Alright so I have been reading a number of threads on the great wheel and tire offset debate. I read a thread over on the NASIOC page that a Tire Rack representative had posted and he basically said this:

Width .... Offset

6.5" ....... +53 to +55
7.0" ....... +50 to +53
7.5" ....... +47 to +50
8.0" ....... +43 to +47

+/- 2mm for all offsets will reach "wheel nirvana"

So i would be led to believe that for a 8.5" rim one would want around a +40 offset wheel. So I guess I would need to know what the clearance is between the 205 OEM rubber and the stock coil over along with the clearance of the rubber and the inside of the fender well to determine what the safest width tire is. Does anyone have this information?

From eyeballing it I would say that there is about an inch on the inside and about 2 inches on the outside. So i would want to probably leave the inside clearance alone and maybe use a total of an inch and a half of the outside clearance or increase the tire width to a safe 235 or a tight squeeze of a 245. But alas, all tire manufactureres deviate in the inflated width of their tires. I have been looking at the Falken Ziex ZE-512 Maximum All Season Performance Tire, but I don't know how much their tires deviate when inflated. Add to that the changes of width of an inflated tire when coupled with a 7" rim when compared to a 8" rim. I really wish someone had a list of of what tire widths/wheel width/offset would work on the WRX sedan. So annoying!!! ARGH.

I know their are plenty of posts about what size tires are "safe" to use with the WRX sedan, but what about when you are trying to maximize tire width... Why maximize tire width? Because I like the look of wide tires of course Which can be traced back to my initial car infatuation: 70's muscle cars.

Anyways I have decided that I want a 17" wheel and probably as wide of rim as possible to minimize sidewall flex. Which would probably mean an 8" or 8.5" wide wheel. Unfortunately, there is a very small selection of wheels in this size, so it has made me think about stepping down to a 7.5" wheel to increase my selection. I've got the "suggested offsets" along with their margins of adjustment. And I have finally decided that I want the above listed Falken tire. Now all I need is some knowledgable, kind, generous, etc. soul to figure out what is the widest Falken tire that I can fit on a stock WRX sedan using a 7", 7.5", 8" and 8.5" wide wheel while staying within the recommended offsets and not rubbing on the inside or outside. Sound simple enough ?

Anyways, any help or suggestions would be greatly appreciated. And who knows, maybe we can answer a whole lot of other people's questions. I have seen posts of people going from 225 to 245 without having rubbing issues but these have been with a different tire than what I wanted to use.

Thanks again.

 

Luke (from TireRack) didn't post that. It was a moderator from the forum that did.

 

Then do you know if this wheel offset information reliable?

 

Ideally, you want to stick with the stock offset. You want the extra width of a wider wheel to be distributed evenly toward the inside and outside. If you change the offset, the additional width will be biased to one side. This can change handling characteristics as well as load angle on the bearings. However, it's not always possible to keep the stock offset when going with a large width and you run out of clearance. The trick is to stay as close to the stock offset as possible in these situations.

Having said that, I personally have 17x8 Ronals with an offset of -40 and 225/45/17 Pirelli PZero Neros. The wheels come out to the edge of the wells. This looks great, but I really should have gone with a higher offset (I still have room between the strut and inside of the tire). Try a search to see what others are running (offset) in the size wheel you're looking for. That should give you an idea of what offsets will fit.

I still think the "wheel bearing" concern is a highly debateable subject. I've seen plenty of folks who have run offsets close to mine (or lower) with no ill effects.

- Kean

 

The info on the post looks correct to me. I'm kinda stuck in the same situation as you. I want the widest tire possible, but from what I have read the widest you can use with the stock suspension set up is 17x7.5 with an offset of 47-50 and tire of 225 width (with out messing up you milage counter) and to avoid rubbing. Alot of of people have posted that if you wanted wider tires 235 or 245 you would have to change your suspension (coilovers or struts and springs) and also possibly roll your fenders.

 

There are several folks running 235's with no modifications to their cars. As for rolling the fenders......it depends.

17x8's with a 225/45/17 is almost identical to the rolling diameter of the stock wheel/tire set up. I can run 235's if I wanted to, but the 225's fit perfect. Also, I would probably need to change to a 40 series on a 235 to keep the ronlling dia. in check.

.......size varies by tire manufacturer/construction as well (i.e. not all 225/45/17's are created equal.....some are a bit wider than others).

- Kean

 

I apologize if someone has asked this before.

Will an 18x7.5 wheel with +42 offset works on 2002 wrx wagon?

Thanks,
Bernie

 

Not without rolling. 7.5" any lower than about 50mm offset with 225 width tire will hit rear fender liner.

 

I have 18x8 w/ 35mm offset and 225/40/18 tires and they fit without rolling.

 

.....on a wagon?

 

No .. Its a Sedan

 

Judging by the way my 17x8 +40's fit (225/45's), I would say a +35 would most likely rub without rolling your fenders (or serious camber adjustment).

curious......why are you going with such a low offset? Personally, I would stick with one as close to stock as possible (+55).

 

Well Everyone says that the way the berings are set up on subarus that they will fail if you stray too far from the stock offset. But as far as I can tell its just a theory .. Ive never heard of this actually happening.

We probally have about the same clearance (225/45/17's are about the same size as 225/35/18's) The 40/18's in my origional post was a typo.

 

yeah......although I don't doubt the load exerted on the bearings is increased, I've talked to several other people running similar offsets to ours who reported no issues. ........the effects it may have on the dynamics of handling is a different story. Hindsight is 20/20.