► APEX 18x10 ET30 Technical Notes: Tire Fitment and More

APEXRaceParts

Well-Known Member
Gold Sponsor
Joined
Oct 15, 2020
Threads
29
Messages
347
Reaction score
295
Location
California
Car(s)
GR Supra Sponsor
As our 18" flow-formed wheels have become a popular option for Supra owners looking to decrease wheel diameter, we've been collecting feedback about various fitment options including aggressive tire fitments in taller sizes that have caused rubbing issues with the factory spring perch on the front struts. With new details about both our test fitment and other tire sizes and models from customers, I wanted to create this thread to give Supra owners an idea of what various tire fitments look like on the A90 platform with our 18x10 ET30 wheels and bring up additional points to consider when selecting tires in general.

Background:
Our 18x10 ET30 SM-10 Supra wheels were made to be run as a square setup as well as serve as the front wheel for our staggered fitment with 18x11 ET40s in the rear. If these wheels had been designed purely as a front wheel the ideal offset would be lower to give more clearance around the front strut assembly. We knew a rotatable 18x10 fitment was in demand as well so these wheels needed to be a direct fit in the rear of the car which required a higher offset. As you can see in these images, an 18x10 ET30 sits just within the rear wheel well of the car:

20210723_191006.jpeg
20210723_190955.jpeg
20210723_191044.jpeg

18x10 ET30 SM-10 with 285/35-18 Pirelli P Zero tires front & rear. Front 5mm spacer required for clearance. Photo/Car credit: @nibble

The front OE spring perch within the A90 Supra wheel wells is the limiting factor when it comes to tire clearance with this chassis. The perch captures the lower end of the spring and consists of a metal plate and rubber isolator pad. The portion of the pad that comes into contact with a wide wheel and tire package can be trimmed or allowed to "self-clearance" to gain a few more mm of clearance on the inner edge but the plate would have to be ground down slightly to improve any clearance if the steel perch is contacting the tire. Aggressive tire models that run wide in taller 18" fitments like 275/40-18 can contact not only the rubber isolator on the spring perch but also the metal perch beneath. Here are some images of the strut assembly and perch itself with the potential areas that might experience rubbing highlighted:


Screen Shot 2021-09-29 at 12.57.57 PM.png
Screen Shot 2021-09-29 at 1.00.09 PM.png
Screen Shot 2021-09-29 at 12.55.26 PM.png

Screen Shot 2021-09-29 at 1.02.12 PM.png

This limited clearance with the OE suspension affects the models and sizes of front tires you can run on these wheels as a direct fit. This will also inherently limit your rear tire size if your goal is to run these wheels and tires as a rotatable fitment. There are several options to improve inner clearance that do not involve the tires themselves:
  • Upgrading to aftermarket suspension with better inner clearance
    • Upgrading to a coilover with a smaller overall diameter than the OE spring and perch configuration or a reduced stack height that moves the springs up and away from the tire will improve inner clearance. Motorsport-oriented coilovers like MCS or JRZ will tend to have a more compact design and a slimmer overall silhouette that will maximize inner clearance on most applications.​
    • This is obviously the most expensive option and should be done for improved suspension performance with better inner clearances being a secondary benefit of the upgrade.​
    • Certain HAS (height adjustable spring) kits we've tested have increased inner clearance. We have a customer running an HKS HAS kit with 19x11 ET40 wheels up front without spacers. Not all HAS kits will increase inner clearance though so purchase with care.​
  • Running a front spacer
    • This is the simplest option for customers looking to run taller tire configurations in aggressive models of tire that run wide.
    • Spacers move the wheel and tire package away from the strut and spring perch. 5mm spacers have typically been enough to resolve any rubbing issues with the tires we've seen and leave enough of the OE hubcentric ring exposed to keep the wheels hubcentric and prevent vibrations.
    • Be sure to run extended-length bolts or a stud conversion kit with any wheel spacers.
    • The spacer may move the wheel and tire out enough to create contact between the upper portion of the tire on the outside edge and the fender during heavy suspension compression. This can be dialed out with additional negative camber.
  • Trimming of the rubber isolator pad and grinding of the OE steel spring perch
    • This is the cheapest option but it is also the most invasive for obvious reasons.
    • There is enough rubber material on the outer edge of the strut to remove some of it and grind away a portion of the perch to improve clearances, but this should be done with care.
Tire Data:
While the above alternatives are options, we recognize that the majority of our customers running these wheels are looking for a bolt-on solution with their wheel and tire setup. With that in mind, this section will cover the fitments that we've seen thus far that have either been a direct fit with zero modifications or those that have had rubbing issues and what was done to solve those issues. A brief summary for this section: If you are looking for an easy fitment, tires with shorter sidewalls are the go-to option including most 275/35-18 and 265/35-18 tires. Tire data and measurements are taken from Tire Rack or the manufacturer's website when available.

