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  • Handling question

    Ok first of all, i've searched, so Adam please bear that in mind. I could use some situation specific advice from the forum...

    At this point, i've been running 235 40 17s all the way around, on 17 x 8.5 wheels. The fronts rub at full lock, and i'm pretty tired (no pun) of announcing myself everytime i pull into a parking spot. I'm thinking its time to now go with 215 40 17s up front on the same rims. I'll have a 225 tire in the back still. My questions are:
    1) am i correct that this will fit better and
    2) what kind of handling difference am i going to notice? Are we talking serious push in turns or is this something that i will only be able to feel at 10/10ths?

    for tracking the car i have a set of 16inch Modas that i'm going to pop some sticky tires on, same size all around so that should keep it nuetral but what about my street setup?

    Thanks everyone and happy holidays!!
    "You must drive this car before you die, it really is that good." BMWCar Magazine re:the e30m3; Oct. 2002

  • #2
    I think you can be confident there will be no rubbing with the 215s. I used to run them all around and never had an issue.

    Handling differences are difficult to quantify. For a while long ago(in my "bling" days) I ran 215s in front and 235s in the rear. With that combo, it did "plow" a lot. I could start to feel the car wanting to push at around 8/10s. It was pretty noticeable.
    At that time I did not want to deal with making 235s fit in front, so I switched to 215s all around. Car handled much better that way.

    I do think 8.5" wide rims are a bit "much" for 215s. I imagine you can do it, but they will be pretty stretched. They were actually pretty stretched when I ran them on 8" rims.

    Another option, is doing what you need to do in order to run 235s in front. The secret IMHO is using the steering rack stops that TMS sells. After those were installed, I went from approximately 20 offset to 23. Moving the tire inward, once you have installed the steering stops, actually decreases rubbing because the tire swings in a smaller arc with steering input. You don't get the outer edge of the tire rubbing on the fender liners. I still have 5-10mm clearance between the tire and the strut, which is ample.

    The only downside is that the turning radius is reduced with the steering rack stops, but for me that is no issue at all.

    I have no rubbing at all now, except with a sharp bump like going up a curb or something when the wheels are at or near full lock. Happens very rarely, and I can live with it.

    HTH
    Last edited by Ironhead; 12-26-2008, 01:10 PM.

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    • #3
      Originally posted by Ironhead View Post
      I think you can be confident there will be no rubbing with the 215s. I used to run them all around and never had an issue.

      Handling differences are difficult to quantify. For a while long ago(in my "bling" days) I ran 215s in front and 235s in the rear. With that combo, it did "plow" a lot. I could start to feel the car wanting to push at around 8/10s. It was pretty noticeable.
      At that time I did not want to deal with making 235s fit in front, so I switched to 215s all around. Car handled much better that way.

      I do think 8.5" wide rims are a bit "much" for 215s. I imagine you can do it, but they will be pretty stretched. They were actually pretty stretched when I ran them on 8" rims.

      Another option, is doing what you need to do in order to run 235s in front. The secret IMHO is using the steering rack stops that TMS sells. After those were installed, I went from approximately 20 offset to 23. Moving the tire inward, once you have installed the steering stops, actually decreases rubbing because the tire swings in a smaller arc with steering input. You don't get the outer edge of the tire rubbing on the fender liners. I still have 5-10mm clearance between the tire and the strut, which is ample.

      The only downside is that the turning radius is reduced with the steering rack stops, but for me that is no issue at all.

      I have no rubbing at all now, except with a sharp bump like going up a curb or something when the wheels are at or near full lock. Happens very rarely, and I can live with it.

      HTH
      I run 235/40/17s on 17x 8.5s but the car is a track car so I don't care about rubbing... (rubbin's racing! :yup ...However, I have run a friend's staggered set of 17 x 8s with 215/40s on front and 235/40 on 17 x 9s in the rear. Indeed, the car plowed (read: MEGA understeer) on anything remotely close to 8/10ths driving on the street. You can try and manage it a bit with tire pressures, but you can't overcome physics... Pimpin ain't easy.... :click:

      I have never used the steering rack stops, but would recommend them in a heartbeat if you do more than profiling as you cruise around town.
      Last edited by M3 Adjuster; 12-26-2008, 08:03 PM.
      Mark Williams
      Dallas, TX

      Nothing says "welcome to the neighborhood" like a search... oh wait... looks like they are all gone! :rastajake:

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      • #4
        For what it's worth. I run 17x8 with 235/40/17 azenis all fours. All thats needed is a little mod of the plastic tray and liners. If you look the tray area can be slotted and moved forward, then tightened back down. The front panels housing the ducts/foglights can be mounted on the opposite side of the front tray. The liners can be trimmed or eliminated completely. No rubbing full lock to lock here. I mean lock to lock doing high speed doughnuts to check over dips.

        My opinion the 235s are just enough rubber. It's a little annoying that the M3 doesn't fit larger rubber in the front more easily. I couldn't imagine going back to 225 unless they are straight slicks. Ran on 16x7.5s with 225s before. True it was more nimble feeling but lacked grip on street tires. Felt like rollerskates. Acceleration for me is improved by upping rear gear to high locking 4.45. I'd imagine high modded 2.5s would want more rubber.

        Staggered works in some setups, but generally cause understeer "push". I'd adjust your plastic before downsizing to narrow rubber.
        Photos

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        • #5
          One other thing I noticed...

          Switching from 215/40-17 to 235/40-17, the car felt slightly more "sluggish" accelerating with the larger tires. This is probably both a function of heavier rubber and the slightly larger diameter. It was quite noticable, and the only thing I don't like about the 235s.

          I am about to change my final drive to 4.45, which should more than correct things....

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          • #6
            Leave it alone. I have the same size wheel set-up (for street use) and I just don't crank the wheel all the way. The car will push.

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            • #7
              I run 215/40/17 in my 17 by 8.5 with no rubbng issues at all, yes they are stretched but not in a massive way and the handling (once you get used to the different feel of the car) is good. No real understeer or oversteer, just the neutral balance that makes our cars so fun to drive.
              However compared to a stockk setup the car does seem to "feel like it pivots "more on the initial turn which ive put down to the wider stance on et13 BBS.

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              • #8
                :lostme:So where in LA traffic can you drive 8/10ths?:lostme:
                1988 Diamantschwarz



                "The original M3 is utterly brilliant in ways the people at M have either forgotten about or choose to ignore."

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                • #9
                  Originally posted by iainrobe30 View Post
                  I run 215/40/17 in my 17 by 8.5 with no rubbng issues at all, yes they are stretched but not in a massive way and the handling (once you get used to the different feel of the car) is good. No real understeer or oversteer, just the neutral balance that makes our cars so fun to drive.
                  However compared to a stockk setup the car does seem to "feel like it pivots "more on the initial turn which ive put down to the wider stance on et13 BBS.
                  Do you run the 215s all around? do you have any pix so i can see how much the stretch is?

                  And Criss, u can't drive 8/10ths in LA traffic, but all the canyons in malibu are fun places to put the car to work. Heading into a turn with nothing but cliff below is not a good place to find out that the car understeers lol.
                  "You must drive this car before you die, it really is that good." BMWCar Magazine re:the e30m3; Oct. 2002

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                  • #10
                    haha seriously. I took the M to LA last week at 9pm hoping there would be no traffic and I wound up on the 101 for 2 hours in traffic. