Wheel fitment question, 18's on 86 GT vert

[red86vert]

Hi, I've got an 86 GT vert I picked up a few weeks ago. It's having the 5 lug front and rear disc conversion done now. Guy has done several others and assures me the hubs will be in the same place as stock. So I'm going with 18x8 front and 18x9.5 rear. My question is whether the front will fit with 20mm offset/5.3 backspace and the rears at 20mm offset/6.0 backspace? I would rather not roll the fenders but I will if need be. Anyone running something similar and have pics/advice?
PS-I've searched A LOT!
Here are the ones I'm looking at:

[red86vert]

Here is the car as it sits, lowered but not sure what springs/setup.

[erratic50]

How is the conversion being done? Is the point to have 18's for looks or great performance thanks to shorter sidewall, etc?

The only way to convert the front to 5 lug and not change the track width is to use stock spindles rotors for a Ford Ranger or other similar vehicle. Having done one this way initially here is what I know

On the positive side, it's easy and fast- requires no more time or effort than a brake job.

There are down sides to this approach
- 79-86 front brakes on foxbodies are Mickey Mouse- way too small
(87-93 LX sport or GT are marginally better but remain poor compared to newer)
- 79-93 Mustang spindles all use old school wheel bearing designs where the "hats" stick out a long ways- this limits wheel options
- 79-93 mustang spindles have very poor Ackerman design resulting in limited front grip and poor handling

I would go to a 94-95 spindle to solve these shortcomings. Also get
- new stock replacement struts since you are there
- caster/camber plates
- Low friction 94 ball joints
or X2 ball joints if you want to drop the front while addresssing bump steer concerns
- MM bumpsteer kit for SN95 spindle on foxbody
- 1999 GT Baer rotors
-1999 GT dual piston calipers
- 99GT braided hoses
- lmr line adapter for passenger side line
- lmr stock proportioning valve plug
- adjustable proportioning valve
- mark VII master cyl with line adapter
- sn95 rear brakes


If you stay stock width it causes some things to keep in mind in front. A 245/45/17 on an SN95 tribar wheel rubbed like heck on my 86 with ranger rotors. Same wheel and tires fit great with sn95 spindles and 99 brakes. Handling is night and day better too. Effortlessly faster in turns and 10x better braking.

Stock spring and X2 and caster camber plates drops the front end around 1.25-1.5". Drop springs will drop it even further.

[red86vert]

My goal is mostly for looks and a little better handling/braking. It is going to be SN95 up front and Cobra discs in the rear. The guy doing it came highly recommended and has done the conversion many times. He told me the hubs will remain at the same place as stock.

Thanks for that list, I'm going to check with him and make sure he is doing the bump steer kit, ball joints, and caster/camber plates since that was not specifically mentioned. I'm not sure what is already on the car but it is clearly lowered and I like the stance.

[red86vert]

Doing some more searching I found another thread where someone was looking at the same spec TSW's and wraithracing stated that the 20mm offset will not work in the front with SN95 conversion. I will have to talk to my guy again and see how he is going to get the hubs in the same place. Assuming they stay the same as stock with the 20mm work? If not, they offer a 40mm so could I run that with a spacer? Just trying to get this right the first time!

[wraithracing]

Doing some more searching I found another thread where someone was looking at the same spec TSW's and wraithracing stated that the 20mm offset will not work in the front with SN95 conversion. I will have to talk to my guy again and see how he is going to get the hubs in the same place. Assuming they stay the same as stock with the 20mm work? If not, they offer a 40mm so could I run that with a spacer? Just trying to get this right the first time!

I don't recall stating that a 20mm offset would NOT fit up front with the SN95 Conversion, but its possible.

Generally a 19mm or 20mm offset will fit with the 87-93 front brakes and spindles on a 4 Eye. If running the OEM 79-86 brakes, then that offset generally requires an additional 1/8" spacer to clear the strut. All of this is with an 8" front wheel.

The SN95 (94/95) spindles WILL widen the front track width 0.120" per side so basically 1/8" Not a huge amount, but again it does affect things. The 96-04 spindles will widen the track by 0.320" per side, but are not recommended with the stock K member due to bumpsteer issues.

In my experience the SN95 17x8 wheels with the 30mm offset fits very well up front with the SN95. You might be able to get a 20mm offset to work up front with the SN95 spindles, but you are most likely going to have rubbing issues on the fender lips due to the wheel sitting further out on the body.

Yes, if needed you can adjust your wheel positions using spacers. You always want to verify that you enough thread engagement in the lug nuts with the spacers installed to be safe. I also only recommend hubcentric spacers as that assures that the wheels are centered correctly on the hubs/axles and rotate true. Keep in mind that the deeper offset will change the look of the wheel, so that can affect your opinion of them too. Good Luck!

[red86vert]

Thanks Trey, is the 30mm you're referring to good with the 94-95 or the 96-04 SN95? This is turning into more than I had expected. Now it's getting UPR Chrome Moly K member kit and the SVE complete 5 lug conversion. That uses the SN95 (96-04) spindles and I know the hubs will be pushed out a bit. Anyone happen to be running the SVE kit and know what for sure the proper wheels specs are?

[Jack Hidley]

If the rears are 9.5" wide, they will never fit with a 6" back spacing. You are going to need a 6.4" or slightly greater back spacing. It is always easier to add a wheel spacer and move the wheel outboard. It is impossible to go the other way.

[red86vert]

Thanks Jack.

[erratic50]

The 95 17" tribar rims on ranger rotors fit on my car without spacers but it was so close the wheel weights rubbed and I had to go to stickon. Depending upon camber setting where the spindle bolts to the strut it's quite possible it usually won't fit as mine just barely cleared. Agreed on the spacers.


