Help with wheels please
Lexus Test Driver
Joined: Feb 2017
Posts: 6,260
Likes: 1,752
From: Richmond Hill, Ontario, Canada
My first question is .. why do you want extra wide wheels? In most cases it will be more expensive, heavier, has more clearance issues, and in most cases will not influence the rim concave or lip size at all compared to a narrower wheel with a lower offset.
Clearance on these cars is 90% tire contact issues. So the 'tire offset' and tire width are most important.
Are you ok with stretching tires? If not then you will need 235s in the front. 235s on a 19 need about +36-38 offset for complete 100% suspension travel to prevent tire from hitting things in the front fender/bumper area (I'm talking at full compression no matter how low your setup, even air). If your not worried about that, you can prob go 30-38 offset. In the front the wheel itself will prob never hit the fender unless you have wide wheels with low offsets and are completely aired out on air suspension.
Rear will take into play tire width/offset first, but also wheel width/offset as the wheel travels deeper into the body on compression. For me a 19x10 +47 with 265s in back had about 1mm of tire clearance and maybe 6mm of wheel clearance when completely aired out (even if you dont have air, this shows you full suspension compression clearance). With an 11in wide wheel you will be running a 275 tire? If thats the case my math says you will need +52 offset or higher (for 100% full travel tire clearance).
So .. considering 100% suspension travel .. then I would say you should be around 19x9.5 +36 with 265s / 19x11 +52 with 275s.
I'm in the process of changing from 19x9 +32 on 235 / 19x10 +47 on 265 ... to 19x9 +34 on 225s / 19x9.5 +45 on 255. (I have AWD so I had to reduce the rear wheel to fit 255s, just so I could get 225s in front for complete aired out clearance and still maintain the correct tire size/width ratio. No tire stretching.)
In my opinion, you want to start with the narrowest tires possible (factory size). Then from there determine the maximum tire offset possible without rubbing under full compression. From there determine the maximum wheel size for the tires allowed.
The vehicle with TE37s definitely has issues in the rear if they actually want the car to be drivable. They'll be adding a camber kit and/or changing tire sizes very soon. They might even have quite a bit of toe out to prevent the tire from contacting the rear bumper/fender area.
Just my opinion, your welcome to yours. My method focuses on factory suspension arms, and total clearance under all conditions including airred out. If you prefer wider set-ups, and rubbing under some more less common conditions .. then you will and can come up with completely different specs. Tire brand, tire wear, and alignment (camber and TOE) can have a effect on clearance.
Clearance on these cars is 90% tire contact issues. So the 'tire offset' and tire width are most important.
Are you ok with stretching tires? If not then you will need 235s in the front. 235s on a 19 need about +36-38 offset for complete 100% suspension travel to prevent tire from hitting things in the front fender/bumper area (I'm talking at full compression no matter how low your setup, even air). If your not worried about that, you can prob go 30-38 offset. In the front the wheel itself will prob never hit the fender unless you have wide wheels with low offsets and are completely aired out on air suspension.
Rear will take into play tire width/offset first, but also wheel width/offset as the wheel travels deeper into the body on compression. For me a 19x10 +47 with 265s in back had about 1mm of tire clearance and maybe 6mm of wheel clearance when completely aired out (even if you dont have air, this shows you full suspension compression clearance). With an 11in wide wheel you will be running a 275 tire? If thats the case my math says you will need +52 offset or higher (for 100% full travel tire clearance).
So .. considering 100% suspension travel .. then I would say you should be around 19x9.5 +36 with 265s / 19x11 +52 with 275s.
I'm in the process of changing from 19x9 +32 on 235 / 19x10 +47 on 265 ... to 19x9 +34 on 225s / 19x9.5 +45 on 255. (I have AWD so I had to reduce the rear wheel to fit 255s, just so I could get 225s in front for complete aired out clearance and still maintain the correct tire size/width ratio. No tire stretching.)
In my opinion, you want to start with the narrowest tires possible (factory size). Then from there determine the maximum tire offset possible without rubbing under full compression. From there determine the maximum wheel size for the tires allowed.