265/35-18

Tire model:
Hankook RS-4 (200 TW)
Section Width: 11"
Tread Width: Unlisted
Overall diameter: 25.1"
APEX Notes: Direct fit.
RS-4s are known to run wide across their range so most other 265/35-18 tires will have much better clearance than the RS-4 pictured below. Photo credit: Joe McGuigan

Screen Shot 2021-09-29 at 1.33.23 PM.png


---------------------------------

265/40-18

Tire model:
Continental Extreme Contact Sport (340 TW)
Section Width: 11.2"
Tread width: 9.4"
Overall diameter: 26.3"
APEX Notes: Direct fit.
This is another tire that runs wide despite the listed size. This tire clears the OE perch, but is quite close to the rubber isolator because of the taller overall tire package. This is a great option for owners looking to run a taller tire without modifications. Photo credit @Last Lemming
Screen Shot 2021-10-04 at 9.35.35 AM.png
2F74940E-659F-442E-821E-9458565A766F.jpeg

Front wheels pictured are 18x10 ET30, rears are 18x11 ET40. No spacers were used in any of these photos.

---------------------------------

275/35-18

Tire model:
Falken Azenis RT615k+ (200TW)
Section Width: 10.8"
Tread Width: 9.7"
Overall Diameter: 25.6"
APEX Notes: Direct fit.
These Falkens run narrower than the Hankook RS-4s one listed size smaller and have great clearance thanks to their shorter sidewall. Photo/Car Credit: @Evolution

20210921_180336.jpeg

20210804_233128.jpeg
20210805_090055.jpeg

Front wheels pictured are 18x10 ET30, rears are 18x11 ET40. No spacers were used in any of these photos.

---------------------------------
275/35-18

Tire model: Continental Extreme Force
(200TW)
Section Width: 11.1"
Tread Width: 9.5"
Overall Diameter: 25.5"
APEX Notes: Direct fit??*

Customer is running 5mm spacers to avoid rubbing via tire deflection, but setup appears to clear without spacers. Photo Credit: @kyippee

left photo: No spacers. Right photo: 5mm spacers.

ken conti ECF feedback supra clearance 1.jpeg
ken conti ECF feedback supra clearance 2.jpeg


---------------------------------

275/40-18

Tire model:
Yokohama Advan A052s (200TW)
Section Width: 11"
Tread Width: 9.8"
Overall Diameter: 26.7"
APEX Notes: Mods required.
This tire was used for our initial testfit and photoshoots. At the time, we thought they were a direct fit as the cars tested drove fine without signs of rubbing or witness marks on the tire sidewalls, but after a second testfit we noted that the tire touches the rubber isolator and would not be a direct fit. Corrections will be made to our previous posts and we have updated our fitment guide with this new information. 5mm spacers should allow these tires to clear, but they will not be a direct fit. These tires do run wider than many other tire models in this size. Less aggressive tires with narrower section widths may clear without a spacer in this size.

50838980333_1d366a9095_k.jpg
51201112751_5a908151db_k.jpg
Screen Shot 2021-09-29 at 2.10.40 PM.png

Front wheels pictured are 18x10 ET30, rears are 18x11 ET40. No spacers were used in any of these photos.


---------------------------------

275/40-18

Tire model: Goodyear Eagle F1 Supercar 3 (220TW)
Section Width: Unlisted
Tread Width: 9.4"
Overall Diameter: 26.7"
APEX Notes: Mods required.
These tires rubbed the rubber isolator and metal portion of the perch. Based on our test fitment of the A052s in the same size, we suspect that their section width is wider than 11" based on their fitment compared to the Yokohamas despite a narrower listed treadwidth on Goodyear's site. Neither Goodyear's site nor Tire Rack list a section width for these tires, but they are quite wide. Photo Credit: @gcmak, Joe McGuigan.

