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Technical Discussion

Go Wider With Apex: 18x11 ET40 Square on the GR Supra

Article | 04/22/2022 by Matt Thompson

When we initially began our relationship with the TAPG (Toyota Automotive Proving Ground) endurance racing team, we knew test-fitting and fitment validation would be key parts of our relationship. Their feedback about clearances on the MKV Supra platform proved to be invaluable for validating suspension clearances with both stock suspension and aftermarket coilovers for our 18×10.5 ET38 forged EC-7Rs. Once we knew we would also be bringing a staggered 18” fitment to market with our SM-10s, we asked TAPG to test our 18×11 ET40 rear wheel on the front of their A90 endurance race car to get an idea of what the clearances looked like.

We knew that if these wheels fit up front, they would be ideal for the driver looking to run an extremely aggressive square fitment. The benefits of a square 18” setup on the Supra platform are impossible to ignore. Having identical front and rear fitments would allow our customers to rotate their wheels and tires between the front and rear axles. This promotes even tire wear and ensures that grip levels remain consistent over the life of the tires. The huge increase in front tire tread width also leads to a significant increase in front-end grip aiding turn-in, especially when combined with a track alignment.

After testing this square fitment on TAPG’s track car running MCS suspension, as well as on other customer cars, we’ve added this fitment to our fitment guides and have begun recommending it to customers who are willing to heavily modify their supra. Our condensed recommendations can be found on our GR Supra fitment guide with tire sizing and availability notes. Read on for a more in-depth look at the modifications required and test fitments conducted with these wheels.

18×11 ET40 square EC-7RS with 315/30-18 Nitto NT01 tires, mods required.

MODS REQUIRED

Aftermarket Suspension: Coilovers & select HAS kits with excellent inner clearance are a must. The higher offset required by these wheels means that the front OE suspension configuration simply will not have enough inner clearance because of the OE spring perch and rubber isolator design. For an in-depth look at how the OE front suspension can limit inner clearance, check out our 18×10 ET30 wheel notes. Motorsport-oriented coilovers are preferred, with the most beneficial setups being those that reduce overall front stack height to move the lower perch upwards, out of the path of the tire.

We’ve tested this setup with the HKS Height Adjustable Sleeve kit and it does fit without rubbing with most tire setups. This is a more cost-effective alternative for customers who want to retain the OE dampers, but we have not tested the clearances of every HAS kit on the market.

Pictured: 18×11 ET40 SM-10 inner clearances around front struts with Megan Racing coilovers & 295/35-18 Yokohama A052s

  • Aftermarket suspensions that have been able to run these wheels without spacers up front include but are not limited to:
    • Megan Racing
    • M Factory
    • MCS
    • JRZ
    • HKS HAS (Height Adjustable Sleeve kit)
    • KW DDC

Track Alignment: Significant negative camber is required up front to run these wheels. While they are a direct fit in the rear, -3° of camber in the front should be considered an absolute minimum with most track tires in the sizes appropriate for these wheels. More camber is often required and a setup that can achieve around -3.5° would be optimal for most of the wider tire setups.

Negative camber is beneficial for tire wear on track as well as wheel fitment in this case. Even for cars with direct fit front wheel and tires, additional negative camber aids performance and reduces outer shoulder tire wear when the car is driven hard on track. Increasing negative camber up front should be viewed as a beneficial alignment change rather than simply as a requirement to run wider wheels and tires without rubbing.

Adjustable camber plates are our preferred method for dialing in camber up front on a MacPherson strut-based suspension like the Supra’s, as tipping the strut inwards at the upper edge tends to provide more fender clearance, but we’ve also seen good results with aftermarket arms.

Additional Notes

Full lock rubbing: This wheel and tire setup will likely rub at full lock in parking lots or midway through 3-point turns. The wider front wheels and tires will gently rub non-critical wheel well liners or in some cases aftermarket suspension arms. This will not typically be an issue at speed on the street or track where full lock is less common. An SPL front offset caster rod bushing can be used to reduce rubbing during high-steering lock turns.

Pictured: 18×11 ET40 SM-10 inner clearances with Megan Racing coilovers & 295/35-18 Yokohama A052s

These wheels are not compatible with most of the aftermarket brake duct cooling kits on the market that use hoses to route cooling air to the front brake rotors. The wheels occupy the space through which the hoses would typically route. Confirmed with the Verus Engineering kit.

TIRE SIZES RECOMMENDED FOR THIS FITMENT

These tire notes were taken from our fitment guide. They may not be all-inclusive but should serve as a starting point when selecting tires. Please note: True tire size is not always reflected by the listed size the tires are sold under. Some tire models may run wider or narrower than others with the same listed size. All front tire fitments for this setup will require additional negative camber, with taller and wider tires requiring more camber to prevent rubbing.

