The problem is the parts that need clearancing are "inboard of the vertical plane of the hubwheel mounting face".

 

Ah, okay. So 285's are the limit then. Even with crazy -20 offset they won't sit out far enough?

 

Just an FYI, you can't touch the crash beam in STU so the JDM IX bumper won't work unless you come up with something to work around the fitment issues.

 

having them stick out further in the front makes the problem worse. It increases the amount the wheel swings front/back when you turn the wheel.

In the rear i'd be chopping the fender all the way to the bottom of the door, and still would probably have to increase the rear ride height to make it work.

To do it right we'd end up in SM.

 

good point. I was just going on the stu allowance to change bumper covers.

If that's really the only mod that puts him out of stu, i'd sell that bumper asap.

 

Ah, Okay. Well thanks for the heads up. It saved me some test fitting time. Going with the Daddio setup!

 

I see your point about the spacer issues but why else is 18" 285 so much better than 17" 275's? Please explain a bit more to me if you guys could.

 

There are many issues. One of course is that they have a taller overall height that makes fitment more of an issue. Second, they are still 10mm narrower. Third they have a taller sidewall which has an effect on various things such as transitional response, sidewall deflection, etc. The Evo has a much crisper response on the shorter sidewalled 285's. The one and only reason to go with a 275/40/17 over the 18" setup is cost. The 285 is better in every aspect.

 

The common line of thinking is wider is better. Also, the 18 has a shorter sidewall which should deflect less than the 17.

I did some tire temp tests and I wonder if I am using the entire tread of my 275 let alone a 285. In addition, unless you buy an 18 wheel that is light you are going to add unsprung weight which might outweigh the benefits from the stiffer sidewall.

As far as Hoosier vs. Kumho, the more square profile of the Hooiser reminds me of the Bridgestone vs Michelin controversy in F1 a few years back. Bridgestone protested the Michelin tire which had a more square tire edge which in thier mind was illegal because it created a wider contact patch. In the end IIRC Bridgestone ended up adopting a less rounded/more square tire edge.

 

What size wheel were you using with the 275? If the tire is pinched you will effect contact patch. Also alignment, tire pressures, etc. all come into play. With the right setup you should be using all the tire.
Fwiw, the 285/30/18 V710 is the same weight as the 275/40/17. The Hoosiers are also very close in weight. There are just as many decent weight 18" wheels as there are 17". Actually I think when it comes to wheels in the 10" wide range there are more wheel options in 18" that will work with the Evo.

 

17x9 -3.3F/-1.6R. I am basing my statment on temps taken on the inside edge, middle and outside edge.

The FNO1RC in 18x9.5 weighs 22lbs mine weighs 18.5. Not saying this is the ultimate wheel but it is a solid wheel for a reasonable price. If money is no object it is a different matter entirely! More diameter and more width equals more metal. More metal equals more weight. This is of course not taking into account design and the density of the metal alloy. Personally I would like the wheel and tires that the F1 teams use. I picked one up and the entire wheel and tire weighs like 13 lbs! I almost hit my chin it was so light...

FWIW the diameter of a 285 30 18 is about an inch less than the 275 40 17. This underscores the advantage in fitting these suckers in the wheel wells. The width of the Hoosier sounds like an issue though.

 

Rubbing issues are totally solvable - at least with 18s and 285/30/18s.

I think my Corsas are as big and fat as the Hoosiers but even if they're not you can get everythign to fit with the right spacers.

I finally put on some 15MM H&R jobbies, did a little extra fender modding and now - BINGO!

Here's what I did - same as EVOlutionary's pic but I also did some work on the rocker panels too since the inner edges tend to rub at full lock.

Everything's covered here:


End result is that the front wheels do stick out a little but I've acid tested this setup and I get NO rubbing on the fenders bumps or in corners, NO rubbining on the fenders or the inner fender bodywork (as a result of all the hammering and cutting, particularly the rocker panel mods) and NO problems rubbing the frame in front of the shocks thanks to the spacers - I now get full, clean, lock to lock steering.



Better front traction too - in short - sweeeeeeet!

I think that biger/taller tires (such as 275/40/17s) could also be accommodated by using the same hammering/cutting methods and adding spacers to fit your setup - you may just need a little more or a little less.

I also did a little research on the best spacers to use - apparently the bolt on spacers are better since they don't but any extra stress on your studs like running a slip on spacer + extended lugs would do. The bolt-ons are also supposed to vibrate less than slip ons which I think is important (I added 72.6MM hub centric spacers to fit my particular rims and the car rolls perectly smooth at all speeds now).

Now hopefully this setup will do the trick until I can afford to get some ultralightweight wheels (thinking of Enkei RCT4s since there's a decent local supply).

You guys with the lightweight rims = lucky!!!!!! I tried lifting up an 18.10 inch Enkei RCT4 with a racing slick on it and it seems to weight HALF of what my Rotas do. I can only imagine how nice they'd feel...

Yes, I'm jealous!

 

Same for AS/STU/BSP/SM. Not allowed to remove or replace them . . .

 

Just FYI, everything done here are the back of the wheel well is highly illegal in BSP. . .

 

thats a bummer. do the rules state you can't modify them either?

I have a JDM rear and I've been running in BSP all season. I thought maybe it would put me in SM but where else would I be classed?