[Porschefile]

Nah i'd say 255's would be fine. But I laugh every time I see 315's on the front of those vettes. Til they run that is...

[chaz58]

I would consider going down in aspect ratio to lower your center of gravity, and to give you better gearing. The MT cars are geared way, way to high.

I'm not a big fan of squeezing a large tire on a small rim. The rimwill slosh back and forth in all of the play the tire has. Look at good rim/tire combos designed by professionals. They generally use the largest rim (or smallest tire) possible, not the largest tire possible. You want to keep things tight, not sloppy.

Originally Posted by cwmizner

is going taller at one end but not the other going to mess up the DCT at all?

[cwmizner]

Originally Posted by chaz58

I would consider going down in aspect ratio to lower your center of gravity, and to give you better gearing. The MT cars are geared way, way to high.

I'm not a big fan of squeezing a large tire on a small rim. The rimwill slosh back and forth in all of the play the tire has. Look at good rim/tire combos designed by professionals. They generally use the largest rim (or smallest tire) possible, not the largest tire possible. You want to keep things tight, not sloppy.

oh really? what size would you suggest?

[eltoshan]

Originally Posted by chaz58

I would consider going down in aspect ratio to lower your center of gravity, and to give you better gearing. The MT cars are geared way, way to high.

I'm not a big fan of squeezing a large tire on a small rim. The rimwill slosh back and forth in all of the play the tire has. Look at good rim/tire combos designed by professionals. They generally use the largest rim (or smallest tire) possible, not the largest tire possible. You want to keep things tight, not sloppy.

That's true in any class that is not Stock. Since in SCCA Stock class you are limited by the OEM rim size, getting bigger tires is the only way to maintain acceptable contact patch in a corner other than a huge front sway bar and tire pressure.

[m3kerry]

For a daily driven and just running in D Stock car (street tire class), I jwould ust get stock size Dunlop Star Specs and run the car for 6 months to a year before putting any money into it. If you wanted to get competitve in the car, I would 1st figure out if the car can compete in the new D Stock and it can't. The 135i is already there and the last SCCA fasttrack has a item about bringing in the 335i from F Stock to D Stock.

So, I would not touch my daily. Just run it as is and have fun.

Side Note: Star Specs are the best tire in the SCCA ST classes and they are great in the rain.

[cwmizner]

that's fair enough, i already know i'm not winning nats in this car.

just want to be competitive locally in our street tire class.

the only choice here is a 255/35/18 or a stock size 225/40/18 for the front.

the 255 might be worth a tenth or 2, not sure if it's worth it, might look a look a little funny and more importantly might adversely affect the way the car behaves on the street

[chaz58]

245 all around on 8.5 rim width should be fine. You could do it with 8" rims too if you needed to, although the tire will have some slop in the rim. Keep in mind wider tires take longer to heat up.

I don't find 255s look funny on the front (with 8.5" rims). I doubt you could go any bigger. As far as handling, I get the feel the turn in is a little slower (compared to 225s) and on the street you loose a little bit of directional stability (minor), but no other drawbacks.

You do know that wider tires don't change the size of your contact patch, just the shape right?

m3kerry has some good advice above...

Originally Posted by cwmizner

oh really? what size would you suggest?

[vwong]

Originally Posted by chaz58

245 all around on 8.5 rim width should be fine. You could do it with 8" rims too if you needed to, although the tire will have some slop in the rim. Keep in mind wider tires take longer to heat up.

I don't find 255s look funny on the front (with 8.5" rims). I doubt you could go any bigger. As far as handling, I get the feel the turn in is a little slower (compared to 225s) and on the street you loose a little bit of directional stability (minor), but no other drawbacks.

You do know that wider tires don't change the size of your contact patch, just the shape right?

m3kerry has some good advice above...

In stock classes, you can't run wider wheels than what it came with the car from the factory. Not sure about the E46, but in the case of the E9x with 18" wheels, the front wheels must remain 8" wide. I'd love to run another pair of rear wheels (8.5" wide) on the front too, but it's not allowed in stock classes.

[cwmizner]

the amusing part (to me at least) was:

"I would consider going down in aspect ratio to lower your center of gravity, and to give you better gearing. The MT cars are geared way, way to high."

while this is true, i was asking him what size he suggested as I don't think there is a much shorter 18 out there than the 255/35/18, certainly not a street tire that will fit on a 8 inch rim.

