2015 WRX auto-x impressions

[mitchman]

Link to where you can download a PDF of the rulebook:
http://www.scca.com/solo/content.cfm?cid=44517

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[SPDboyNY]

awesome thx, I don't know how I missed it

[testarossa28]

Originally Posted by alphaBETA

I've been debating the size thing lately - still can't decide. Probably going to start out on Hankooks. I didn't try the "V2" Hankooks last year, but I loved the old RS3. It kinda feels like butthole with squishy sidewalls pinched on a narrow rim, but the more aggressive you drive the more heat you could get in and the faster they got.

The Z2's are brilliant as they are sticky on the first run, but overdrive them and they drop off - I got to imagine this is going to be an issue on the front of the WRX. The stiff sidewalls make the car feel good, but I'm not convinced they actually work to your advantage outside of feel. Based on wear and grip I was able to use far more tread of the squishy sidewall RS3 than a stiffer sidewall Rival when pinched.

Size options I'm looking at (Going to need a set of wheels too):

245/40/18 - pretty much guaranteed availability in any future tire, but expect paying +$200 a set premium vs 17s. Rims are a bit more $$ too. Probably the best gearing for fast courses.

245/45/17 - Right now Z2SS is the only option I would consider, but I'm pretty sure I won't want to be on Dunlops once it gets warm out. But I know they are capable if I can keep my shtuff together.

235/45/17 - Cheap option and published tread width for the RS3 is only 0.1" less than the 245/40/18. Taller sidewall might be offset by not trying to put too much tire on a 8" wheel.

255/40/17 - Also cheap - not sure how I feel about the gearing, even if its <2mph difference from the taller 18" option. Leaning toward this one at the moment.

This is currently my predicament. Not sure its worth the extra money to go with 18s. Using my stock wheels as snows so I'll need rims. May try to find dine old STI 17 inch ones to stay cheaper.

[ABQautoxer]

I've put a fair number of runs on the Dunlop Z2 star spec, what you know about the old Z2 does not really carry over at all. They handle heat a ton better than the old ones, much more similar to the RS3v2. Also they finally like slip angle.

[alphaBETA]

Originally Posted by ABQautoxer

I've put a fair number of runs on the Dunlop Z2 star spec, what you know about the old Z2 does not really carry over at all. They handle heat a ton better than the old ones, much more similar to the RS3v2. Also they finally like slip angle.

Interesting, you're not making this decision any easier

[epv]

Yea, I'm just becoming more unsure of what the 'right' tire decision is as time goes on. I think I'm to 245/40R17 ZIISS now... but I'm sure that will change tomorrow.

[bunz559]

Going to be running the 15 in it's first autocross and in my first attendance in over 5 years. Hope to have fun and really discover the driving characteristics under load other than daily driving. Will be running on RCE yellows. Wished I could hold off on the install and just it completely stock but I'm just too antsy.

[bunz559]

Ran my first autocross in years on Sunday and had an awesome time. Making baby steps of improvement throughout the runs. Started with 53 seconds with a chill run to learn the course and incrementally dropping it to 48, then 46, then my fastest time of 45.26. I had a hard time feeling out whether the car wanted to stay in first or second gear. Not too happy with my 1 handed driving at the end but I got caught finding gears.

YouTube (Short URL)

YouTube (Short URL)

[wiUFsh]

Great thread guys! I am currently setting my car up to run in STX this year. Since there is a 8" wide wheel limitation and a 245 tire limitation I plan on buying 18x8 +35 TSW Nurburgrings (because they look bada$$ and they are 3 pounds lighter than stock.) I am a little torn on the tire though.

Since the OE Dunlops were 235 I was planning on running that width of tire. After reading this thread I wonder if I should just use the max 245 on there. What do you think? Keep in mind this car is also my daily driver so I think Michelin Pilot SS will be a solid, all around good choice. Thoughts?

[inmledoml23]

8" wide wheel limitation? That sucks.

[wiUFsh]

Up until the 2015 WRX, the WRX fell into the STU category; unlimted wheel width. Now, the 2015 falls into the STX category; 8" wide limit for AWD cars. Yes, it sucks.

[BlkWRXWag]

Put a good 245 tire (not Michelin) on your new rims. Use your stock wheels when not racing.

[Jeremy1]

But if you only can do one set, I think the Pilot SS would be a good choice if DD more important to you than ax. Depends on your priorities. Also PSS are killer wets.

[alphaBETA]

For those who put the car on the rack, what was the stock alignment in the rear like?

Wondering if I need to plan to change it back there...if not I will just do the front at home.

[wiUFsh]

Originally Posted by BlkWRXWag

Put a good 245 tire (not Michelin) on your new rims. Use your stock wheels when not racing.

I wish I could use my stockers when not racing. They have winter tires on them so I will need to make a decision on which is the best size and tire to go with the Nurburgrings. I think the Michelin PSS would give me the best of both worlds.

I am not convinced thay a 245 would look great on an 8" wheel. Seems to to me it would look a little bulky.

[CopperTopNWOR]

STU is not unlimited wheel width for an AWD car. As to the worry about 245 on an 8" wheel I ran that for DS on my 2011 WRX and daily drive with a 245 on 8" wheel with my BRZ. It looks and functions perfectly fine.

[Harry]

Originally Posted by CopperTopNWOR

STU is not unlimited wheel width for an AWD car. As to the worry about 245 on an 8" wheel I ran that for DS on my 2011 WRX and daily drive with a 245 on 8" wheel with my BRZ. It looks and functions perfectly fine.

I think the OP meant rim width is unlimited in STU but for AWD cars, tire size is limited to 245, which sucks even more for newer, heavier STIs.

245 will look and work fine on 8" rim; on my 8.5" wide STI rims, the stock 245 sidewalls look vertical, no bulging.

- Harry

[CopperTopNWOR]

The OP was correct I had it goofy in my brain. Probably because you never really saw wider than a 9-9.5" wheel used since you were tire size limited for AWD vehicles.

[wiUFsh]

Originally Posted by Harry

I think the OP meant rim width is unlimited in STU but for AWD cars, tire size is limited to 245, which sucks even more for newer, heavier STIs.

245 will look and work fine on 8" rim; on my 8.5" wide STI rims, the stock 245 sidewalls look vertical, no bulging.

- Harry

I know 245 will work on an 8" wheel but my main reservation comes from the fact that my new wheels will sit perfectly flush with the fender and once the car is lowered I don't want it to rub. 10mm is 0.4" which is quite a bit when you're worried about tolerances.

For autox, I think the 235 will be good for now. Not reaching my max capability but good.

[mitchman]

Depends on the offset of your rims. If they are 45mm (or some large number) then you won't have issues with rubbing. And you can always run spacers if you want to get that "hella flush" look. lol!

But if your rims are something like 20mm, then you might have rubbing problems. Check out the wheel/tire thread for more info on what fits well.

[wiUFsh]

I'm getting 18x8 +35 TSW Nurburgrings in matte bronze... tomorrow actually. That's the only offset in 8" wide that will will fit a 2015 and stay within the STX category wheel width rule. 235s will look great, work just fine, and more importantly look nice and flush with the fender.

[mitchman]

Great! Sounds like a nice looking setup. :-)

Just realize that going with 35mm offset (stock is 55mm) will make your car 40mm wider (1.5 inches) which will make it a big tougher threading through the cones.

[wiUFsh]

Really? How's that? The wheels won't be sticking past the body.

[mitchman]

When you autocross and totally screw up, you hit cones with the front bumper. When you're just barely nicking the cones you're hitting them with your rear tires. Hard to explain.

Not saying you made a mistake, just sayin'. :-)

[Manicdan]

Originally Posted by mitchman

When you autocross and totally screw up, you hit cones with the front bumper. When you're just barely nicking the cones you're hitting them with your rear tires. Hard to explain.

Not saying you made a mistake, just sayin'. :-)

i'll try to explain!

the cone is the widest at the base, it sticks out about 2-3" more than the cone part of the cone (i'm so good at description, lol)

so unless you are driving with a front bumper so low that it could be used as a snow plow, then the only thing that would touch the base of the cone is the tires. when that happens the cone is stepped on more than pushed, but its being stepped on with lots of force moving quite fast. what i see happen all the time is the cone would wobble and fall over or be dragged just outside the box.

knowing all that the question becomes, how wide is too wide? and i cant answer that at all. nor have i ever googled if there is an obvious answer. (narrow cars do very well in autocross, so if i had to guess a wider car might do rather well on long sweeping courses, but any technical section would just slow them down too much)