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I have newBBS RG-R 17x9 42mm wheels for the front and RG-R 17x9.5 38mm wheels for the rear I bought new from BBS 7 years ago, which are still in the box. I have a USDM 94 with FPSpec Ohlins long stroke coilovers. I have around 25 1/4 to 25 1/2" clearance from the fender to the ground with non-rolled fenders. I will do a new alignment, when mounting the tires. The car is a street car with a very occasional track days with about 400rwhp.
My first question is tires and tire size. I was looking at the Continental ExtremeContact Sport 02 as my first choice with the Michelin Pilot Sport PS2 as second choice. Any opinions?
I was thinking about 245/40/ZR17 for the front and 255/40/ZR17 for the rear or a staggered configuration. Or should I go with 255/40/ZR17 all around? Or should I go with 255/40/ZR17 for the front and 275/40/ZR17 for the rear, yet another staggered configuration? The big question here is that the first option should fit without any fender roll or change in ride height. I question the 255/40/ZR17 in the front or the 275/40/ZR17 in the rear? Any thoughts?
Lastly, the alignment specs I should use depending on the tire choices above for these 17" wheels.
275/35/17 are closer to the proper diameter although there are less options available.
Staggered is fine, you may need to change spring rates or swaybars if you need to adjust under or oversteering.
I know nothing really but I've read that equal spring rates f/r like some ohlins have are better suited for staggered setup while a higher front lower rear rates are better suited for squared setup.
I'm moving from 245/40 255/40 to 255/40 275/35/17. Hopefully it fits without rubbing! I may roll the fenders if needed...
Last edited by neit_jnf; Jun 24, 2025 at 10:53 AM.
Thanks for the pics. The TE37s look great especially since with the proper track fitment, a nice aggressive face, and properly sized (not stretched) tires. I like them a lot better than the narrow TE37 options I've seen in the past.
I've been looking at running SCCA TT Tuner 2 and gridlife trackbattle street, I can run 315s and 285s max, respectively. I was planning to run the Vitour p1 which the closest sizes are 275/35/18, 295/30/18, and 315/30/18. 315 might be difficult to fit since the P1s seem to not like a ton of camber, so I'm leaning towards the 275/35/18 initially since it will be easy fit with a track setup, and maybe go up to 295 if like doing SCCA events over gridlife. I did one Gridlife event last year, and it has gotten a bit serious so I'm leaning towards SCCA.
I have been looking into ordering those TE37 18x11 +45 wheels, but I'm not sure where to order them now...any suggestions? Blackhawk Japan shows discontinued on their website, while System Motorsports still have them listed but they are double the price. :-( If they are unavailable, I might have to go with Apex wheels since they have an 18x11 +52 that will fit with some spacers.
Originally Posted by BLUE TII
My update with the 315/30-18 on 18x11 +45.
With eccentric front lower control arm bushing and camber as in last pic the front tire has full compression and full steering lock. The amount of static camber required is NOT for the street and may not be to my liking on track.
But I am going to try it.
The rear tire however is stuck between the rolled rear fender lip and the coilover lower mount/shock body when it is between tucking half to all the rear tire (doesnt get full suspension compression without contact.)
I could roll the rear fender arches more, but the roll will become a pull and show in the cars body lines and I dont like that look.
At minimum I need to make an eccentric rear shock bushing for the rear upper suspension arm.
The rear tire will probably rub the rear seat seatbelt boss as other 314/30-18 enjoyers have found- but its a nice smooth small nub- not an issue. People have smacked it in with a well aimed hammer blow. I will monitor how glazed the tire inner sidewall gets before I resort to the hammer.
295/30-18 on 18x11 +45 requires a fender roll and alignment. Easy mode.
315/30-18 on 18x11 +45 requires a fender roll, eccentric bushings and an alignment. A lot more work. A lot more camber.
Seems the 18x11 +45 TE37 Saga S Plus is discontinued.
Update to my fitment-
made molydisulfide (mds) impregnetad nylon offset rear shock bushings and was able to have rear tires clear rolled rear fenders on compression with 1/2 of available stock rear camber (havent gotten chassis aligned yet for #s).
Mcmaster carr- 8554K36
Slippery MDS-Filled Wear-Resistant Nylon Rod
1-5/8"
cut to length.
92871A379
18-8 Stainless Steel Unthreaded Spacer
19 mm OD, 50 mm Long, for M12 Screw Size
For the inner sleeve.
Drilled offset hole with 3/4" drill bit (in press) and perfect OD for press fit and perfect ID for hand fit of sleeve in bushing.
You can also see the dust shields I made for the aftermarket inner pivot spherical bearings out of camping mat. No idea why this isnt common.
Also used the available rubber boots on aftermarket rod ends- again no idea why this is only done in offroad racing and not tarmac racing.
Last edited by BLUE TII; Jun 30, 2025 at 11:36 PM.
Wheel offset and rubbing question. I bought a set of BBS RS-GT's (used) which are 18 x 8" with a +40 offset. Running them on all 4 corners with 235 40 R18 tires. One thing I have noticed is when I drive into a parking lot with a steep grade the passengers side tire has been rubbing and catching the fender causing it to bend out. Attached are a couple of pics of the car and then the area of concern. I have measured my stock wheels and tires total diameter and used the wheel fitment guide to make sure rolling diameters would be close and they are almost spot on so I'm trying to figure out if it's just the +40 offset on the front that is giving me issues? From what I read through this thread, it really shouldn't even without rolling the fenders, but what do the experts think? Unfortunately the damage is already done and the paint has cracked, but this fender has some knicks and dings that will need to be fixed anyway. Thanks for any input.