[Porschefile]

Originally Posted by vwong

In stock classes, you can't run wider wheels than what it came with the car from the factory. Not sure about the E46, but in the case of the E9x with 18" wheels, the front wheels must remain 8" wide. I'd love to run another pair of rear wheels (8.5" wide) on the front too, but it's not allowed in stock classes.

True. It's crazy they let you run r compounds in stock sizes but you can't even run street tires on wheels .5" wider.

[chaz58]

You could easily do this on 17" wheels; you are right though not so easy on 18's.

Originally Posted by cwmizner

the amusing part (to me at least) was:

"I would consider going down in aspect ratio to lower your center of gravity, and to give you better gearing. The MT cars are geared way, way to high."

while this is true, i was asking him what size he suggested as I don't think there is a much shorter 18 out there than the 255/35/18, certainly not a street tire that will fit on a 8 inch rim.

[chaz58]

I think everyone here knows that. Hence, you could run 245's on 8" wide Front and 8.5" wide rear. Is that more clear?

Originally Posted by vwong

In stock classes, you can't run wider wheels than what it came with the car from the factory. Not sure about the E46, but in the case of the E9x with 18" wheels, the front wheels must remain 8" wide. I'd love to run another pair of rear wheels (8.5" wide) on the front too, but it's not allowed in stock classes.

[vwong]

Originally Posted by chaz58

I think everyone here knows that. Hence, you could run 245's on 8" wide Front and 8.5" wide rear. Is that more clear?

Originally Posted by chaz58

245 all around on 8.5 rim width should be fine. You could do it with 8" rims too if you needed to,

Yeah...the way you worded it earlier was not clear.

[cwmizner]

245 what? 245/40 is awful tall...

there is the kuhmo xs 245/35/18 though, i think that is the only option for a street tire in 245/35/18, i like the star specs better considering they'll be my daily driver tires

[cwmizner]

got the 255s all around on stock wheels, got 2nd place first time out in the car, 1st place is a known hot shoe normally not in the street tire class, so i got first in my mind...lol

dunlop star specs are nice improvement on the road, not a fan of the run flats at all

[vwong]

^^^ Congrats, dude! Is your street tire class indexed?

[cwmizner]

Originally Posted by vwong

^^^ Congrats, dude! Is your street tire class indexed?

thanks! yes, PAX indexed, 140 tread wear rating or higher

http://www.azsolo.com/

[cwmizner]

Been Autocrossing a fair amount, doing really well locally, still just the 255/35 Star Specs all around, zero other mods.

Went to the San Diego National Tour as they have street tire indexed class like I'm use to in Phoenix, got 5th of 18, enough for a trophy so that was cool, got the mod itch now.

thinking shocks, default is koni yellows, but not happy to learn you have take the rears off the car to adjust.

any other options for adjustable shocks that don't cost a huge amount (under 800 or so for set of 4) AND are worth the bother???


(I'll probably go with koni yellows and just go through the process of finding a good place to keep them adjustment wise)

[cwmizner]

Originally Posted by Chowbow

You should be fine with the 255s up front. Sure you don't want to run slicks though?

Definitely need a front sway bar on a stock height / stock class car. There's so little negative camber up front that the front swaybar actually HELPS with the understeer because it maintains the contact patch through corners. Are you going to do the dampers too? Vorshlag has AST shocks that are stock class legal, FYI.

those AST are probably too pricy for me, the couple options I saw come with springs and other stuff that I don't think you can use in stock??? maybe stock springs will work with them, but then you are buying stuff you can't use?

[Chowbow]

Originally Posted by cwmizner

those AST are probably too pricy for me, the couple options I saw come with springs and other stuff that I don't think you can use in stock??? maybe stock springs will work with them, but then you are buying stuff you can't use?

The ASTs are the only ones I know of that are off the shelf and work in stock classes. You need spring perches that are stock class legal and AST can provide those. I bet you Ground Control will have, or can make you a set as well. However they use the SA Konis typically and those require removing the rears to adjust the rebound.

[cwmizner]

so the 255s all around worked well, i went back to 225s in front and I regret it, going to pull them off and sell them.

thinking of going to 265 all around now (hankook RS-3s)

question, has anyone put a 265/35/18 on the stock 8 inch rim? aware it's wide tire for an 8 inch rim, i'm ok with that aspect.

my question is, will they rub?

a 5mm spacer is an option if it rubs on the inside, but don't want it to rub on the fender lip either...

the 255s never rubbed, so I never looked how close it was...