275 hoosier a6/r6 on 18x9.5 42's

2657 Views 10 Replies 4 Participants Last post by T3h_Clap, Oct 21, 2013

spud majic

Discussion Starter · Oct 12, 2013

so as the titles says, im going to SM in autocross and some track duty and was looking for fitment details. i havent found anyone familiar with this setup yet so the basic run down is lowered about 1" and 2.75º front camber 2.5º rear. plan on rolling the rears. any work need done to the front? i could probably use a little more front camber though it would require modding the top hats a little.

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Subie_Pb

· #2 · Oct 12, 2013

Talk to a member called "teh_clap" on here. He will guide you in the right direction as he is the subaru guru for wheel fitment on here.

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oldlady

· #3 · Oct 16, 2013

will be fine at that alignment & height (suspension dependent of course), however i'd probably run more camber up front for the tire..

i ran 275/35 conti take offs (pretty much an R6) on a 9.5+35. fronts were untouched. front @ -3/ rear @ -2.5. ride height much lower than you are (in fact, too low TBH). rears were pulled a little bit. no rubbing front and rear. KW V3 w/ GT worx plates up front.

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T3h_Clap

· #4 · Oct 16, 2013

spud majic said:
so as the titles says, im going to SM in autocross and some track duty and was looking for fitment details. i havent found anyone familiar with this setup yet so the basic run down is lowered about 1" and 2.75º front camber 2.5º rear. plan on rolling the rears. any work need done to the front? i could probably use a little more front camber though it would require modding the top hats a little.

What suspension are you on?

If it's stock struts still you'll be fine, if you're on coils you'll need a spacer up front to clear the spring perches.

Also, which wheel are you looking at? there are a few 9.5 +42mm wheels that are known not to clear the brembos.

How competitive are you looking to be in SM?

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oldlady

· #5 · Oct 17, 2013

oh snap.. ahaaha note to self: just wait for clap.

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spud majic

Discussion Starter · #6 · Oct 18, 2013

coils im on are tein monoflex. 550/450. when i swap back to stock suspension for the winter ill machine out the top hats for around 3º or make new ones with a little added caster as well. im looking for decently competitive in sm. had someone who used to have a sm evo and was frequently taking overall pax in the region i run give me some feedback and he thinks i should do ok. he was on 285's and about 400whp on e85. im in the 300whp range but our courses typically doesnt have many long straights due to configuration limitations. currently running street tire index SM and usually place in the top 15 out of 75-100 avg total.

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T3h_Clap

· #7 · Oct 18, 2013

spud majic said:
coils im on are tein monoflex. 550/450. when i swap back to stock suspension for the winter ill machine out the top hats for around 3º or make new ones with a little added caster as well. im looking for decently competitive in sm. had someone who used to have a sm evo and was frequently taking overall pax in the region i run give me some feedback and he thinks i should do ok. he was on 285's and about 400whp on e85. im in the 300whp range but our courses typically doesnt have many long straights due to configuration limitations. currently running street tire index SM and usually place in the top 15 out of 75-100 avg total.

How long have you been autoxing? Any formal autox schools either locally or EVO schools?

Plans to go to nationals?

I made the mistake of going to R-Comps too soon in my AutoX career, spent the last 3 years unlearning bad habits.

The +42mm offset is going to be too high for those coils and 275s.

Are you open to different wheels? Willing to run spacers?

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spud majic

Discussion Starter · #8 · Oct 18, 2013

2 yrs autocrossing/tracking this car. about 10 yrs karting. not going to be running nationals, at least not in this car. eventually this will turn in to a full track car, but ill finish paying it off first and wait for all of my warranty to expire. main reason for the jump is i have forged pistons which kicks me out of stu and with the elimination of tire index the rest of the classes allow r-comp. and plus street tires fade pretty bad on track for 20 min plus sessions. the stock gr wheels are 8.5 +55 correct? based on my math that would put the inner edge of the wheel at basically the same distance from the struts. ive got at least 3/8" clearance now with the stock wheels. am i calculating something wrong?

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T3h_Clap

· #9 · Oct 18, 2013

spud majic said:
2 yrs autocrossing/tracking this car. about 10 yrs karting. not going to be running nationals, at least not in this car. eventually this will turn in to a full track car, but ill finish paying it off first and wait for all of my warranty to expire. main reason for the jump is i have forged pistons which kicks me out of stu and with the elimination of tire index the rest of the classes allow r-comp. and plus street tires fade pretty bad on track for 20 min plus sessions. the stock gr wheels are 8.5 +55 correct? based on my math that would put the inner edge of the wheel at basically the same distance from the struts. ive got at least 3/8" clearance now with the stock wheels. am i calculating something wrong?

Karting experience helps A LOT. With that much seat time you should be able to get a lot of the R-Comp potential right of the bat.

For your math.
The wheel yes, but you're going to a 275 tire and a hoosier at that.

If you're running 245 street tire going to a 275 R-Comp you'll be adding at least 15mm of tire inboard. You've only got about 9.5mm currently.

Even if you were on a 265/35/18 street tire now pinched on the 8.5 going to a 9.5 with a 275 will add more then the arbitrary 5mm inboard listed on the side of the tire.

Most people need a +38mm to +35mm to clear coilovers up front and still be under the front fenders with a 275/35/18.

What's your current tire size?

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spud majic

Discussion Starter · #10 · Oct 18, 2013

tires on it now are 245/40-18 z2's. i currently have a little over 9/16" gap between spring and tire/wheel both sides. is there really going to be that much more sidewall overhang? not that i am against running spacers but i would rather not if i dont have to.

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T3h_Clap

· #11 · Oct 21, 2013

spud majic said:
tires on it now are 245/40-18 z2's. i currently have a little over 9/16" gap between spring and tire/wheel both sides. is there really going to be that much more sidewall overhang? not that i am against running spacers but i would rather not if i dont have to.

Looking at the Hoosier #s they aren't 30mm wider then the Z2s, re-running the #s you'll actually gain a little bit of inboard clearance.

There is enough buffer that even if they are wider then what tire rack says you'll be ok.

I spoke too soon without looking at the tire rack measurements for the A6, sorry about that.

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