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Maximum Wheel and Tire Width Fitment Guide for the FD

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Maximum Wheel and Tire Width Fitment Guide for the FD

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Old 04-16-18, 11:11 AM
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Originally Posted by JazzyFD View Post
Hey guys I recently picked up some SSR Long Champ Vip Wheels from my buddy Circuit Theory. I need some help with tire sizing for a stockish 3rd gen. The wheel specs are 18x8 fronts 18x9 rears all with a +35 offset. And suggestions on tire sizing and Fitment would be greatly appreciated.
225/40-18 up front is best fit on wheels and for wheel lip and fender liner clearance. In back you may have some options, but 235/40-18 looks like the best bet there. 245/40-18 could work, but significantly taller. 245/35-18 could work but then you'd have front tires bigger in diameter than rears, which looks goofy... 255/35-18 might work, but getting kinda wide on +35 if fenders aren't rolled. Some negative camber would help there.
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Old 04-16-18, 01:06 PM
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If you're going to decrease the offset save yourself the hassle....roll the front fenders. I had 17 x 8 +34 wheels, with 235 x 45 x 18 tires, (stock is 16 x 8 +50 with 225 X 50 x 16 tires). the FD was lowered about 3/4 inch. Backing out of a driveway caught a fender....not good!

Rolled front fenders = peace of mind.
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Old 04-16-18, 01:38 PM
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If you're going to decrease the offset save yourself the hassle....roll the front fenders. I had 17 x 8 +34 wheels, with 235 x 45 x 18 tires, (stock is 16 x 8 +50 with 225 X 50 x 16 tires). the FD was lowered about 3/4 inch. Backing out of a driveway caught a fender....not good!

Rolled front fenders = peace of mind.


+1

Front fender lip roll is easy to do without messing up your front fenders.

One catch of the unrolled front fender lip on the tire can lead to damage that can't be undone as it kinks the sheetmetal.
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Old 04-16-18, 02:05 PM
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Originally Posted by Greg Sabol View Post
If you're going to decrease the offset save yourself the hassle....roll the front fenders. I had 17 x 8 +34 wheels, with 235 x 45 x 18 tires, (stock is 16 x 8 +50 with 225 X 50 x 16 tires). the FD was lowered about 3/4 inch. Backing out of a driveway caught a fender....not good!

Rolled front fenders = peace of mind.
235/45-18?! That's about 1 1/2" taller than stock! And you were lowered 3/4", no wonder you caught a fender... I think that 225/40-18 (stock width and diameter) on +35 should clear unrolled fenders, especially with some negative front camber dialed in which IMO is a good idea for handling anyway.
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Old 04-16-18, 02:24 PM
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Originally Posted by ZDan View Post
235/45-18?! That's about 1 1/2" taller than stock! And you were lowered 3/4", no wonder you caught a fender... I think that 225/40-18 (stock width and diameter) on +35 should clear unrolled fenders, especially with some negative front camber dialed in which IMO is a good idea for handling anyway.
You missed the info......they where 235 x 45 x 17's not 18's....Like Blue said....it's easy to roll the front fenders and doesn't mess anything up .....one curb or driveway turn-in and it'll cost much more to fix a front fender.

I've got 18 x 8 +40 with 18 x 35 x 255 fronts.... rolled front fenders....no problems.
18 x 9.5 +40 with 18 x 35 x 275 rears, rear fenders not rolled.

This set-up kept the rolling diameter close to stock.

Last edited by Greg Sabol; 04-16-18 at 02:25 PM. Reason: added info
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Old 04-16-18, 03:28 PM
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Originally Posted by Greg Sabol View Post
You missed the info......they where 235 x 45 x 17's not 18's....
I didn't miss it where you said "235 x 45 x 18 tires"! I did miss it where you said 17x8 wheels...

Like Blue said....it's easy to roll the front fenders and doesn't mess anything up
It often results in distorted/deformed wheel openings. Mine were professionally done by a good body shop and they're still not perfect.

.....one curb or driveway turn-in and it'll cost much more to fix a front fender.
Well, I was running 255/40-17s on +40 offset with very little camber, at 24.75" front ride height, I did tweak both unrolled front fender lips very slightly, no real damage. So I had them rolled. 225/45-17 tires have the same sidewall height but are 30mm narrower, so tire is 15mm further from the fender lip. Subtract 5mm for +35 offset vs. my +40 offset and you have a whopping 10mm more clearance than I had. That's plenty, should never touch the fenders at normal ride heights, particularly with some negative camber (like -1 or more negative).

I've got 18 x 8 +40 with 18 x 35 x 255 fronts.... rolled front fenders....no problems.
18 x 9.5 +40 with 18 x 35 x 275 rears, rear fenders not rolled.
I wouldn't run 255/35-18 on 8" wheels anyway... 225/40-18 would be a better fit on the wheel and give +15mm more clearance to the fender lip.
For the 17x8 +35 and 18x8 +35 front wheels kensin and JazzyFD have, I'd go 225 tires (225/45-17, 225/40-18) and not bother with rolling fenders.
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Old 04-16-18, 04:59 PM
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Originally Posted by ZDan View Post
225/40-18 up front is best fit on wheels and for wheel lip and fender liner clearance. In back you may have some options, but 235/40-18 looks like the best bet there. 245/40-18 could work, but significantly taller. 245/35-18 could work but then you'd have front tires bigger in diameter than rears, which looks goofy... 255/35-18 might work, but getting kinda wide on +35 if fenders aren't rolled. Some negative camber would help there.
With that suggestion will the tire maintain a meaty look. I would like a tall sidewalk that matches front to back.
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Old 04-16-18, 07:50 PM
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Originally Posted by JazzyFD View Post
With that suggestion will the tire maintain a meaty look. I would like a tall sidewalk that matches front to back.
Best fit and sidewall height match on 18x8 fronts and 18x9 rears is 225/40-18 fronts with 255/35-18 rears, which I *think* should fit in back with unrolled fenders, but again, negative camber helps and is a good idea anyway for handling. Very close on sidewall heights, BUT check the dimensions for the specific tire you're choosing. Just noticed that Hankook RS4 225/40-18 is much taller than others for some weird reason... *IF* you ran RS4s, you would want 245/40-18 rears to match the sidewall height of 225/40-18 fronts.
Tire Rack website has dimensional data on most tires, check there to be sure.
What kinda tires are you considering, and for what usage?
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Old 04-16-18, 08:19 PM
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Originally Posted by ZDan View Post
I didn't miss it where you said "235 x 45 x 18 tires"! I did miss it where you said 17x8 wheels...

It often results in distorted/deformed wheel openings. Mine were professionally done by a good body shop and they're still not perfect.

Well, I was running 255/40-17s on +40 offset with very little camber, at 24.75" front ride height, I did tweak both unrolled front fender lips very slightly, no real damage. So I had them rolled. 225/45-17 tires have the same sidewall height but are 30mm narrower, so tire is 15mm further from the fender lip. Subtract 5mm for +35 offset vs. my +40 offset and you have a whopping 10mm more clearance than I had. That's plenty, should never touch the fenders at normal ride heights, particularly with some negative camber (like -1 or more negative).


I wouldn't run 255/35-18 on 8" wheels anyway... 225/40-18 would be a better fit on the wheel and give +15mm more clearance to the fender lip.
For the 17x8 +35 and 18x8 +35 front wheels kensin and JazzyFD have, I'd go 225 tires (225/45-17, 225/40-18) and not bother with rolling fenders.
thank you so much for the information.
my wheels are 17x8 +35 and 17x9 +38
Not 18s lol. But i get the point tho

so 225 40 17 front with -camber and 255 40 17 in the rear
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Old 04-17-18, 09:23 AM
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Originally Posted by kensin View Post
thank you so much for the information.
my wheels are 17x8 +35 and 17x9 +38
Not 18s lol. But i get the point tho
so 225 40 17 front with -camber and 255 40 17 in the rear
225/45-17 front with 255/40-17 rear for same sidewall height, stock tire diameter.
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Old 04-17-18, 02:30 PM
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Hi Guys,

I'm going to be purchasing some wheels in the following sizes

​Front - 18x9.5 +45
Rear - 18x10 +40

What are the max tire sizes I can run for the front and rear? I was thinking either 275/40/18 or 285/35/18 Rear but I don't have a clue about the front. I don't mind rolling the fenders a little but certainly no pulling etc

I'm looking at a few tires but the Michelin Super Sport and the Continental Extreme Sport are looking like winners at the moment.

