Same story with the Federal 595 RS-R's. I have 255/40/17's on my Evo IX and they're meaty as hell. A lot wider than the Nitto NT05's I was previously using. I'd venture to say they're almost as wide as some brands 275's

595rs-r has a tread width of 9.1" for a 255/40/17
BFG Rival has a tread width of 9.5" for a 255/40/17
Direza ZII has a tread width of 10" for a 255/40/17

Granted, these are manufacturer numbers...

The A6 285/30/18 is the same as the 295/30/18 in the same manner that the 255 is the same as the 275.

The R1S 285/30 appears to be about half way between a A6 285/30 and an A6 315/30.

If you can fit a 285/30 R1S, you are a minor offset increase and fender pull away from a 315/30 A6 (by my expectations).

Where did you find this?! I just looked up three tires and found much different info. for 255/40/17 the RS-R has a tread width of 10.2 inches, the rival also has a tread width of 10.2 inches, and the ZII has a tread width for 10.3 inches.

you're looking at the section width, not the tread width.

I'm in the market for some rpf1's and am planning on tracking my car. My question is What is the best setup for this? I am looking at 18/10 +38 with A meaty fitment. I have no problem rolling my rears, pulling and relocating my bumper bolt.

I know I will need A 5 or 10 mm spacer in the rear to clear the trailing arm and 20 mm in the front?

Bumping this thread up as Im looking to step up to wider wheels. I love my 17x9.5 +38 NT03 but with lack of wide street tire sizes I think 18's may be in my future.

As such Im trying to figure out how much it is going to suck to fit 18x10.5 +30 NT03

Tires will be Zii 285/30 and then eventually 280/30 A6's down the road. But for now lets focus on what it would take to fit these wheels with 285/30 zii's and go from there.

How much work is involved in fitting these wheels?

My car is stock bodied and the rears are currently rolled pretty well. No fenders mods on the front and my fender liners are pretty torn up as is so they will either be removed or replaced and massaged with a heat gun this time around.

Im guessing the rear will need a pull as well as the bumper bolt relocated? Relocating the bumper bolt seems easy enough so that's fine. As to the pull how aggressive of a pull are we talking? I'm hoping my car wont look like ass when its done.

I have stock trailing arms and do not want to purchase the modified links. I will clean up the casting flash and trim the abs bracket. But Im guessing with the +30 I should have sufficient clearance at the expense of needing additional work with the rear quarters.

My fronts fenders are untouched currently. I'd prefer to maintain the stock look so I would prefer to not use the "Evodave" kit but am not opposed to it if need be. Cutting is plausible and doesnt appear to be that difficult.

What do I need to know about clearance in the front? I see a couple of you are using a 25mm spacer up front but something tells me that's merely for widening the front track relative to the rear and not so much for fitment. Is that correct or are their caliper/ strut clearance issues?

I understand that every setup is different depending on ride height alignment etc. so I dont need an exact answer. At the end of the day I am going to need to physically mount the wheels and see where it hits and go at it. But I would like to know what I am getting myself into prior.

It can be done.
Personally I think pulling the **** out of the rears look like ass.

If I wanted to stay "stock" body id pie cut the rear fenders and get metal added to create a nice flair.

For the front id get EVO X control arms and the +1 PSRS to move the wheel forward a bit. or just do one or the other. This will help from having you hit the firewall when you turn.

Well yeah that's the thing I dont really want to hack up my car. Im hoping with some effort and patience it can be done and look proper.

From my research thus far it appears that fitting an 18x10 +38 RPF-1 and 285/30 is pretty straight forward so if all else fails I can go that route. But I prefer NT03's and having a wider wheel is also preferred. But if it is significantly more difficult and is going to require more money then I wont bother.

Swapping in evo x front controls arms requires some custom fab work which I am not interested in doing right now.

The car is on Ohlins DFV's with 8" springs and isnt too slammed. I have the offset PSRS as well as Ciro Design Racing Camber/Caster plates.