The vehicle with TE37s definitely has issues in the rear if they actually want the car to be drivable. They'll be adding a camber kit and/or changing tire sizes very soon. They might even have quite a bit of toe out to prevent the tire from contacting the rear bumper/fender area.
Just my opinion, your welcome to yours. My method focuses on factory suspension arms, and total clearance under all conditions including airred out. If you prefer wider set-ups, and rubbing under some more less common conditions .. then you will and can come up with completely different specs. Tire brand, tire wear, and alignment (camber and TOE) can have a effect on clearance.
The writer is speaking from a position of a setup that supports a bagged IS that is able to air out all the way.
In that respect the specs he quoted are in the realm of correct.
If you are at stock height or will lower the vehicle with springs/coilovers (a static setup), those specs no longer apply.
Thread Starter
Driver School Candidate
Joined: May 2021
Posts: 10
Likes: 0
From: Florida
I already purchase my wheels according to the info your first gave me my man 19x9.5 +38 front and 19x10.5 +45 rear thank you it was a pain to find this set up with the specific offset now is just the waiting that’s gonna kill me cause they told me 6 to 8 months to get the wheels here to United States and I’m keeping my suspension stock no air no bags no coilovers maybe in the future just lowering springs…. Also I wanted to ask if you know of any front strut bar and sway bars for the 21 is350F sport thank you again my man your info was awesome help
Lexus Test Driver
Joined: Feb 2017
Posts: 6,260
Likes: 1,752
From: Richmond Hill, Ontario, Canada
I already purchase my wheels according to the info your first gave me my man 19x9.5 +38 front and 19x10.5 +45 rear thank you it was a pain to find this set up with the specific offset now is just the waiting that’s gonna kill me cause they told me 6 to 8 months to get the wheels here to United States and I’m keeping my suspension stock no air no bags no coilovers maybe in the future just lowering springs…. Also I wanted to ask if you know of any front strut bar and sway bars for the 21 is350F sport thank you again my man your info was awesome help
On the 2014-2020 there were some companies that offered them...but I think do to the low demand they were quickly discontinued.
The rear on the 14-20 required the subframe to be dropped in order to swap the sway bar. I think the process turned some off from doing it unless they really needed it.
At the end of the day, better tires, springs, dampers can pretty much give you the same result as sway bars and overall improve the handling of the vehicle.
I wonder if the strut tower spacing on the 14-20 is the same as the 2021...this may mean that bars for the 14-20 could be used on the 21...hood clearance would be the only other consideration.
Rookie
Joined: Sep 2019
Posts: 35
Likes: 7
From: CT
@roger13 I would take the information above with a grain of salt.
The writer is speaking from a position of a setup that supports a bagged IS that is able to air out all the way.
In that respect the specs he quoted are in the realm of correct.
If you are at stock height or will lower the vehicle with springs/coilovers (a static setup), those specs no longer apply.
The writer is speaking from a position of a setup that supports a bagged IS that is able to air out all the way.
In that respect the specs he quoted are in the realm of correct.
If you are at stock height or will lower the vehicle with springs/coilovers (a static setup), those specs no longer apply.
Rookie
Joined: Sep 2019
Posts: 35
Likes: 7
From: CT
I already purchase my wheels according to the info your first gave me my man 19x9.5 +38 front and 19x10.5 +45 rear thank you it was a pain to find this set up with the specific offset now is just the waiting that’s gonna kill me cause they told me 6 to 8 months to get the wheels here to United States and I’m keeping my suspension stock no air no bags no coilovers maybe in the future just lowering springs…. Also I wanted to ask if you know of any front strut bar and sway bars for the 21 is350F sport thank you again my man your info was awesome help
I believe T-Demand has sway bars, but they really aren't needed with the right mods. The best handling I found was from RCF Front LCA's and after-market Rear Member Inserts. I think it's still open whether the 2021 shares the 2014-20 suspension.
Last edited by TOPENDMS7; May 30, 2021 at 01:37 PM.
Lexus Test Driver
Joined: Feb 2017
Posts: 6,260
Likes: 1,752
From: Richmond Hill, Ontario, Canada
Best of luck with your car modding endeavors.
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