Last edited by 7_rocket; 04-17-18 at 02:51 PM.
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Old 04-17-18, 04:39 PM
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Originally Posted by ZDan View Post
225/45-17 front with 255/40-17 rear for same sidewall height, stock tire diameter.
if im retaining stock diameter and side wall height, wont it rub on the front since i got +35 offset ?
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Old 04-17-18, 06:30 PM
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Aggressive 17 in set up that will NOT fit Stoptech brakes.
17x9 +45 Front
17x10 + 38 Rear
Just to confirm, will this fitment require rolled fenders? Car will be on coilovers.


Looking for atleast 9" on front and 9.5 on the rear. Was just wondering how far you can push it out on unmodified fenders.
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Old 04-17-18, 07:17 PM
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Originally Posted by ZDan View Post
Best fit and sidewall height match on 18x8 fronts and 18x9 rears is 225/40-18 fronts with 255/35-18 rears, which I *think* should fit in back with unrolled fenders, but again, negative camber helps and is a good idea anyway for handling. Very close on sidewall heights, BUT check the dimensions for the specific tire you're choosing. Just noticed that Hankook RS4 225/40-18 is much taller than others for some weird reason... *IF* you ran RS4s, you would want 245/40-18 rears to match the sidewall height of 225/40-18 fronts.
Tire Rack website has dimensional data on most tires, check there to be sure.
What kinda tires are you considering, and for what usage?
Honestly I want to run Falken 615k+ or Continental Extreme Contacts
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Old 04-18-18, 09:16 AM
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Originally Posted by kensin View Post
if im retaining stock diameter and side wall height, wont it rub on the front since i got +35 offset ?
I run 255/40-17 on +40 offset, which puts my tire's sidewall 10mm closer to the fender lip vs. 225 on +35. I *barely* tweaked the unrolled fender lips while running very little camber (-0.5° IIRC). With 10mm more clearance, you should be OK even with modest camber (but I'd still run at least -1° for handling). Again, 255/40-17 are the same diameter, same sidewall height as 225/45-17.
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Old 04-21-18, 08:19 AM
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Originally Posted by 7_rocket View Post
Hi Guys,

I'm going to be purchasing some wheels in the following sizes

​Front - 18x9.5 +45
Rear - 18x10 +40

What are the max tire sizes I can run for the front and rear? I was thinking either 275/40/18 or 285/35/18 Rear but I don't have a clue about the front. I don't mind rolling the fenders a little but certainly no pulling etc

I'm looking at a few tires but the Michelin Super Sport and the Continental Extreme Sport are looking like winners at the moment.
Decided to go with 18x9.5 +45 all around.
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Old 04-21-18, 12:33 PM
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Originally Posted by 7_rocket View Post
Decided to go with 18x9.5 +45 all around.
Same inquiry I went through ending in post #536 above.
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Old 04-24-18, 08:32 PM
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Originally Posted by ZDan View Post
I run 255/40-17 on +40 offset, which puts my tire's sidewall 10mm closer to the fender lip vs. 225 on +35. I *barely* tweaked the unrolled fender lips while running very little camber (-0.5° IIRC). With 10mm more clearance, you should be OK even with modest camber (but I'd still run at least -1° for handling). Again, 255/40-17 are the same diameter, same sidewall height as 225/45-17.
hi zdan sorry to keep asking these questions lol
i finally secure a good pair of wheels for the front
17x8 +45 fronts and 17x9 +38 rear
The rear im set on 255/40 the front however still debating on either 235/40 or 235/45. Will either 1 of the tire choice make the front look bulky/fatter than the rear ? Seems a bit goofy...I dont want that. Either same bulkiness or less fat? The car is mostly street driven
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Old 04-25-18, 07:12 AM
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Originally Posted by kensin View Post
hi zdan sorry to keep asking these questions lol
i finally secure a good pair of wheels for the front
17x8 +45 fronts and 17x9 +38 rear
The rear im set on 255/40 the front however still debating on either 235/40 or 235/45. Will either 1 of the tire choice make the front look bulky/fatter than the rear ? Seems a bit goofy...I dont want that. Either same bulkiness or less fat? The car is mostly street driven
235/45-17 is going to be 0.3" to 0.4" taller than 255/40-17, so yeah, slightly taller sidewall and might look more bulky which is a look that I hate on the FD...
You could go with either 235/40-17 which is slightly shorter vs. 255/40, or 225/45-17 which is same diameter as 255. Either of those sizes would be legit IMO.

