OK I need major help as I am getting different answer from everyone I ask. Here is my situation:

I have an '06 IS350 with 18" rims. Looking to get winter tires. I would like to get a 17" non-staggered setup (225 all the way around).

Tirerack tells me that the IS350 MUST have a staggered setup in order to function properly. They say I could go down to 17" staggered setup.

The dealership tells me that the IS350 CAN run a non-staggered setup without problems BUT only in the 18" tires. They also said that the IS350's that come with 18" can NOT run 17" winter tires at all (staggered or non-staggered).

What the hell is the truth? I would like to run 17" 225 all the way around, but I don't know it that would be okay. If that isn't okay then my next question is which would give me more control/grip in snow/ice: 17" staggered setup (225/245) or an 18" non-staggered setup (225 all around).

Need help please. Anyone that owned a 350 last winter want to tell their experience? I've searched this forum and can't fine any answers to my questions.

TIA!!!

Vit

 

I've only had my IS350 for a few weeks, so I can't say for sure, but I think the only reasons you couldn't run 17" and non-staggered are:

1) 17" wheels don't clear the brakes
2) 17" wheels reduce the overall tire+wheel diameter and mess up the speedo. I read that there is an adjustment on the NAV for different tire sizes.

Number 1 isn't true, because the IS350 is the same car with the OEM 17" or 18" wheels. The sport and X packages don't change the brake sizes either. So, as long as the 17" wheels clear the brakes (and have the right offset), there is no reason you can't use them. I'm planning to pick up the 17" OEM wheels for the winter set.

Number 2 I am not certain of, but if you choose a tire so that overall tire+wheel diameter is close to the OEM 18" set-up, you should be fine. For example:

stock 18" rear, 255/40-18: 26.1"
stock 17" rear, 245/45-17: 25.7"
non-stag. rear, 225/45-17: 25.0"

So, you would be better off with the 17" staggered set-up, assuming the speedo is affected.

I would also guess that a 18" non-stag setup (225) would be better for traction than a 17" stag setup (225/245) since the rear tires would be narrower. I don't know if it would be noticeable enough, though, especially to justify the increased cost of 18" wheels and tires.

Someone please correct me if I'm off here.

 

Best traction in the snow and ice is going to occur when you have the narrowest tire possible. Usually when someone mentions the term "staggered", that means that the tires are wider on one of the axles. Obviously, usually the rear, as is the case on the IS w/ 18" wheels. That being the case, I can't think of any reason why you couldn't run a non-staggered setup.

However, the rear tires on the IS are taller than the fronts. And when they say "must use a staggered setup", they might be referring to that. And they would be right. If you can find a 17" wheel that will fit over the 350's brakes, and can find the correct tires sizes, then I see no reason at all why you couldn't go that route. For winter, I would guess that you'd want a set of P225 width tires on all 4 corners. Maybe even P215, if you can find the right size. When I owned my 330i, it had the same (basically) tire & wheel sizes as the IS, and I ran P205 width tires in the winter. Hard to find the right size nowadays, though.

I checked the tirerack website, and it says in bold, red letters at the top "*** Warning: Stagger OD, DO NOT sell same tire front and rear. All models use valve TPMS *** "

Call up one of their sales people and find out why. The phrase "Stagger OD" sounds like it's referring to the "outside diameter".

 

There is really no reason a 17" wheel (that has the correct offset and clears the calipers) wouldn't work.

Is there a reason you don't want to run a staggered set-up? By staggered, I mean 225/45/17 in the front and 225/50/17 or 225/45/17 and 245/45/17.

The issue with running the same diameter front to rear comes from the fact that the computer may be calibrated with those OD's. It may very well be that running the same OD is acceptable as it may be within 'tolerance.' However, you run the risk that VDIM might kick in too early or too late, as the case may be.

I wouldn't take that risk but that's just my .02.

 

The standard wheels for the IS350 are 17 x 8 with 225/45/17 F and 245/45/17 R. Fitting the brakes with a 17" wheel should be a no-brainer.

The optional wheels are 18 x 8 front with 225/40/18 and 18 x 8.5 rear with 255/40/18.

As long as the rear wheel and tire combination is within 3% of the original diameter, you'll have no issues. So a 225/50/17 will be a 0.6% size difference. Well within tolerance for working just fine.

A 225/45/17 is 4.24% smaller than the OEM size. This will not work well. Magic number is 3%. So you'll still need staggered sizes in your snow tires no matter how you look at it.

BTW, stagger is a term often used to describe tires of different overall diameters. They could be F/R or L/R. Oval track cars all have staggered rear tires to help the car turn left, and one of the things you can do to fix understeer on an oval track car is increase rear stagger.

 

Thanks for all the replies. I guess I'm just not that car smart. I thought staggered was referring to the width of the tire and not the height. So you are saying that I can stagger the width OR the height and then it is still considered a staggered setup?

So I can run a 225/45/17 and 225/50/17??

I guess what I am asking for is the smallest rim and the narrowest tire that will work for the IS 350. Can anyone tell me what that would be and what the offset for those tires would be?

TIA!

Vit

 

A set of standard IS350 wheels in 17 x 8 with the tires you listed will work fine. The standard wheels are 17 x 8 front and rear with the same offset. You could almost rotate them if the tires were the same, but since they're not, you just have four identical rims with front and rear tires slight differently sized. You might be able to get those stock sized wheels for a pretty good price if you find someone who bought the stock wheels and upgraded, or find a dealership that did the same. Take-offs are usually pretty inexpensive.

It will look pretty odd, but it should work like a charm.

 

I've got the exact same questions. Did you ever end up with anything?

 

Just make sure you have a higher offset... +43, +45

 

But stock offset is +45front and +50 rear, you mean a lower offset? Or higher than stock? Sorry, tire/wheel newb.