Without Spacers:


IMG_2959.jpeg
IMG_2960.jpeg
IMG_2991.jpeg


With a 5mm spacer:
with 5mm spacer.jpg


---------------------------------


285/35-18

Tire model: Pirelli P Zero (220 TW)
Section Width: 11.6"
Tread Width: 10"
Overall Diameter: 26
APEX Notes: Mods required.
These tires are the widest size we recommend for the 18x10 ET30 wheels but even with the shorter sidewall, they are not a direct fit. 5mm spacers will be required with most tires in this size with wider tire models requiring thicker spacers. Additional negative camber can help increase outer tire/fender clearance when spacers are used but alignment adjustments aren't always necessary. Photo/Car Credit: @nibble

Without Spacers:

20210720_195029.jpeg
20210720_200527.jpeg


With 5mm Front Spacers:


20210723_190955.jpeg
20210723_182243.jpeg

Isolator wear caused by fitment prior to the addition of spacers.

Alignment notes for this setup:

20210724_132103.jpeg


---------------------------------

Additional Considerations:
True tire dimensions are not always reflected by the listed size the tires are sold under. This is especially prevalent on the higher-performance end of tire sizes as manufacturers seek to bring a tire to market that outperforms the competition. This leads to tires that run wide both on the tread and section width which can result in unwanted rubbing. We often hear from customers who want to run taller 18" tires to match the OE rolling diameter of the stock 19" wheels and tires. While ideally we would like to have a perfect match, the realities of the fitment constraints on this chassis mean that a 265/35-18 or 275/35-18 tire will be a much easier fit overall if you are running the stock suspension. We have customers running 265/35-18 and 275/35-18 square setups with no traction control or stability control issues on the track or street and overall tire availability is excellent in these sizes giving you access to a wider range of performance tire options. The taller tires can be used, but modifications are often required and should be kept in mind when purchasing tires.

51125810738_3edcbd5899_o.jpg
51126712665_26cd5e79b0_o.jpg

275/35-18 Maxxis Victra RC-1s on our 18x10.5 et38 EC-7Rs
Lastly, with the true width of some of these aggressive 275/40-18 tires, a wider wheel is really the more ideal choice for overall sidewall support and tire performance. R compound tires with thick sidewalls benefit from the additional sidewall support a wider wheel provides and 275/40-18 is an extremely common size to see on our 18x10.5 ET38 square EC-7Rs:

51321530232_2095787a95_k.jpg
51322987649_ae5746e748_k.jpg

18x10.5 et38 EC-7Rs with 275/40-18 Yokohama A052s front & rear. 12mm front spacers required. Owner's IG: @tim.onetime

Fitment Feedback:
Our fitment guide has been updated with this tire feedback as we've received it, but we are always ready for more. If you are running these wheels and have additional notes or questions, please let us know in either the thread below or via DM/email to [email protected]. Our fitment guide with notes about tires and additional fitments can be found here.

A huge thanks goes out to the forum members who have worked with us and provided photos and feedback about these wheels already. I've worked directly with many of you and appreciate the photos and feedback. I believe I've attributed photo credit to everyone correctly with these images, but please reach out with any corrections if that isn't the case.

-Tom
Sponsored

 
Last edited:

nibble

Well-Known Member
Joined
May 21, 2020
Threads
47
Messages
1,255
Reaction score
1,141
Location
NJ
Car(s)
BMW, Honda, Toyota
Hi. Tom.

What would be recommended tire pressure for regular street driving on 18" wheels? the reason I ask this, recently I had a student (on track) who brought 2.0. So I had closer look at the car which had 18" stock rim and door panel indicated 34 psi to my surprise. I thought this would be depends on car and 2.0 is lighter but I thought is was more dramatic difference than I expected.

I've been wondering if I should lower the pressure which I wasn't able to do for past few month due to the incident.. but if you can give us some guidance or your opinion, I'd appreciate it.

cheers.
 

