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      02-18-2016, 10:11 AM   #23
Legal Bill
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The switch over worked fine. Tire Rack showed the Kosei fitting my 330i and it does. So I'm all set with winter tires for when the car arrives and after I try it out at the autocross and/or track, I have wheels that will work with a square set of 245 17s if I want to get a bit more serious.
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      02-19-2016, 09:34 AM   #24
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Quote:
Originally Posted by wjones14
Legal, I brought my M235i to the Palmer Motorsports track in MA this past August. Totally stock with the staggered Michelin PSS tires. It was fine for me in stock form. I was previously tracking the 2005 Mustang GT pictured in my avatar for the past decade, and the BMW was a revelation. Particularly because the Mustang was a daily driver with all season tires, and the Michelin PSS summer tires have sooooo much more grip. The torque of the 2 Series was also a revelation. The Mustang had almost equal torque - 320 versus 330 with the BMW - but the torque curve in the BMW is flat from 1400 rpm to over 4000, while the torque in the Mustang did not come on strong until almost 3000 rpm. So less need to downshift in the BMW and consequently I was always in 3rd or 4th gear at Palmer, even in the low speed 40 mph turns.

I even stuck with the stock tire pressures of 33 front and 38 rear and it was fine. The pressures increased with a few laps and the car was sticking. I didn't abuse it, but did manage a 2:03 lap and hit 126 mph on the front straight.

I would say to try the car out stock to see where you think it needs improvement based on your skill level.
I've done around two dozen track days in my 235i. After wearing out two or three sets of staggered MPSS tires, I went to a square setup on 17' Kosei's with 245-17 Hancook R-S3's. I've also started running tire pressures about 2 PSI higher in the front tires. This tends to counteract the oversteer nicely.
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      02-19-2016, 09:36 AM   #25
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Quote:
Originally Posted by Legal Bill
Well, I just bought a set of four Koesi K4R 17x8 wheels. They will serve as my winter snow tire wheel and then in the summer, I will use them for autocross and track day wheels. Even if I don't do much autocrossing or tracking, I'll get my use out of them in the winter.

I figure the first autocross I go to will be on the stock set-up. If I feel like I want to keep doing it, I'll buy a set of square tires for the Koseis.
Great choice. I did the same as you last year.
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      02-22-2016, 08:17 AM   #26
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Quote:
Originally Posted by rich8566 View Post
I've done around two dozen track days in my 235i. After wearing out two or three sets of staggered MPSS tires, I went to a square setup on 17' Kosei's with 245-17 Hancook R-S3's. I've also started running tire pressures about 2 PSI higher in the front tires. This tends to counteract the oversteer nicely.
Did you do anything about the camber?
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      02-22-2016, 08:19 AM   #27
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Originally Posted by rich8566 View Post
Great choice. I did the same as you last year.
Thanks. glad to see so many have already gone down this road. I have to say that on my 330i, the Koseis are way inside the wheel well. Hopefully they look better on the M235.
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      03-08-2016, 11:47 AM   #28
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If you plan to run in SCCA street class most of the modif mentionned in this post are not allowed. Also your wheels being 8 inches wide would not be legal either.

I did about 6 events last year in my m235 here in Canada (we following SCCA rules). My car is an automatic with a square setup running 235/40/18 handkook RS-3. I was most of the time running 34 front and 37 back in dsc off mode in manuel transmission mode.

The car is heavy and spring kind of soft so you need to adjust your driving to that. At the begining of the season I thought the car was pushing a lot even thinking of installing a bigger rear swaybar. After a few events at learning the car and adapting to it it was fine and I was able to win the club and provincial championships in street class.

I did find that the bigger/larger tires impacted the acceleration by a fair margin. This year I am planning to run a stickier tire and going to 17 inches to improve the gearing ratio and cut down on weight.

Hope this will help you and have a good season.
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      03-08-2016, 01:04 PM   #29
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Quote:
Originally Posted by gp_solo2 View Post
If you plan to run in SCCA street class most of the modif mentionned in this post are not allowed. Also your wheels being 8 inches wide would not be legal either.

I did about 6 events last year in my m235 here in Canada (we following SCCA rules). My car is an automatic with a square setup running 235/40/18 handkook RS-3. I was most of the time running 34 front and 37 back in dsc off mode in manuel transmission mode.

The car is heavy and spring kind of soft so you need to adjust your driving to that. At the begining of the season I thought the car was pushing a lot even thinking of installing a bigger rear swaybar. After a few events at learning the car and adapting to it it was fine and I was able to win the club and provincial championships in street class.

I did find that the bigger/larger tires impacted the acceleration by a fair margin. This year I am planning to run a stickier tire and going to 17 inches to improve the gearing ratio and cut down on weight.

Hope this will help you and have a good season.

Thanks. I used to run in SCCA and I know the rules for their stock class are very strict. I figure my first time or two will be with the stock set-up to see how I like it. If I think I am going to do it more often, then I'll decide what class I want to run in and what mods I want to buy. I needed new winter wheels for my car anyway, so I went with the Koseis in case I need them for autocross. If not, they will still be fine winter wheels.
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      03-09-2016, 01:56 PM   #30
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gp_solo2:

Your post brings up a question for you or anyone else wanting to chip in. What SCCA class do you run in with your square set up?

