Why are so many of you running 35 profile on 18"?

[uberschnell]

I noticed a lot of 1m drivers running 2XX/35R18 tires on 18" wheel set ups. Given the stock wheels are 19" and 35 profile shouldn't you run 40 (2XX/40R18)?

265/35/18 are 1" smaller in diameter then the 265/35/19 that come stock? 265/40R18 are the same diameter.

Stiffer sidewalls?

[balloonsalesman]

Originally Posted by uberschnell

I noticed a lot of 1m drivers running 2XX/35R18 tires on 18" wheel set ups. Given the stock wheels are 19" and 35 profile shouldn't you run 40 (2XX/40R18)?

265/35/18 are 1" smaller in diameter then the 265/35/19 that come stock? 265/40R18 are the same diameter.

Stiffer sidewalls?

+1

I'm still on stock set-up, but considering 18s. Curious as well.

[ayao]

OEM 18" tires on the E9x M3 platform are staggered 245/40/18 and 265/40/18. So your logic is correct.

However some of the track folk who have opted for a square 18" setup run 275/35/18 square to dial out some of the understeering tendencies of the stock setup.

[M3 Adjuster]

Originally Posted by ayao

OEM 18" tires on the E9x M3 platform are staggered 245/40/18 and 265/40/18. So your logic is correct.

However some of the track folk who have opted for a square 18" setup run 275/35/18 square to dial out some of the understeering tendencies of the stock setup.

275/35/18 is the most common track tire ...
And some of us even run Bridgestone 285/30/18 square

[redux]

Originally Posted by M3 Adjuster

275/35/18 is the most common track tire ...
And some of us even run Bridgestone 285/30/18 square

..... how can you drop the 285 square bomb without sharing the wheel specs to make it happen? I need widths and offsets, I've been on the fence about ordering some 18' forgelines with my VW tdi blood money.

[M3 Adjuster]

Originally Posted by redux

..... how can you drop the 285 square bomb without sharing the wheel specs to make it happen? I need widths and offsets, I've been on the fence about ordering some 18' forgelines with my VW tdi blood money.

LOL.

I am running the Apex Arc 8 in 18 x 10 ET 25.
I like them so much i have one pair for autocross and the other for track.


BF Goodrich R1 is my fave track tire in 285/30/18 all around. WAY more rubber to the road and the shoulder of the tire is much more square. They have a slightly lower sidewall height which actually allows them to fit in the vehicle a little better also.


The common size for most other tires is 275/35/18. I've run Goodyear takeoffs , continentals, maxxis RC-1 in that size and hankook RS3 in 265/35-18 for autocross.

The garage pic shows the 285/30 Bfg R1s in Tire Rack covers stacked next to the 275/35 Maxxis. Yeah it's that much more tire. !

Note - The third stack of tires was either 5
loose tires or 18s for my X1 with a loose tire on top.

You'll never realize exactly how much you are spinning the 275s at the rear under power until you go bigger. OMG What a difference.

If you want to go *beefy* in the rear, you can easily fit a 315/30/18 BF goodrich out back but you'll need a 10.5 inch rear wheel. I can't recall the ET I borrowed a friends. I posted photos in the past. Here is how they look from the side.

Totally badass look and hella grip at the rear but you aren't able to rotate. It definitely took a few autocross runs to get used to the car *not* rotating at the rear under power, I especially had to adjust my line entering a slalom. Not enough apparently as per the cone flying in my avatar.

One could potentially go as big as 335 on an 11" the rear but that's would be just insane.

PS. Forgelines are sweet !

[redux]

Perfect, it looks like the 285 RE-71r pretty much lines up size wise with the 285 R1's. I'll pass on the track focused tires because the 1m is just for the canyons and the occasional cone dodging. The balance of a square set up with the rear traction of a 285 sounds like a dream.