Axix23

Well-Known Member
Joined
Nov 18, 2019
Threads
25
Messages
3,069
Reaction score
3,218
Location
GA
Car(s)
NA
I got an even simpler solution, have the new Version wheels have slightly a lower offset and then it should clear the inner lower spring perch. +30 is just too high of an offset for the front of the Supra unfortunately. I would say +22 to +25 would help a lot.
 
OP
OP
APEXRaceParts

APEXRaceParts

Well-Known Member
Gold Sponsor
Joined
Oct 15, 2020
Threads
29
Messages
347
Reaction score
295
Location
California
Car(s)
GR Supra Sponsor
Hi. Tom.

What would be recommended tire pressure for regular street driving on 18" wheels? the reason I ask this, recently I had a student (on track) who brought 2.0. So I had closer look at the car which had 18" stock rim and door panel indicated 34 psi to my surprise. I thought this would be depends on car and 2.0 is lighter but I thought is was more dramatic difference than I expected.

I've been wondering if I should lower the pressure which I wasn't able to do for past few month due to the incident.. but if you can give us some guidance or your opinion, I'd appreciate it.

cheers.
We don't have specific tire pressure recommendations for any particular diameters of our wheels or 18" wheels in general as it's going to depend more on the specific tire that you are running. With street tires run on the track I typically recommend a lower initial pressure to give you margin as the tires get warmer and the pressures rise with bleeding off of pressure if necessary to keep them happy on track (and airing the tire back up after the trackday is done). From what I've seen on the street, mid thirties seems to be the go-to with most tires, but its going to be vehicle and tire dependant. In the case of your student's car I would guess that the difference in weight between the 2.0 and the 3.0 would be the main reason behind the change, but it could also be a difference in Michelin's recommendations based on the smaller diameter.

I don't think any harm will come from experimenting with the lower pressures to see if it changes the handling, but it won't change the inner clearances up front around the strut significantly. If you note abnormal tire wear with the outside edges on either side of the tire tread wearing away faster than the middle section, the tires are likely underinflated.

I got an even simpler solution, have the new Version wheels have slightly a lower offset and then it should clear the inner lower spring perch. +30 is just too high of an offset for the front of the Supra unfortunately. I would say +22 to +25 would help a lot.
+22 or +25 would absolutely help with front inner clearance! It would also move the rear wheels outward for all of our customers running these wheels as a square setup which would put the rear tires much closer to the rear fenders and risk rubbing in the rear with wide or tall tires. Moving to a lower overall offset fixes the problem in the front while creating one in the rear. In our opinion using a front spacer is an easier solution than requiring a rear fender roll or pull in order to get wider/taller tires to fit. Spacers are also easily removable and reversible if you sell the car later on with the factory wheels unlike fender modifications.

You could of course create 2 different offset 10" wheels, one for the front and one for the rear. The problem with this approach is that it becomes even more difficult to manufacture and keep matching sets in stock, and you lose the ability to rotate wheels/tires between the front and rear axles which is a huge part of why people buy the square 10" setup in the first place. If a staggered, non-rotatable fitment is called for, the 10" front 11" rear would be our recommendation.

18x10 ET30 works well with quite a few tires as we noted above and I will continue to update the list with more options as we get customer feedback, but this section can serve as a guide for those considering these wheels. You are absolutely correct in the statement that a lower offset would be better for a front-specific wheel in terms of strut clearance which is why our 19" front wheel is both narrower and has an ET25 offset. But in this case, the 18x10 ET30 is filling multiple roles.

-Tom
 

kyippee

Well-Known Member
First Name
Ken
Joined
Feb 12, 2021
Threads
9
Messages
90
Reaction score
91
Location
Los Angeles
Car(s)
2021 Supra 3.0, 2022 M235
OP
OP
APEXRaceParts

APEXRaceParts

Well-Known Member
Gold Sponsor
Joined
Oct 15, 2020
Threads
29
Messages
347
Reaction score
295
Location
California
Car(s)
GR Supra Sponsor
@APEXRaceParts Any knowledge on whether the KW DDC PNP coilovers for the Supra give enough clearance to run wide wheels/tires? Thinking of 275, 295, or 305 square without spacers on Apex wheels. The springs don't appear to linear - somebody's clear picture here: https://www.supramkv.com/threads/kw-coilover-ddc.6187/post-158724

Link to the coilovers: https://ind-distribution.com/collec...c-plug-play-bmw-z4-g29-toyota-supra-mk-v-jtsc
No direct feedback for this kit on the Supra thus far, unfortunately. It definitely appears to have conical springs which are less than ideal for inner clearance up front, but we've also seen reduced clearance with the lower spring perch on the KW variant lines on the BMW side of things (often the perch is thicker and lower than on other coilovers). I'd have to get clearance feedback directly from a customer or testfit to know for sure, but would advise caution for now especially with our more aggressive 18x10.5 or 18x11 square fitments.

