02-18-2016, 10:11 AM | #23 |
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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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02-19-2016, 09:36 AM | #25 | |
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02-22-2016, 08:17 AM | #26 | |
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02-22-2016, 08:19 AM | #27 |
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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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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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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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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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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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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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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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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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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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