[M3 Adjuster]

Originally Posted by redux

Perfect, it looks like the 285 RE-71r pretty much lines up size wise with the 285 R1's. I'll pass on the track focused tires because the 1m is just for the canyons and the occasional cone dodging. The balance of a square set up with the rear traction of a 285 sounds like a dream.

I haven't run the RE-71r yet but I plan to put them on my autocross wheels In that size this year.

[redux]

Originally Posted by M3 Adjuster

I haven't run the RE-71r yet but I plan to put them on my autocross wheels In that size this year.

I just found an interesting option for forged wheels from bimmerworld. $500 a pop makes it the perfect price for abuse.

http://www.bimmerworld.com/Wheels-Ti...e-Wheel_3.html

[ayao]

http://www.m3post.com/forums/showthread.php?t=1224754

[CP 1///M]

With 18x9.5 +22 I run 265/35R18 Michelin PSS on stock liner which rubbed in front, and the drastic increase in front grip means it's prone to snap oversteer on crests. Right now, I kept my 265 PSS but put 12mm spacers in the rear, and run 5psi more in the fronts. In hindsight I should have gone +35 and adjust all 4 corners with spacers. Initially tried 25mm and milling down to 22mm still had rubbing in the rear.

The stock staggered setup had a mild understeer that works well, but the rear tires wear so much faster that I would want to ability to rotate to get more sessions out of the set. For the track I go to I would say I needed the wider track where as some might have gone to 285/30 and not adjust for the different offset in the rear

[chiraoka]

Originally Posted by M3 Adjuster

I haven't run the RE-71r yet but I plan to put them on my autocross wheels In that size this year.

Did you ever try the 285/30 R18 RE-71R square setup ?


CH

[M3 Adjuster]

Originally Posted by chiraoka

Did you ever try the 285/30 R18 RE-71R square setup ?


CH

No. I just had to cancel going to Road Atlanta. I have about two more events I want to make this year. And I'm likely good on tires for this year.

[chiraoka]

The M235R BMW factory race car uses:

BBS Motorsport R1C 18x10.0" ET24 light alloy wheels at all four corners with 265/660R-18 racing slicks.

http://www.rennreifenshop.de/compone....html?Itemid=0

[M3 Adjuster]

Originally Posted by chiraoka

Did you ever try the 285/30 R18 RE-71R square setup ?


CH

Quick update.... YES.. After reviewing with m3kerry who is running 275/35 Front and 285/30 rear to compete in SCCA events... he was able to confirm that 285/30/R18 RE-71R will fit up front.

I purchased a set this past week for my autocross wheels and took them out on track for a few sessions to heat cycle them in.

The 285/30/18s fit perfectly on my 18 x 10 wheels and I did not experience any rubbing while on track or in the paddock parking.

[CarJunkie]

Originally Posted by M3 Adjuster

Quick update.... YES.. After reviewing with m3kerry who is running 275/35 Front and 285/30 rear to compete in SCCA events... he was able to confirm that 285/30/R18 RE-71R will fit up front.

I purchased a set this past week for my autocross wheels and took them out on track for a few sessions to heat cycle them in.

The 285/30/18s fit perfectly on my 18 x 10 wheels and I did not experience any rubbing while on track or in the paddock parking.

Hmmm... my track wheels are 18x9.5. So you think they would hold the tires OK? My 275/35's look pretty wide on them.

[M3 Adjuster]

Originally Posted by CarJunkie

Hmmm... my track wheels are 18x9.5. So you think they would hold the tires OK? My 275/35's look pretty wide on them.

Check the manufacturer tire spec data to see what the recommended rim width is. Off the top of my head I am fairly confident 10-11 in is recommended but it can vary by tire and by manufacturer

Also while checking the tire data you can get an idea of how much wider they will be than the current tire. The tire specs should also give the tire width and typically they also provide a rim width Like shoe sizes , I wouldn't necessarily trust measurements across manufacturers but staying within a brand should be consistent. The 285/30s are beefy! Like a full 1" wider ...