You can always check dimensions of specific tires at TireRack.com, some run wider and/or taller vs others in the same size.
Of course the most important thing is to pick the best tire make/model for your specific wants/needs/usage.

Last edited by ZDan; 04-25-18 at 07:21 AM.
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Old 04-26-18, 03:39 PM
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Currently running 285/30/18 Hoosier A7 on forgestar 18x10 +50.

Fenders are all rolled.

I want to run 315/30/18 in the rears so can get the power down better.

These wheels would seem to be the correct offset

ROTA P45R3 Wheel (18x12, 5x114.3+20mm, 73 Hub)|Rota Rims|Discount Rota Wheel On Sale

I know the tires can fit under stock Fenders, as Eric Strehlniks has done it with a bit of a fender pull.
(sorry if name misspelled)

the concern is getting the offset/backspacing right so the tire is in the right space.

18x12 +20 is 7.29 inch backspace, which appears just about perfect.

Anything else I should Be considering here?

Please, no anti-Rota posts, cuz I have already researched this.



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Old 04-26-18, 05:19 PM
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18x12 +20 with the 7.29" backspace would be considered conservative on the backspace and normally one would run 7.5" or 7.77" backspace to fit the widest possible tire on the FD.

But 4 years ago when you were considering these same wheels you stated your aftermarket rear trailing arms forced you to push your 7.5" backspace out with a spacer.

https://www.rx7club.com/suspension-w...heels-1072961/

So, I guess you either run +20 offset or you put different trailing arms on/run less toe-in and run higher offset wheel and pull the fender less to fit the tire (though, you will have to order and wait for the higher offset 18x12 because I can't find any off-the-shelf solutions).

Back in the day FD owners went to even greater lengths to fit more tire under the fenders with less fender modification.
People have used offset rear shock mount bushings and offset aftermarket rear trailing arms to enable 8" and more backspace.
One owner went to cantilever rear suspension with the shocks mounted in the hatch.

But at some point there is a bulge in the wheel wells that limits the possible backspace/tire ingress even if you move the rear trailing arm and rear shock, but I think you said in this thread in 2011 that you already pounded that in to fit your 285 Hoosiers on +50 offset.

You might be running too much rear toe and overheating your tires making them greasy/oversteer-y based on your tires being too close to your trailing arms and too close to the inside front unibody with the 285/30-18 Hoosiers on 18x10 +50 wheels as I run 18mm more inboard and wider tires and I clear both frontal obstructions with zero rubbing.

The more tire you have the greater the effect of toe, so if you have upgraded bushings to control the movement you should be able to run low toe-in.
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Old 04-26-18, 06:33 PM
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Thanks for the comments, I forgot about that thread. D’oh.

maybe I should just bite the bullet and install flares.

just haven’t wanted to cut the fenders.
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Old 04-26-18, 06:35 PM
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The proble. Is compounded because I want less camber as well. Currently at -3, want -2.5 or so
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Old 04-26-18, 09:59 PM
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jkstill
maybe I should just bite the bullet and install flares.

just haven’t wanted to cut the fenders.
I 100% understand that. I don't know if I could cut such a beautiful body up. Black is my favorite color FD to look at.

jkstill
The proble. Is compounded because I want less camber as well. Currently at -3, want -2.5 or so
Oh, I hadn't thought of rear negative camber because I am still on stock roll centers and running my FD at monster truck height.
I have minimum negative camber which is -1.2 deg static, but I don't think that will work for you with your stiffer springs and stickier tires. I think you are probably in the right range/shooting for right range regarding static camber judging by how much lean I see on Nationals SSM FDsmin pictures.

Well. I would hook up with someone that has lots of experience rolling fenders and do a little traveling if you have to to get an aggressive roll with pull. I have seen some great results, but one has to have patience and experience to know how much to roll out and how much to pull so you don't get the dreaded buckle in the sheet metal above the fender arch.

I guess if you don't like how the roll/pull goes or its still not enough you can go back and cut it up for arches!
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