Agreed on the increased width from newer spindles.

Most people suggest simply using fox balljoints with spacers or low friction stock 94 style balljoints.

I chose the X2 to drop the front by raising the spindle on the control arm. X2 reportedly helps with bumpsteer when using stock outer tierod ends. I went with a MM tapered SN95 spindle on fox bumpsteer kit instead as it allows fine tuning.

X2 yields full suspension travel still while having a lowered car which depending upon your needs may or may not be a big deal. It was a huge deal to me.

if I had it to do again I would go 255/40/17's instead of 245/45/17.


in the rear I swapped in an sn95 rearend. IMO it sucks. It's too wide. I'm going back to fox width but using Mosier fox length 5 lug axles with sn95 hubs. Northern racing brackets are needed to adapt the sn95 brakes to the fox width axles.

[red86vert]

Ok so I think I'm close to having this nailed down. I'm looking at 18x8 front with 35mm offset and 18x9.5 rear with 40mm offset. The fronts will have 245/40/18 and the rear 275/35/18. I'm willing to use a small spacer if necessary. Does anyone see any problem with this using the SN95 (96-04) front spindles and standard fox length axles in the rear?

[erratic50]

Tire sizes seem tight but perhaps possible..... unsure.

Offsets look a bit off compared to what I would expect but I'll let others who play with wheels more comment there.

Unless you have an aftermarket K member 96+ spindles in front are TOTALLY wrong. It results in an uncorrectable bumpsteer problem. You need 94-95 spindles in front.

if you want more width in front, newer K members are wider. Also newer 94+ control arms are longer (but watch your spring rates as longer arms have more advantage on the spring in the pocket)

Personally I would leave the width as close to stock as possible as your rub points are usually in front of the wheel on one side and at the frame rail on the other when you turn lock to lock.

Good luck with your build!

[red86vert]

erratic50, yes it will have a new tubular K member and the 5 lug SVE conversion with 4 wheel discs using the 96-04 spindle. That is why I was looking at the higher offset in the front.

[erratic50]

There are few tubular K members that should be considered for use on the street.

Good of luck with your build!

[wraithracing]

Thanks Trey, is the 30mm you're referring to good with the 94-95 or the 96-04 SN95? This is turning into more than I had expected. Now it's getting UPR Chrome Moly K member kit and the SVE complete 5 lug conversion. That uses the SN95 (96-04) spindles and I know the hubs will be pushed out a bit. Anyone happen to be running the SVE kit and know what for sure the proper wheels specs are?

In my experience the 30mm offset has worked with both spindles and Fox length control arms. Yes, the wheels are a bit further out with the 96-04 spindles, but I didn't have any rubbing issues.

I personally am not a fan of UPR products in regards to suspension pieces. I know others have used their products and are fine with them. I personally prefer Maximum Motorsports especially for Daily Driver and Road Racing as I believe they are the best designed and the best built product out there. I know they are not cheap, but you definitely get what you pay for IMHO.

If budget constraints prevent the purchase of MM, then I would recommend looking at Team Z, or AJE before UPR. Again just my opinion and its your money.

[red86vert]

Almost done: BBK ceramic equal length shorties, Flowmaster H pipe and American Thunder with polished tips, tubular K member, coilovers, bumpsteer, CC plates, 4 wheel disc big brake kit (5 lug), Niche Milan 18x8 front 18x9.5 rear on 245/40 and 275/35's.

[Hammer Down]

Any rubbing on the front tires? What k-member? BTW, car looks great with the wheels/brakes combo.

[red86vert]

K member is the UPR Chrome Moly with coilovers kit. No rubbing, everything fits fine. May have to roll fenders when I drop it more idk I'll have to measure and check everything.

[red86vert]

All done, for now lol.

[erratic50]

Looks really nice. I'd have a little concern about the rears rubbing if you don't limit rear suspension travel.

BTW - What did you do with the 4 lug mesh wheels? What are they? I'm doing an 85 Saleen (clone?) build and have been looking at wheels for it.

[red86vert]

Thank you! Yea driver's side rear got slashed a little bit when I hit a deep dip in the road so all fenders got rolled. Didn't want to do that but it was needed, no issues now. The old wheels and tires are sitting in my garage just waiting to put them on craigslist. Not sure of the brand I'll try to check soon but I'm working 13 hour night shifts right now so if you're interested in them give me a day or two.

[erratic50]

Location may be key.... Where are you located?

[red86vert]

Panama City Florida

[wraithracing]

Looks really nice. I'd have a little concern about the rears rubbing if you don't limit rear suspension travel.

BTW - What did you do with the 4 lug mesh wheels? What are they? I'm doing an 85 Saleen (clone?) build and have been looking at wheels for it.

Thank you! Yea driver's side rear got slashed a little bit when I hit a deep dip in the road so all fenders got rolled. Didn't want to do that but it was needed, no issues now. The old wheels and tires are sitting in my garage just waiting to put them on craigslist. Not sure of the brand I'll try to check soon but I'm working 13 hour night shifts right now so if you're interested in them give me a day or two.

Location may be key.... Where are you located?

Panama City Florida

Everything is cool right now, but no further discussion of buying or selling in NON Classified threads. Please take any further communications to PM. Thank you!

[droopie85gt]

Looks like the technical questions are over, but good Lord, that is one fine foureye! If I won the lottery, I'd have a drag car, a dirt track car, a trophy truck, and then I'd have a stable of muscle cars for daily drivers. And one would be a good looking fox convertible.