-Tom
 

OneTimeAccount

Well-Known Member
Joined
Jun 23, 2021
Threads
22
Messages
335
Reaction score
253
Location
USA
Car(s)
2021 Supra 3.0 Premium - Turbulance Gray
51321530232_2095787a95_k.jpg
51322987649_ae5746e748_k.jpg

18x10.5 et38 EC-7Rs with 275/40-18 Hankook RS-4s front & rear. 12mm front spacers required. Owner's IG: @timkainu

Thanks for including my photos! However my IG is @tim.onetime if you could edit it.

Another correction would be the tires in that photo; I was running 275/40-18 Advan A052’s and I had Swift lowering springs. While they didn’t rub the spring perch, I did get fender rubbing up front due to the car being lowered. I would think on stock ride height it would’ve been fine.

Very informative post. And I will say the HKS adjustable lowering springs are great for preventing any rubbing up front. plenty of clearance to even run a 315 tire from what I’ve seen.
 
OP
OP
APEXRaceParts

APEXRaceParts

Well-Known Member
Gold Sponsor
Joined
Oct 15, 2020
Threads
29
Messages
347
Reaction score
295
Location
California
Car(s)
GR Supra Sponsor

Thanks for including my photos! However my IG is @tim.onetime if you could edit it.

Another correction would be the tires in that photo; I was running 275/40-18 Advan A052’s and I had Swift lowering springs. While they didn’t rub the spring perch, I did get fender rubbing up front due to the car being lowered. I would think on stock ride height it would’ve been fine.

Very informative post. And I will say the HKS adjustable lowering springs are great for preventing any rubbing up front. plenty of clearance to even run a 315 tire from what I’ve seen.
Both points corrected above. Thanks for the feedback!

-Tom
 

404nd2

Well-Known Member
Joined
Nov 6, 2021
Threads
1
Messages
52
Reaction score
53
Location
Boston, MA
Car(s)
Tesla MYP | 2020 Supra
You could of course create 2 different offset 10" wheels, one for the front and one for the rear. The problem with this approach is that it becomes even more difficult to manufacture and keep matching sets in stock, and you lose the ability to rotate wheels/tires between the front and rear axles which is a huge part of why people buy the square 10" setup in the first place. If a staggered, non-rotatable fitment is called for, the 10" front 11" rear would be our recommendation.
I can totally understand this. It's tough to justify producing a +22/25 when there's a high chance it may just sit on the shelves forever. A front spacer is a good option and you can even get hubcentric spacers from H&R. I've run them before, really high quality and will come with longer bolts/studs when called for.
 
OP
OP
APEXRaceParts

APEXRaceParts

Well-Known Member
Gold Sponsor
Joined
Oct 15, 2020
Threads
29
Messages
347
Reaction score
295
Location
California
Car(s)
GR Supra Sponsor
I can totally understand this. It's tough to justify producing a +22/25 when there's a high chance it may just sit on the shelves forever. A front spacer is a good option and you can even get hubcentric spacers from H&R. I've run them before, really high quality and will come with longer bolts/studs when called for.
In all reality, if we were going to produce a front-specific wheel for this chassis, it would likely be slightly narrower and have a lower offset as we wouldn't need to worry about supporting wider square setups (similar to our 19x9.5 et25). It's something we may look into, but we need to first get our Sprint lines fully launched to give you guys more forged options including 19's and bolt-on 18s.

As you point out, spacers are a good option for the more aggressive tire fitments, but the article also details quite a few options that are a direct fit.

