Autocross & Track tires that fit Subarus...
 

I figured we could move this discussion.

One of the biggest challenges we have with our Subarus is finding tires that are the right profile and compounds for the track and autocross.

And while there are multi-use tires that will work at the track and at autocross, there are compromises with them.

Lets start with sizes.

For most of us, we are looking for a 17" tire that will fit a 17"x7.5"-8" wheel. So this means we are most likely looking in the 225-245 width range (255 and even 275 may be possible but really want a wider rim.)

So for sizes we have
205/55-16 (Std WRX OE size)
225/45-17 (Std STI OE size, reference) [Good choice and shold fit without clearance issues]
235/40-17 (2.3% smaller) [Better gearing and shoud fit]
245/40-17 (1% smaller) [About as big as will fit most. May require a little fender massage]
245/45-17 (2.8% larger) [Not really a good choice IMHO]
255/40-17 (.2% larger) [Fenders may need more than just a massage to make these fit]

Now we have tires...

Autocross ST legal tires. Size ($price),... [Sources]

Bridgestone Potenza RE-01R: (Proven Championship Autocross tire in STS)
225/45-17($173), 235/40-17($183), 245/40-17 ($198), 245/45-17 ($200) [TireRack]

Falken Azenis RT-615: (Proven Championship Autocross tire in STX)
225/45-17($108), 235/40-17($119), 245/45-17 ($117), 255/40-17 ($127) [Vulcan, Discount, Edge]

Yokohama Advan Neova AD07: (Proven Championship Autocross in STU)
225/45-17 ($186), 235/40-17 ($197), 245/40-17 ($218), 255/40-17 ($225) [Vulcan, TireRack, Discount]

R compound Autocross only

Hoosier A6: (Proven Championship Autocross tire)
225/45-17 ($219), 245/40-17 ($225) [TireRack]

R compound Multi-Use

Kuhmo Ecsta V700: (An OK but not exceptional tire)
245/40-17($195) [TireRack]

Kuhmo Ecsta V710 (Almost as good as the A6, but size is not great.)
245/45-17($177) [TireRack]

Kuhmo VictoRacer (A classic performer)
225/45-17 ($165), 245/45-17 ($157), 255/40-17 ($172) [TireRack]

Nitto NT-01 (New unknown)
225/45-17 ($164), 245/45-17 ($174) [Discount]

R Compound Track


Hoosier R6 (Insanely sticky but short life)
225/45-17($219), 245/40-17($225), 245/45-17 ($225) [TireRack,

Toyo Proxes Ra1 (pretty sticky and lasts...)
235/40-17 ($172), 255/40-17 ($167) [Edge


There are other brands and tires, but bang for your buck and pure outright performance, these are the common competitors... I'll add them if somebody wants them.

So what does this mean... For Autocross, you are pretty much stuck with $200+ Hoosiers to be competitive on race tires, or $1?0 615s for Street Tires.

For the track you have lots more choices, though you really can't beat the RA1s for bang for your buck. The 615s can also be run at the track and hold up pretty well.

With the exception of the Hoosiers that effectively start as "shaved", you will get better performance in the dry if you run the tires at 4/32" or less to start by having them shaved. This will not significantly decrease tire life as they will likely wear more evenly.

What are the pros and cons for running 235/40-17 versus 225/45-17 on the street and at autocross?

I was thinking about going with 235/40-17 Azenis RT615s when my current set wears out next season, but I need to keep in mind that I usually leave my race wheels on the car over the entire event weekend (they go on thursday or friday evening and come of monday evening). I have a relatively mild alignment (1.3F 0.8R) and already have a bit of rubbing in the rear while on course.

235s will definitely help your gearing on the 2.5. If you are already rubbing, it is time for fender massage or wheels with a higher negative offset if there is clearance on the inside.

On the street they will be fine. Speedo will be off a little and it may hunt a hair more than the 225s, but not much.

I would reccoemd the 235s if you are willing to do something to eliminate the rub.

I will be trying these next year: Bridgestone RE-01R

I'd definitely be willing to roll the fenders a bit if I can find someone experienced to give me a hand when the time comes. I'm on stock struts, so I'm not sure I have much room left to try to tuck a tighter offset in.

Also, is 17"x7.5" adequate for 235s or will I want to find a set of 17"x8" wheels?

Added to the first post. At least at nationals though, it only appears to have done really well in STS. What is interesting is how good the Yoko did in STU... Might be worth the couple extra bucks for them if you want to spend almost twice what the 615s are worth.

what do you guys know about the Yokohama A005 slicks?

I have 235/40/17 Bridgestone S03s (which are supposedly wide for their size) on 7.5" rims and they fit just fine. I wouldn't go looking for wider wheels just to run 235s, unless you plan on going wider in the future.

Not much other than that they are a non-DOT competition race tire.

Legal only in Prepared and Modified autocross classes.

Cool, thanks :)

I would guess that on an RS the 235/40's will rub *less* than the 225/45's. Because they're so much shorter, they should have more clearance than the 225's even though they're wider.

Can anyone w/ 235's on an RS confirm this?

When you say RS, are you talking about a GC RS or 02 and up? I haven't really noticed any rubbing except around very hard turns, but I did that with 225/45 tires as well.

I only ran 235/40s on my 8.5" Volks, and that was also post-flare. But, if I (still) had another one, I would put 235/40R17 on 8" wheels with the expectation that they would fit with just pulling the inner rear fender strip, and letting the fender "self-roll." We'll see how accurate my estimation of this fitment is when I put 235/40 RE-01Rs on my 17x7.5 SSRs with a +50 offset on the OBS, which should have identical fender clearance as an RS. However, I think any 225/45 should fit as well on a given wheel. It's probably a finely split hair to decide which one fits more easily. Most RS guys will go with 235/40, because wider+shorter=better.

The '02 and up gets the same clearances as the WRX of the same model year, so I would guess he means the GC/GM/GF.

13.3 E. States no race tires may be used.




Damn.

These are actually down to $162 at tire rack.

The 225/45/17's are $138 right now.

It looks like Toyo is discontinuing the RA-1. The replacement will be the R888. I haven't found any prices yet but a few people on NASIOC have tried them and claim that they are grippier than the RA-1 was. Some links:

Official web page
List-o-possible sizes und release dates

What we need to watch for is closeout pricing on the RA1s!!! Some sub $150 RA1s would be sweet.

Yeah, cheap Ra1's would be great. I had good luck with them on the track.