodies set different on the frames. Some set to the left and some to the right, although they can be centered.
 
First of all, what brakes do you have front and rear?

What are the tire sizes you want?

And keep in mind, the bodies set different on the frames. Some set to the left and some to the right, although they can be centered.
Everything is stock. Brakes and suspension all stock but would like to entertain lowering it possibly 2" but am not set on that.
I have found another wheel 18x8 that has +1 offset and 4.5 backspace with 245x40x18 tire would this work on front and rear. I am not very knowledgeable in the wheel market so I apologize for all the questions.
 
No apologies necessary, we're here to help.

The 245/40-18 tire would fit well on the 8" wide wheel, but with the 4.5" backspace they would look sucked in. As in the tires would look like they are under the car, very narrow like a train car or roller skate.

I wasn't thinking, I should have posted this in the beginning.

I found the thread introducing the gbodyparts 18" and 19" GNX wheels and it looks like the optimal wheel width and backspacing are:

4 3/8" backspace for an 8" wide wheel

4 5/8" backspace for a 9" wide wheel

4 3/4" backspace for a 9.5" wide wheel

Those listings are for a stock setup.

You should be fine with the 245/40-18 tire on the front with a
2" drop.
You could run a 275/35-18 tire on a 9" wide wheel in the rear with a 2" drop as well.

I believe Toby had 255/40-18's on the 18x9 wheels on the front with a 2" drop and 285/35-19's on the 19x9.5 wheels on the rear with a 2.5" drop.

Check out this thread. It should help.

 
The Nitto NT05 275/35-18 tire sidewall sticks out past the 10" wide wheel lip an 1/8".

IMG_5462.JPG
 
No apologies necessary, we're here to help.

The 245/40-18 tire would fit well on the 8" wide wheel, but with the 4.5" backspace they would look sucked in. As in the tires would look like they are under the car, very narrow like a train car or roller skate.

I wasn't thinking, I should have posted this in the beginning.

I found the thread introducing the gbodyparts 18" and 19" GNX wheels and it looks like the optimal wheel width and backspacing are:

4 3/8" backspace for an 8" wide wheel

4 5/8" backspace for a 9" wide wheel

4 3/4" backspace for a 9.5" wide wheel

Those listings are for a stock setup.

You should be fine with the 245/40-18 tire on the front with a
2" drop.
You could run a 275/35-18 tire on a 9" wide wheel in the rear with a 2" drop as well.

I believe Toby had 255/40-18's on the 18x9 wheels on the front with a 2" drop and 285/35-19's on the 19x9.5 wheels on the rear with a 2.5" drop.

Check out this thread. It should help.

So how would the 18x8 i mentioned above look compared to the stock GN setup? i like the look of the stock set up i just want a bigger wheel and make it my own. I know the stock wheel is 15x7 with 4" BS (correct).
The wheels Im interested in do not offer a 9" wide wheel only 9.5 with +1 OS which equals about 5.25 BS which thet say will fit.
Thanks
 
So how would the 18x8 i mentioned above look compared to the stock GN setup? i like the look of the stock set up i just want a bigger wheel and make it my own. I know the stock wheel is 15x7 with 4" BS (correct).
The wheels Im interested in do not offer a 9" wide wheel only 9.5 with +1 OS which equals about 5.25 BS which thet say will fit.
Thanks
Any help is much appreciated!
 
I took a break from wheels for a bit.
Let's start with the front. Yes, stock wheel is 7" with an overall width of 8" and a backspacing of 4".

With an 8" wheel that's 9" overall and a 4 1/2" backspace you have 1/2" more on the outside and 1/2" more on the inside which keeps the center of the tire in the same place.
It would be better to go with an 8" wheel with a 4" backspace.
It would be 1" wider on the outside and move the center of the tire out 1/2" for more clearance.

A 245/40-18 (9.6"w x 25.7" tall) would work well.

The fenderwells have more room on the outside of the stock wheels than on the inside. If you move the wheel out 1/2" you can run a wider tire as it's more centered in wheel well tunnel plus giving it a more flush look.

The same goes for the rear as well.
A 9 1/2" wheel with an overall width of 10 1/2" and a backspace of 5 1/4" sets too far in.
A 285/35-18 (11.2" w x 25.9" tall) tire will rub and the wheel will more than likely contact the frame going around corners.

A 4 3/4" backspace would allow axle movement without any rubbing while providing a flush look.

Check out post #1155 by SlickTR.


His rear wheels have 4 1/2" backspacing, but he more than likely has the fender lips rolled.

You can run the wheels your looking at, but be prepared to install longer wheel studs with a 1/4" spacer in front and a 1/2" spacer in the rear.
 
I took a break from wheels for a bit.
Let's start with the front. Yes, stock wheel is 7" with an overall width of 8" and a backspacing of 4".

With an 8" wheel that's 9" overall and a 4 1/2" backspace you have 1/2" more on the outside and 1/2" more on the inside which keeps the center of the tire in the same place.
It would be better to go with an 8" wheel with a 4" backspace.
It would be 1" wider on the outside and move the center of the tire out 1/2" for more clearance.

A 245/40-18 (9.6"w x 25.7" tall) would work well.

The fenderwells have more room on the outside of the stock wheels than on the inside. If you move the wheel out 1/2" you can run a wider tire as it's more centered in wheel well tunnel plus giving it a more flush look.

The same goes for the rear as well.
A 9 1/2" wheel with an overall width of 10 1/2" and a backspace of 5 1/4" sets too far in.
A 285/35-18 (11.2" w x 25.9" tall) tire will rub and the wheel will more than likely contact the frame going around corners.

A 4 3/4" backspace would allow axle movement without any rubbing while providing a flush look.

Check out post #1155 by SlickTR.


His rear wheels have 4 1/2" backspacing, but he more than likely has the fender lips rolled.

You can run the wheels your looking at, but be prepared to install longer wheel studs with a 1/4" spacer in front and a 1/2" spacer in the rear.
So the 18x8 w +1os and 4.5 bs would require spacers on front and rear? Does the +1os move the wheel closer to the frame and this is why you would nee the spacers? If this is correct can you advise a place to get the spacers and studs? Thanks again and hope I'm not to much of a pain
 
No problem,
The -1 offset does move the wheel closer to the frame. An offset of -12 would give you a 4" backspace on an 8" wide wheel and move the wheel out, away from the frame.

A -12 offset on a 9 1/2" wheel would give you a 4 3/4" backspace for the rear.

It's best to use concentric spacers. Most have a built in pilot hub to keep the wheel centered.
I'll have to look for longer wheel stud numbers for you.
 
The dorman 610-323 stud is 1/2' longer and can be used front and rear. They're reasonably priced as well.

 
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