APEX Staff Pick: 295/30-18 – A narrower option with great availability. The easiest size to fit of this list, depending on true tire dimensions. • Extreme Performance Summer – Michelin Pilot Sport Cup 2 Connect (240TW), Yokohama Advan A052 (200TW) • R Compounds – Toyo Proxes R888R (100TW), Nankang AR-1 (100TW), Pirelli P Zero Trofeo R (60TW) • Semi-Slicks – Hoosier A7 (40TW), Hoosier R7 (40TW), Toyo Proxes RR (40TW)

Taller Alternative: 295/35-18 – Fans of the A052, look no further. Because of its taller height, this option will likely require more camber despite its narrower width. • Extreme Performance Summer – Yokohama Advan A052 (200TW)

Wider Alternative: 305/660-18 – A shorter, slick tire option providing good grip and slightly easier fitment for those driving on the track only. • Slicks: Pirelli DH

Wider Alternative: 315/30-18 – The widest option we recommend, and possibly the most difficult to fit. Significant negative camber will be required and fender liners may need to be trimmed, depending on the tire model. Tire availability is superb. • Extreme Performance Summer – Falken Azenis RT660 (200TW), BFGoodrich G-Force Rival S 1.5 (200TW), Yokohama Advan A052 (200TW), Nankang CR-1 (200 TW) • R Compounds – Toyo Proxes R888R (100TW), Nankang AR-1 (100TW), Nitto NT01 (100TW) • Semi-Slicks – Hoosier A7 (40TW), Hoosier R7 (40TW), BFGoodrich G-Force R1 S (40TW) • Slicks – Pirelli DHB

TEST FITMENTS & NOTES

We know seeing is believing. Below are various photos with all the specs we have on the cars and tires. This fitment is an aggressive option and we have done our best to document the various setups we’ve seen – both in person and through customer feedback – to help future owners considering this purchase understand what is required.

Nitro Yellow Wheels: 18×11 ET40 EC-7RS Tires: 315/30-18 Nitto NT01 (100tw) Brakes: Stock Suspension: HKS height-adjustable sleeve kit SPL Lower Control Arms SPL Caster Bushings Camber: -3.4° front, -2.4° rear Additional Notes: Minor rubbing noted at full lock

Toyota GR Supra with 18" EC-7RS in Anthracite
Toyota GR Supra with 18" EC-7RS in Anthracite
Toyota GR Supra with 18" EC-7RS in Anthracite
Toyota GR Supra with 18" EC-7RS in Anthracite
Toyota GR Supra with 18" EC-7RS in Anthracite
Toyota GR Supra with 18" EC-7RS in Anthracite
Toyota GR Supra with 18" EC-7RS in Anthracite
Toyota GR Supra with 18" EC-7RS in Anthracite
Toyota GR Supra with 18" EC-7RS in Anthracite
Toyota GR Supra with 18" EC-7RS in Anthracite
Toyota GR Supra with 18" EC-7RS in Anthracite
Toyota GR Supra with 18" EC-7RS in Anthracite
Toyota GR Supra with 18" EC-7RS in Anthracite
Toyota GR Supra with 18" EC-7RS in Anthracite
Toyota GR Supra with 18" EC-7RS in Anthracite
Toyota GR Supra with 18" EC-7RS in Anthracite
Toyota GR Supra with 18" EC-7RS in Anthracite
Toyota GR Supra with 18" EC-7RS in Anthracite
Toyota GR Supra with 18" EC-7RS in Anthracite
Toyota GR Supra with 18" EC-7RS in Anthracite
Toyota GR Supra with 18" EC-7RS in Anthracite
Toyota GR Supra with 18" EC-7RS in Anthracite

Will’s Purple Track Monster Wheels: 18×11 ET40 EC-7RS Tires: 315/30-18 Nitto NT01 (100tw) Brakes: AP 9660 Suspension: Full SPL setup + MCS Camber: Over -3° front Additional Mods: Full build thread + mod list here

Video Link: GR Supra on EC-7RS Wheels

Toyota GR Supra with 18" EC-7RS in Satin Bronze
Toyota GR Supra with 18" EC-7RS in Satin Bronze
Toyota GR Supra with 18" EC-7RS in Satin Bronze
Toyota GR Supra with 18" EC-7RS in Satin Bronze
Toyota GR Supra with 18" EC-7RS in Satin Bronze
Toyota GR Supra with 18" EC-7RS in Satin Bronze
Toyota GR Supra with 18" EC-7RS in Satin Bronze
Toyota GR Supra with 18" EC-7RS in Satin Bronze
Toyota GR Supra with 18" EC-7RS in Satin Bronze
Toyota GR Supra with 18" EC-7RS in Satin Bronze

TheRacersLine White Track Car Wheels: 18×11 ET40 Anthracite SM-10 Tires: 295/35-18 Yokohama A052 Brakes: Stock Suspension: Megan Racing Coilovers & SPL parts Camber: roughly -2.75° front Additional Notes: Single wheel test fitment

Toyota GR Supra with 18" SM-10 in Anthracite
Toyota GR Supra with 18" SM-10 in Anthracite
Toyota GR Supra with 18" SM-10 in Anthracite
Toyota GR Supra with 18" SM-10 in Anthracite
Toyota GR Supra with 18" SM-10 in Anthracite
Toyota GR Supra with 18" SM-10 in Anthracite
Toyota GR Supra with 18" SM-10 in Anthracite
Toyota GR Supra with 18" SM-10 in Anthracite
Toyota GR Supra with 18" SM-10 in Anthracite
Toyota GR Supra with 18" SM-10 in Anthracite
Toyota GR Supra with 18" SM-10 in Anthracite
Toyota GR Supra with 18" SM-10 in Anthracite

Luke’s A90 Track Setup Wheels: 18×11 ET40 Satin Bronze EC-7RS Tires: 295/35-18 Yokohama A052 Brakes: Stock, Circo race pads Suspension: M Factory coilovers & camber plates Camber: -3.5° front, -2° rear Additional Notes: Minor rubbing at full steering lock

Toyota GR Supra with 18" EC-7RS in Satin Bronze
Toyota GR Supra with 18" EC-7RS in Satin Bronze
Toyota GR Supra with 18" EC-7RS in Satin Bronze
Toyota GR Supra with 18" EC-7RS in Satin Bronze
Toyota GR Supra with 18" EC-7RS in Satin Bronze
Toyota GR Supra with 18" EC-7RS in Satin Bronze
Toyota GR Supra with 18" EC-7RS in Satin Bronze
Toyota GR Supra with 18" EC-7RS in Satin Bronze
Toyota GR Supra with 18" EC-7RS in Satin Bronze
Toyota GR Supra with 18" EC-7RS in Satin Bronze
Toyota GR Supra with 18" EC-7RS in Satin Bronze
Toyota GR Supra with 18" EC-7RS in Satin Bronze

Jimy’s 19” square fitment Wheels: 19×11 ET40 Satin Bronze SM-10s Tires: Falken Azenis RT660 275/35-19 Brakes: Stock Suspension: HKS sleeve kit Custom camber bushing for LCA Vorshlag Camber Plates Camber: Front Camber: -3.3° Additional Notes: Owner’s IG: @jimyssi The 19×11 ET40 wheels we sell can also be used both front and rear. Fundamentally this setup requires the same modifications as the 18” setup but is less common because of a few factors. 18” wheels and tires are generally cheaper and lighter weight than their 19” counterparts and our 18” offerings clear most of the performance BBKs and the stock brakes. The 19” wheels can be used by someone looking for shorter and stiffer tire sidewalls or tire models only available in 19” diameter. This is also the only option for some cars running niche aftermarket BBKs with massive rotor diameters.

See all the Apex wheels we offer for the Supra on our website.

Tags
  • Bolt pattern: 5x112mm
  • Fitment type: Hardcore Track
  • Toyota, Supra, GR
  • Wheel design: EC-7RS
  • Wheel design: SM-10
  • Wheel diameter: 18"
  • Wheel line: Forged Sprint Line
  • Wheel line: Flow Formed Evolution Line

Matt Thompson

Matt became the JDM Product Expert at APEX Wheels in 2022. Prior to joining APEX, he worked extensively in automotive sales. As an enthusiast he made the shift from street driving to track driving in order to fully experience his cars at the limit without putting the public at risk. Matt has owned six Hondas (‘94 Integra LS, ‘95 Integra RS, ‘96 Integra GS-R, ‘06 RSX Type-S, ‘95 Civic VX, ‘17 Civic EX-T), two Subarus (‘15 Impreza, ‘22 BRZ), and is likely shopping for the next addition to his stable. When he’s not helping JDM owners figure out the best wheel setups for their cars, he enjoys playing racing video games and indulging his interest in automotive photography. Fun fact: Matt knows every quotable line in The Fast and the Furious by heart.

Have questions about wheels for your JDM vehicle? Use our contact form and ask for Matt.