-Tom
 

kappa_md

Well-Known Member
Joined
Aug 16, 2018
Threads
2
Messages
107
Reaction score
207
Location
Manila, Philippines
Car(s)
Toyota 86 GR, Toyota GR Yaris, Honda Civic Type R
Thank you for this guide! I plan to put 265/35/18 with 18x9 ET30 front & 285/35/18 with 18x10 ET38 rear. Adding also 11/14 spacers plus Eibach ProKit springs. My only concern is if I’ll be too low in this setup since the overall wheel diameter also went down & lowered? I’m hoping this won’t have any rubbing or suspension issues as I plan to maintain the electronic damping of the Supra. Appreciate your thoughts on this. Thank you
 
Last edited:
OP
OP
APEXRaceParts

APEXRaceParts

Well-Known Member
Gold Sponsor
Joined
Oct 15, 2020
Threads
29
Messages
347
Reaction score
295
Location
California
Car(s)
GR Supra Sponsor
Thank you for this guide! I plan to put 265/35/18 with 18x9 ET30 frobr & 285/35/18 with 18x10 ET38 rear. Adding also 11/14 spacers plus Eibach ProKit springs. My only concern is if I’ll be too low in this setup since the overall wheel diameter also went down & lowered? I’m hoping this won’t have any rubbing or suspension issues as I plan to maintain the electronic damping of the Supra. Appreciate your thoughts on this. Thank you
In your case, the overall lowering from the change in wheel and tire diameter will only be -9.2mm. Most of the lowering will be coming from your Eibach spring kit: -43.18mm in front, -30.48 mm in the rear.

The front wheel and tire should have quite a bit of inner clearance around the suspension with the 11mm front spacer. The wheel will sit in a similar place on the outside edge compared to our 19x9.5 ET25 wheel and with a slightly shorter tire I think this setup will likely be a direct fit. If rubbing on the outer edge of the fender does occur, a touch of additional negative camber up front would help eliminate it. A 265 section tire is fairly wide for a 9" wide wheel though so the tire may lack sidewall support.

The rear wheel will be just over 3mm more aggressive on the outside edge than our 18x11 ET40 wheel. This isn't a super aggressive fitment, but with the narrower wheel and 1.2 inches of lowering from the springs, the wheel and tire will definitely fill your rear wheelwell visually. I don't think you'll have rubbing issues, but your fitment will basically mirror @nibble's rear setup shown above but 6mm further out. (grey car with the pink decals) Whether or not you get rubbing in the rear will probably come down to the tires you run. Rubbing would be likely with tires that run wider (100/200 tw tires for example).

If you're looking for a less aggressive rear fitment, I would recommend a reduction in rear spacer size

-Tom
 

kappa_md

Well-Known Member
Joined
Aug 16, 2018
Threads
2
Messages
107
Reaction score
207
Location
Manila, Philippines
Car(s)
Toyota 86 GR, Toyota GR Yaris, Honda Civic Type R
Wow! Thank you thank you! Your inputs are spot-on and very much appreciated! Hoping this setup will be a blast to drive. I opted to go for PS4S thus my tire specs for front and rear. I understand the tire wall concern but I think PS4S sidewalls are durable (also base from experience) since these were the upgrades for the Super Sport and should probably hold well for street setup. I’m using this guide also for tire and wheel setup.
1AC0AF55-EF1B-4A5F-AC74-2E7E5EDACC02.jpeg
 
OP
OP
APEXRaceParts

APEXRaceParts

Well-Known Member
Gold Sponsor
Joined
Oct 15, 2020
Threads
29
Messages
347
Reaction score
295
Location
California
Car(s)
GR Supra Sponsor
Wow! Thank you thank you! Your inputs are spot-on and very much appreciated! Hoping this setup will be a blast to drive. I opted to go for PS4S thus my tire specs for front and rear. I understand the tire wall concern but I think PS4S sidewalls are durable (also base from experience) since these were the upgrades for the Super Sport and should probably hold well for street setup. I’m using this guide also for tire and wheel setup.
1AC0AF55-EF1B-4A5F-AC74-2E7E5EDACC02.jpeg
The Michelins will probably be fine on those wheels, but as the chart above shows, the wheel sizes you have in mind aren't ideal for the width of tire you plan on using. The tires will mount on the wheels without issues and probably be safe to drive but if you move to a more aggressive tire model that runs wider in the future, I would recommend wider wheels to better support the sidewalls of the tire.

-Tom
Sponsored

 
 




Top