Lastly, still on all stock original suspension so could be very worn out if that makes any difference.
Suspension is made to articulate, so anyone saying their fitment doesnt rub because they have stiffer springs just hasnt hit a hard bump yet.
Thats why when fitting my 315s above I wound the springs down till shocks were on bump stops to see what needed to be moved to keep everything from touching the tire.
Imagine finding out it rubs by hitting an expected bump at freeway speeds or above and it shreds or locks up your tire sending you into a barrier or off the road.
Couple factors on your tire catching fender-
Taller 25.4" tall tire vs stock 24.8" tire diameter means there is less suspension travel till tire sidewall nears top of fender arch--
That means less camber gain from suspension stroke.
So a 25.4" tire of same width as 24.8" tire will contact fender easier.
Another factor is camber. Each degree of static camber in your alignment is ~5mm clearance fender to tire.
0 to -1.5 degrees camber will provide good tire wear with only gentle stately driving.
Add camber.
-1.5 to -2.5 degrees front camber will provide good tire wear with performance driving.
Last factor is that ding on top of that fender arch. That pushed the fender lip in from stock position.
Yeah, its all just 1 millimeter to 12mm each, but those factors stacked up against you.
Thanks for the information. Funny, I was looking at the pictures after I had taken them and realized that the lip that was getting contacted was right beneath the ding there so could have definitely pushed the fender downward more. Anyway, I'm about to install all new bushings, coilovers and redo brakes so it'll be going in for alignment after all that. I'll have to see where the camber is and look into rolling the fenders slightly.
Thanks for the input.
Edit:
Just checked the tire size calculator again and I blew it and now it makes sense. I got the tires I selected on such a good deal that I bought them without checking back on the size calculator. Now I remember shopping tires and why I bough the 40 instead of the 35 aspect. Save a buck and pay for it later. Oh well. Live and learn, the hard way sometimes.
Last edited by obeeone420; Jun 30, 2025 at 05:16 PM.
I am stuck stuck stuck. I have a set of wheels that I'm getting conflicting information on.
The wheels are staggered, fronts are 18x9.5 + 15 and rears are 18x10.5 +15. I currently have 255/35s mounted up which are clearly way too large up front.
Am I able to actually fit these with a 235 up front, a fender pull / rolling stock fenders, DFV ohlins, and stock arms? I am told yes if I crank the oem arms to the max. The shop where my car is doesn't believe that. If the arms are the limitation, which full kit are people running these days? Megan racing distributer websites seemed a bit sketchy and the p2m ones didn't seem to have toe links in their product list unless enjuku's website was just being wonky.
You don't need smaller tires, you need wheels that fit (more offset), or wide fenders.
255 square is pretty much optimal for FDs if you aren't aiming for lap times or making huge power.
I just got a new set of wheels on my car on 7's day. I'm running 18x10 +18 offset with 255/35/18's all the way around. I previously had a different set of wheels, RPF 1's on there that were 18x10.5 (same size tire as now). Back then I would get a little rubbing at full lock on the front, nothing on the rear.
My fenders are rolled and I've got Ohlin FP Sports as well. I don't have any other after market arms.
Here are some pics of 18x11 +45 T37 with 315/30-18 Falken RT660. I wound the springs perches all the way down so you can see how tire tucks.
Max front camber plus offset bushing on lower arm
Minimum rear camber (will add)
I going to get those Apex 18x11 +52 wheels for my rx7 since they are readily available. I will run 275/35/18 or 285/30/18 on it depending on the tire. Right now I've got all stock old bushings. Will I need offset bushings or arms to get enough camber? Or are stock control arms with max camber enough (around 2.4° front camber)?
On my Miata, I get over 3° of camber on the front without offset bushings, and that wasn't enough on track for good tire wear. Assuming the same thing for the RX7 needing more camber for the track, I'm surprised there is almost no one here posting about using offset bushings. I was considering the superpro adjustable kit, but I've heard one or two people mention the bushings slipping and the alignment messing up. The NC Miata has similar issues with an offset upper control arm bushing slipping, so eventually Mazda came out with an offset lower ball joint bushing that everyone uses.
18x11 +52 will require 1/4" (7mm) spacers OR suspension work no matter the tires (wheels hitting things).
For rear you would need aftermarket trailing arm with offset front bushing and offset lower shock mount bushing.
In front the wheel will rub the lower arm at full steering lock.
Auto-xers run adjustable front upper arm or offset bushings (shorter upper arm) for 4-5 degrees neg camber which also brings the bottom of wheel away from lower arm and allows 18x11 50mm offsets without rubbing at lock.
I did the offset (longer) lower arm as that is what is available in pillowball style bushings for the same effect.
Most FD owners dont race competitively, so they arent trying to add front camber.
But there are many threads by the few FD racers on offset bushings and adjustable front upper control arms.
Use "rx7club" and your search term in google because the forum search engine is useless.
Kevin Doe
hpprx7
jkstill
Those racers and more will have threads on offset bushings and adjustable arms.
For both my fitments I would recommend spherical metal bushings as the amount of grip really moves upper control arm poly bushes forward and backward (and this toe changes) when racing.
Love the 18x10 setup!
