I see people saying get +30-40 offset but that's not concave at all. What's the lowest people go for on 3IS?

 

I went with 18x9 +32 on the rear of mine, it has a decent concave appearance without sticking out past the fender.

 

Well ****ty wheels won't be concave. Most Rays/Work wheels are x9.5 +38-45 with plenty of concave. 8-8.5 won't be concave unless you go +20-25 offset which is stupid. Wheel width plays a major role.

 

Offset is just offset if the overall dimensions of the rim is unknown.
You could fit a 19x10 +45 (on the rear) and that could look concave...but really depends on the rim design.
It could be a single piece rim, or two piece rim, or three piece rim.
It could have thick spokes the reduce the concave appearance, it could have thin spokes that curve a lot to increase the concave look.

 

We've done many 3IS with +32-38 offsets that have achieved that deep concave look. Going off what Sasnuke said, there are many factors that determine how the wheel will look once mounted on the car.

 

That wheel looks hot af!

 

To get maximum Concave, you should get a wheel that has 'Middle Concave' or 'Deep Concave' spoke design option. However, you may find that the required offset is only available in a Middle Concave Face.

For example, see the WORK Wheels Zeast ST1 sizing chart below ..
1. The front will need Big Caliper in front for factory IS300/350 or with aftermarket BBK. This will have a smaller lip and smaller concave. (If you have IS250 you might be able to fit a Standard Disk and/or Middle Concave)
2. The rears usually will maximize Concave AND Rim Depth (lip).
3. The lip depth is shown next to the offset in brackets: "(x)"
4. By adding camber, you may be able to reduce the offset enough to bump up your Concave Face or Lip size. ("aggressive fitment")



PRO TIPS:
- You will see that a 19x9.5" (H Disc / Deep Rim) +44-25 has a 54-73mm lip, which is exactly the same lip size as a 19x10 with 51-32mm offset (54-73mm lip). There seems to be a huge misconception that you need wider wheels to have better wheel-to-fender fitment or maximum lip.
- You should also compare availability of tires in your desired wheel size. You will probably find out that 19x10" wheels have extremely slim pickings for tires.
- The ideal tire widths are usually the factory FSport tire width, but you want to make sure the tires are specifically recommended to fit your wheel size. Using a tire beyond the manufacturers safety recommendation are considered "stretch tires". Factory widths are usually the minimum width you would ever want to run to maintain braking and traction ability. By widening the wheels and not the tires, you will have a more pronounced wheel/lip with maximum clearance which is a more pleasing look.

For an IS350 FSport with this particular wheel (assuming no additional camber added), I would recommend:
- 19x9 +32: T Disc - Big Caliper / Semi Concave
- 19x9.5 +40: H Disc - Deep Rime / Medium Concave)


Contact Me for fitment questions and/or pricing on AIMGAIN or WORK Wheels ..

AIMGAIN: https://www.topendmotorsports.com/le...heels/aimgain/

WORK Wheels: https://www.topendmotorsports.com/le...n/wheels/work/


Taking it to the extreme limits, suspension and fitment guru brand T-Demand, maximizes concave and lip depth by using special low-profile Big Brake Kits, along with their specially designed suspension components that increase camber and sometimes even add more inner wheel clearance.

 

I was looking to get a squared set up of 18x8.5 +35 offset , would those fit on a 2016 Is200t?

 

Yes that will fit without rubbing

 

Thank you so much, and wow didn’t think you guys would be the ones replying to my question, I’ve actually been on your guy’s site to purchase some things for the Lexus soon

 

By the numbers it should fit, but ultimately spoke design with dictate if the rim clears the caliper.
I had a 20x8.5 +35 rim that did not clear the IS200t/300/350 caliper simply due to the design of the spoke.
Chances are you will be fine though.