Nub here on IS. With the different tire size for front/rear, I assume that you don't do rotation. My IS is NOT FSport and NOT 4WD. This car used to be my daughters..

 

Correct. If staggered, no rotation.

 

I rotate mine side to side if the tires are not directional...

 

My fronts are 225/40/18 and the tears are 255/35/18.

 

You can always flip the fronts and the rears to help out with camber wear. Thats what I do with my aftermarket wheels/tires

 

I haven’t had my is250 long and was planning to rotate tires today when I stumbled on this post. Curiousity here what are the side effects of rotating these wheels if they are staggered? I thought mine were the same but after looking just now I’m 225/40z R18 in the front and 255/35z R18 in the rear. Apples and oranges here but on my camaro my rear rims physically have a different offset so the tire has to be dismounted then remounted on rear rim to rotate them. Are the factory rims on these cars like that as well with different offsets?

 

The rim specs are:
Front: 18x8 +45
Rear: 18x8.5 +50
You can't dismount the tires and rotate them as the rim they would go to would either be too big or too small.

 

that explains a lot that I was unsure of and explain why my rear tire is that much wider. What are most guys on here doing in terms of tire maintenance? I was thinking mine were directional but after looking at the outer wall I don’t see the directional arrow. From what I’ve read swapping the tires/rim from left to right doesn’t seem to be a popular option. And thanks for answering that question also.

 

For tire maintenance just check the pressure periodically and get an alignment every couple years, or as needed, or when replacing the tires...not much more you can do than that.

 

I’m curious is there another style rim from the factory that has all 4 identical rims/tires? I honestly love the rims on it so it would take a really good looking one for me to swap just so I could rotate. Although they would likely last a bit longer being able to rotate them so they wear even.

 

The 3IS comes with a few different rims...only the F Sport rims and the optional IS350 rims are staggered. There's another 18 inch and a 17 inch option that are squared.
Personally I like the mesh style 18 that comes in a square setup:

18 inch square

Optional 350 staggered rim

F Sport staggered rim

 

mine are definitely the bottom rim. I like that style by far the most so I probably won’t swap them out for the square set. Do the staggered rims offer any performance in terms of handling? I would imagine there’s some gain since they come on f sport.

 

Do you see "OUTSIDE" imprinted on your tires? If yes, they're usually NOT (uni)directional, and swapping from left to right is OK, but doesn't accomplish a helluva lot.

What about the infamous & wildly popular replacement of OEM lower control arm bushings with firmer ones?

 

There is that too...replacing the lower control arm bushings with the RCF/GSF ones.
Although some people claim to not have the infamous inner tire wear on the front, although a lot do.

 

@lazer yes all 4 of mine have “outside” imprinted on them. I’ve seen a few post about rotating side to side but having to dismount tires from rim to do so. I’m not sure you have to dismount though if the aren’t directional.
Ive also seen a few post on here discussing upgrading lower control arms to a more solid version. I haven’t had my car to long but so far I haven’t noticed to much excess wear on my inner tire. Maybe a bit feathered on the outer part though.