When I started autocrossing my M235i I was concerned that my PIO M-Performance LSD would toss me out of F-Street and queried the classification committee about running in Street Touring Ultimate (STU). The initial feedback was that contrary to the position in the past that options that did not actually come installed from the factory were not allowed in the (Stock)Street category, the LSD would be OK in F-Street. In the meantime I had gone to running a square 17-inch setup with 245/40 Dunlop DZ11 Star Specs and declaring my car in STU. Over the winter I got an email stating that the classification committee did not feel that the M235 should go into STU at this time, and subsequently the 2016 rule book lists the M235i in only F-Street and A Street Prepared.

I suspect that other are in somewhat the same situation. At my age, I'm not inclined to go far enough to make the car anything but grid filler in ASP. On the other hand, nowadays I autocross for my own enjoyment so it doesn't really matter if I would always be DFL locally in ASP.
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      03-09-2016, 06:24 PM   #31
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Thanks semclane for the heads-up. I too was intending to run STU this year, primarily to run a square tire setup and camber plates, ironically to limit my spending on (front) tires, and get rid of the understeer.

I ran a few locals last year in F-Street (I do have the LSD). My results were mediocre, and I thought if I could just get some camber, I'd be fine...

ASP is certainly a pickle. I have no divisional or national aspirations, but at the same time, I will still get beat by 5 to 7 seconds (on a 60 second course) within my region by evos and the like. OK, that is straight up to F-Street, but how much of that am I realistically going to get back?

So, do I spend money on relatively non-competitive parts to get a better driving experience, or do I kill two or three sets of front tires a year?
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      03-09-2016, 10:58 PM   #32
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Anyone ever try installing a wider tire on the stock front wheel? It may not be ideal, but the stock front wheels should be able to carry a wider tire.
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      03-09-2016, 11:56 PM   #33
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Quote:
Originally Posted by Legal Bill View Post
Anyone ever try installing a wider tire on the stock front wheel? It may not be ideal, but the stock front wheels should be able to carry a wider tire.
Tyre widths you can fit
to the rim width: 7.5"

Minimum
tyre width 205

Ideal
tyre width 215,
225

Maximum
tyre width 235
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      03-10-2016, 03:24 AM   #34
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Quote:
Originally Posted by rwalker View Post
Stock, the car pushes and eats front tires. Otherwise it's a blast.

Folks running the stock staggered setup run the front tire pressure a fair bit higher than the rears to counter understeer. I recommend coding for tire pressure and temperature in iDrive so you can watch them live.

The rest of this post covers recommended mods

An LSD helps a bunch to get power down out of corners and will help preserve your rear brake pads. I have a Quaife from HP Autowerks and it's great.

F8x LCAs and/or camber plates are pretty much a must or you will munch the outer shoulders of the fronts in very short order.

Finally, consider a square setup. I run a 255/35r18 square setup and it has served me well.

Let us know how you fare and where you end up with setup.
^ Rwalker is a great and knowledgeable driver at autocross.
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      03-10-2016, 11:47 PM   #35
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Semclane:

Are you saying that the SCCA commitee told you that an m-performance lsd is allowed in F-Street? If this is the case I am surprise and happy to hear that. Any evidence of this discussion you can share for my local club?

For the question regarding what class square setup would fall in I am running the original square setup that came from the factory front and rear 18x7.5 so they are definately falling under the F-Street class. This is why this summer I will try to go to 17x7.5 and try to run 245/40/17. This should all be legal in Street class and should give me more rubber for less weight and a lower overall gear ratio.

I am still slightly hesitating between 245,235 and 225 on a 7.5 rim. I know wider is usually better but there are different theorie on this and still searching a real test result that would confirm the best pick.
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      03-11-2016, 12:12 AM   #36
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Quote:
Originally Posted by gp_solo2 View Post
Semclane:

Are you saying that the SCCA commitee told you that an m-performance lsd is allowed in F-Street? If this is the case I am surprise and happy to hear that. Any evidence of this discussion you can share for my local club?

For the question regarding what class square setup would fall in I am running the original square setup that came from the factory front and rear 18x7.5 so they are definately falling under the F-Street class. This is why this summer I will try to go to 17x7.5 and try to run 245/40/17. This should all be legal in Street class and should give me more rubber for less weight and a lower overall gear ratio.

I am still slightly hesitating between 245,235 and 225 on a 7.5 rim. I know wider is usually better but there are different theorie on this and still searching a real test result that would confirm the best pick.
Don't think you should mount 245 on a 7.5 wheel.... 235 is already pushing it... your tire will flex like gelly and because you will have no camber it will roll over a lot...

I don't think the section width of the 245 will be much of an improvement over the 235 as the tire will just balloon

Last edited by pikcachu; 03-11-2016 at 12:20 AM..
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      03-11-2016, 12:30 AM   #37
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Pikcachu

I know it is streching a bit but I did ran about 10 year ago 225 wide on my 6 inches wide OE Miata wheel without any problem. Car was a lot lighter though.

