Cal Club Autocross Forums

Alright BMW fans and setup wizards. I got Simanyi saying don’t mess with the tire size, and Yom suggesting moving up to 265/285 on stock. I’m not ready to build a shed to house a new set of BBS and go to 18’s like Jacob. So for this next set of tires I’m thinking we should try the 265285 on the Bridgestones. No Yokes for 19s. That and the Dinan or hotchkis bar.

On the BMW forum people have put 285 305 without rubbing.

https://f87.bimmerpost.com/forums/showt ... 9810&page=

Is it worth having west coast optimize the alignment? No more camber available in b street though.

All input appreciated.

How wide are the wheels?

19x9 and 19x10

I’d probably go 245/265 but I’m not exactly a street tire squishing expert.

The Nationals winning FS e90 M3 was on a square 265 set-up.
I think I remember the fast 1M also ran a square set-up?

That seems like a pretty good place to start...

Go 265/285 BFG or Bridgestone as suggested. Rim width to tire size ratios IMO seems to be entirely on feel/feedback and the brand of tire. Moreso sensitive to ST classed cars. Too many variables.

The square setup is interesting. I like Jacobs rig square on 285 18x10.

Thanks Lugod. Too many variables is a good point.

Should I do the tires first and run a bit before getting the bar to see what just the rubber does?

What about Laura’s coaches - any thoughts to the order of changes? you know who you are - You all know full well that Laura’s pit crew is really bad at setup, and well, autox generally.

Matthew Corodimas wrote: ↑Thu Jan 16, 2020 10:13 pm Alright BMW fans and setup wizards. I got Simanyi saying don’t mess with the tire size, and Yom suggesting moving up to 265/285 on stock. I’m not ready to build a shed to house a new set of BBS and go to 18’s like Jacob. So for this next set of tires I’m thinking we should try the 265285 on the Bridgestones. No Yokes for 19s. That and the Dinan or hotchkis bar.

On the BMW forum people have put 285 305 without rubbing.

https://f87.bimmerpost.com/forums/showt ... 9810&page=

Is it worth having west coast optimize the alignment? No more camber available in b street though.

All input appreciated.

Front swaybar will always help keep the car stay consistent to a point (understeer does not = fast). I would do 265/285 to start out with and the sway bar. Keep note of the balance of the car after about 20 runs. If you feel it understeers and there is no softer front bar setting, you could try 265 square next go round of tires.

Jonathan Lugod wrote: ↑Mon Jan 20, 2020 11:29 am

Matthew Corodimas wrote: ↑Thu Jan 16, 2020 10:13 pm Alright BMW fans and setup wizards. I got Simanyi saying don’t mess with the tire size, and Yom suggesting moving up to 265/285 on stock. I’m not ready to build a shed to house a new set of BBS and go to 18’s like Jacob. So for this next set of tires I’m thinking we should try the 265285 on the Bridgestones. No Yokes for 19s. That and the Dinan or hotchkis bar.

On the BMW forum people have put 285 305 without rubbing.

https://f87.bimmerpost.com/forums/showt ... 9810&page=

Is it worth having west coast optimize the alignment? No more camber available in b street though.

All input appreciated.

Front swaybar will always help keep the car stay consistent to a point (understeer does not = fast). I would do 265/285 to start out with and the sway bar. Keep note of the balance of the car after about 20 runs. If you feel it understeers and there is no softer front bar setting, you could try 265 square next go round of tires.

The spring rates that come stock plus the suspension geometry on the car actually call for a ton of front bar. Only seems to get better the more you add, given stock springs/shocks. Took me a while to figure that out on my car before I swapped to the ohlins. Gives way more bite on turn in and better mid corner balance as well because the stock spring rates are way too soft and the extra platform is necessary to maintain any front grip. So adding front bar does not add understeer or have any negative effects because it's impossible to add too much bar given the overly soft springs and heavy car.

Bottom line is the bar change can potentially save as much as full second off a 60 second lap, but a tiny increase in tire width without the larger corresponding wheels for sidewall support may not net any time gain of appreciable difference. FWIW, i'm running 10.5" wide wheels square.

I chickened out a bit, and went with 255/275. Someone reported rub/bad fitment w/265 up front and didn’t want to make a mess.

I was not able to get the bar sorted yet, had to take off to India. Jacob - where is your shop? I’d like to try to get the bar sorted while I’m away. I won’t make next event, but Laura will be there. Let’s see what the interval is in l-pax with the new slightly bigger contact patch. Stayed with the Bridgestones.

Thanks again everyone. Second a lap would be a huge gain.

See you in March.

Wouldn't be surprised if the 265s on 19s rubbed pretty badly. Hopefully the 255s will be fine.

The shop is in Burbank. Werks 2 motorsport. Give them a call and mention my name.

I wish I had seen this sooner.

The 265/19 would have been a very slight rub, totally acceptable.

The rears go with 285/35/19 next time. The car needs the extra tire diameter for gearing.

And if you can go 18 in the front (it's legal,) 275/35r18 will fit with no rubbing
If I were to run the m2, that's what I would do.
275/35r18 from, 285/35r19 rear.