Just noticed that my wife's wheels are different with front and rear. Wheels are 18x8 front with 225/40r18, 18x8.5 rear with 255/35R18. Question is...can I get a set of tires of the same size for all the wheels....and more importantly can they be rotated fully. Anyone done this and is there any clearance issues or rubbing issues? Thanks!

 

Not surprised you just noticed. Lexus’ .5” difference between front and rear for their ‘staggered stance’ is just laughable. Pretty sure you could swap front and rear without issue, although I probably wouldn’t put different widths on the same axle. Not familiar with available tire sizes, but in theory you could split the difference and run the same size on all four corners with the current wheels.

 

If I'm not mistaken, the rear wheels won't fit up front due to the brake calipers, so that would be a no go for front to back rotation.
You could I guess run something like 235 all around, but you still would not be able to rotate them, so even better go with the correct staggered OEM size.

 

Guess the OP can try putting a rear on the front to verify, I won’t be able to try that until next spring when I take the winter wheels back off.

 

I was able to install the wider rear to the front. Didn't notice anything catching or getting in the way. Didn't like the idea of running the 255 in front with the 225 in the rear.

 

Didn’t think there’d be an issue. You could probably run a 235 all around without issue (with either a 35 or 40 ratio, being slightly shorter or taller, respectively). Again, I’d keep the same size wheel on an axle, not that it would actually make any difference.

 

Thanks! I'll probably find 235 or 240 or 245 all around. The rotate pattern should keep me from having different size wheels on the same axle which is probably good practice.

 

Technically you could, but the issue would be that if you made them all the same size and rotated them, you would have one 18x8 in the front and one 18x8.5 on the other side of the front. I'm not a wheel expert but from a similar experience I had, I was told/did research that having different rotational masses on the same axle isn't good for the transmission or the diff. Now, it probably won't blow your diff or transmission instantly but you may see damage over a long period of time. But like you said, as long as you are able to keep track of the rim sizes and don't mistakenly put an 8 with an 8.5 on the same axle then it should be fine but at that rate, it doesn't seem necessary. You'd still be rotating your tires left to right and vice versa. Plus I figure it comes staggered so there must be some advantage/reason as to why they did that from the factory. Personally, I haven't experienced any issues or drawbacks by running the staggered setup and rotating only left to right.

 

i don't plan on having the different sizes on the same axle. thanks though.

 

position -----| tire -----| tire sidewall height
OEM Front | 225/40 | 90mm
OEM Rear. | 255/35 | 89.25mm
Candidate 1 | 235/40 | 94mm
Candidate 2 | 245/40. | 98mm

If you go with. candidate 1, the overall tire diameter is only 8mm bigger, which means it needs 4mm more space for turnning.

Front wheel: 18 x 8.0 +45
Rear wheel: 18 x 8.5 +50
if you put rear wheel in front, that means the wheel would be (0.5 * 25.4 ) / 2 + (45 - 50) = 1.35mm more outwards, and (0.5 * 25.4 ) / 2 - (45 - 50) = 11.35mm inwards.
ONLY if the wheel face design is excalty the same, then you get 1.35mm more clearance for front brake calipers.

For the front tire offset difference: the actual tire would be (235 - 225)/2 + (45-50) = 0mm more outwards and (235-225)/2+(50-45) = 10mm more inwards.

I think it should be ok with candidate 1 at least. This is just my own thoughts, correct the numbers if they are wrong.

 

As long as you keep the tire diameter within a few mm of original, you should be good to go, assuming the wheel offset allows it to clear the brake calipers.

 

I would not suggest putting the same size tire on different width wheels.

If you want to match tire sizes, match wheel sizes as well.
The 18x8.5's do fit on the front though (I've tested it on my car); so you could potentially get another set of 18x8.5's and run 255/35R18s all around.

I'm currently running an aftermarket set of 18x9's with 255/35R18 at all four corners (Bronze Motegi MR131 18x9 +35mm), when these tires wear out I'll be going to 265/35R18 with a 3mm spacer to give the suspension as much room as possible, while keeping the tire inside the fender (but nearly flush). I went with the 255's initially because there isn't much clearance in the front between the suspension and the wheel & tire, could have gone with +40 to be safe and possibly stayed inside the fenders, but it's easier to add a spacer than machine a wheel down, hence the +35.

 

What year/model is the car?
The rear rim won't fit in the front due to the front calipers (IS350 or any 2017+ IS).

Winter set ups are usually 225-40-18 all around (even on the wider rim) and it doesn't have issues but you cannot rotate them if you have the bigger calipers.