Last year I ran 235/40/18 without issues. My only concern is that I lost on the acceleration side and I am pretty sure this is because of the taller sidewall increasing the overall gear ratio and the weight of the tire.

I know running 245 on a 7.5 inches wide wheel is not recommended and some bad thing may overide the benefits...this is why I am looking for real test data or comparaison. I want to get the max out of my F-Street setup. Dont know why BMW put 7.5 wheels on those car...would have been so much simple if they had put 8 inches wheels instead! ?
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      03-11-2016, 02:41 AM   #38
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Quote:
Originally Posted by gp_solo2 View Post
Pikcachu

I know it is streching a bit but I did ran about 10 year ago 225 wide on my 6 inches wide OE Miata wheel without any problem. Car was a lot lighter though.

Last year I ran 235/40/18 without issues. My only concern is that I lost on the acceleration side and I am pretty sure this is because of the taller sidewall increasing the overall gear ratio and the weight of the tire.

I know running 245 on a 7.5 inches wide wheel is not recommended and some bad thing may overide the benefits...this is why I am looking for real test data or comparaison. I want to get the max out of my F-Street setup. Dont know why BMW put 7.5 wheels on those car...would have been so much simple if they had put 8 inches wheels instead! ?
Oh I see, not sure what the weight difference would be from 225 to 235... can't think it would make much of a difference...

maybe it's the 10mm extra of diameter
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      03-11-2016, 06:26 AM   #39
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To be honest there is more variables than just weight and diameter since a saw the difference when switching back to my winter tires so different, width, tread design, conpound, diameter and weight and I agree that weight is not a major one here (but I know that going down to 17 inches will cut it and will be good for performance).

I will still do some additionnal research on internet but will likely try 245/40/17 RE71-R on 17x7.5 wheels this year. To me it looks like the most optimal setup for F-Street unless I find evidences that 225 would be better on 7.5 wide wheels.
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      03-11-2016, 12:25 PM   #40
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Quote:
Originally Posted by gp_solo2 View Post
Semclane:

Are you saying that the SCCA commitee told you that an m-performance lsd is allowed in F-Street? If this is the case I am surprise and happy to hear that. Any evidence of this discussion you can share for my local club?
It was in the SCCA June Fastrack last year.
Street
#16633 BMW M235i Clarification
The SAC has verified that the limited slip differential for the M235i is a port installed option and therefore eligible for use in competition in FS.
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      03-11-2016, 12:39 PM   #41
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Quote:
Originally Posted by semclane
Quote:
Originally Posted by gp_solo2 View Post
Semclane:

Are you saying that the SCCA commitee told you that an m-performance lsd is allowed in F-Street? If this is the case I am surprise and happy to hear that. Any evidence of this discussion you can share for my local club?
It was in the SCCA June Fastrack last year.
Street
#16633 BMW M235i Clarification
The SAC has verified that the limited slip differential for the M235i is a port installed option and therefore eligible for use in competition in FS.
Thanks a lot for this info...now I just got another reason to spend more $$$!
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      04-13-2016, 04:40 PM   #42
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My question is the same as Legal's

I've recently purchased a 2016 M235i (with the automatic), which I am starting to autocross. I'd like to stay in FS (at least for now) and keep the staggered tire set-up -- at least until I wear out some tires.

At this point, I'm not sure what tire pressures to run. The recommendations in this thread are all over the place, ranging from BMW's recommended pressures of 33/38 to as high as 55/50. I ran my car at 35/38 in an autocross last weekend, and did see scuffing on the top 1/2 inch of the front sidewall only. I'm sorry to flog what may be a dead horse, but does anyone have additional thoughts on tire pressure for the stock set-up that they're willing to share? Thanks.
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      04-13-2016, 08:00 PM   #43
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you should probably run high 30's low 40's in the front if you don't want to destroy the PSS shoulders...

better yet get some M4 LCA's and call it a day
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      04-13-2016, 10:19 PM   #44
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Quote:
Originally Posted by Bareiss View Post
I've recently purchased a 2016 M235i (with the automatic), which I am starting to autocross. I'd like to stay in FS (at least for now) and keep the staggered tire set-up -- at least until I wear out some tires.

At this point, I'm not sure what tire pressures to run. The recommendations in this thread are all over the place, ranging from BMW's recommended pressures of 33/38 to as high as 55/50. I ran my car at 35/38 in an autocross last weekend, and did see scuffing on the top 1/2 inch of the front sidewall only. I'm sorry to flog what may be a dead horse, but does anyone have additional thoughts on tire pressure for the stock set-up that they're willing to share? Thanks.
I recommend you code your car to show tire pressure and temps in iDrive and adapt from there, targeting ~40-42psi hot.

With stock camber you're going to be pushing into corners, heating up the fronts a lot, unless you're careful with entry speed.

My tires' grip starts to decrease at around 42psi hot... At autox, I get to "hot" by the 3rd run (less than 5 minutes between runs). I've been starting at 34psi cold, and my 3rd run (of 4) is usually fastest.

Last edited by rwalker; 04-13-2016 at 10:30 PM..
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