My last alignment was Camber -3.5F -1.7R Caster 6.1 and 0 toe all around. I have a TRE built rear diff so I may dial in some additional camber which should also help tuck things under the rear fenders.

Im on a fact finding mission right now so I know what Im dealing with. I am not a body guy nor a mechanic for that matter. Just a weekend warrior who enjoys working on his car as well as racing it.

FYI on 18x10 +38 RPF1's, with a 265 R1 tire, 5mm spacer, and -2 camber you only have about a mm of space to that rear trailing arm.

Hope that helps. To be honest I have found you need to just do it as everyone has there own thought of what "works".

Thanks for your feedback. There are a couple guys on here that I saw are currently running the 18x10 +38 RPF1's paired with 285/30 Ziis. I think the front required like a 20mm spacer and the rear was something like a 5mm.

Street tires are most certainly going to be narrower that r-comps or slicks I know. But I suppose a little polishing of the rear trailing arm isnt the end of the world as long as I grind smooth anything that could cut into the sidewall.

18x9.5 RPF1's with 285/30 A6's was the "standard" setup for years for a lot of auto-x folks so the 18x10 shouldnt be that much more difficult. Plus the extra width will help with sidewall squirm and may help keep the tire from rubbing the trailing arm.

That is sorta my "backup" plan as I would really like to get the 18x10.5 NT03's to work. Just not sure how much $ and time Im willing to throw at it to make it work.

I appreciate your assistance. I believe fitting a 285/30 even a hoho will still be easier than your 275/35 since its not as tall, but I could be wrong.

But since we aren't comparing apples to apples here as you said its not a perfect science so the only way to truly know is to test it myself. However there are still a couple things where the type of tire and size wont even come into play.

For example you said the wheel needed a 20mm spacer in the front to clear the caliper as well as the coilover. What coils do you have? My Ohlins have a 2.5 OD x 8" spring and I dont think they are stiff enough such that I could go down to a 6" without having problems.

It sounds like the front fender mod is a must unless I have my front totally reshaped.

As for the rear it is interesting to hear that you didnt have to pull it. I wonder if that is more dependent on tires than anything else?

Its known that the BFG R1S is wider than the A6's so I wonder how much more work is involved in fitting those relative to the A6's? And to that extent knowing that the Zii's are even narrower than the A6's they should require even less work. That's not to say that it'll be easy to fit these as I know it won't but I suppose it does give me some confidence

Professional awesome as of recently is selling the r/t Ernie rear trailing arms. Not cheap but probably worth it.

damn 6.1 caster? was only able to squeeze out 4.7 with my ciro plates at neg 3.6 camber, are the psrs really adding that much more??

Nice pieces no doubt about that but I cant justify that cost right now.

I will have to look back at old alignment printouts but IIRC my stock caster figure was 3.6 and then the CDR plates yielded another 1.5 degrees which put me around 5.1. Finally this past winter I installed the PSRS and that yielded another 1 degree resulting in my final 6.1 degrees of caster.

Anyway, raced both Saturday and Sunday, the car felt really good but my tires are so beyond cooked it's not even funny. I have 1 more auto-x this Saturday and then Im done for the season :(

With no work yesterday thanks to Columbus day I had some time to throw in a set of longer studs in the front in preparation. I still need to pick up another set for the rear.

So one of the guys I race with owns a body shop so I was picking his brain over the weekend. He is confident we can pull the rear quarters ~.5" without it looking terrible. What Im trying to establish is how much of a pull was needed for those who have fit these wheels so far?

GTA- You mentioned that your rears are just rolled flat. Is this with your current 275/35 slick? And you are on the stock trailing arms, correct? Im guessing the +30 is helping keep those away from them which is a plus.

Up front I wonder if a 25mm spacer would be better since I run .5 degree more camber than you?

What's conflicting to me is that some are talking about a really large pull in the rear and others have gotten away with a good roll. I have no plans to run the wide BFG at least for another couple of years so say the widest tire I'd be fitting is the 285/30 A6's roughly how much of a pull is needed?

I have the Ciro plates and PSRS and I'm sitting at about 6.5 degrees right now.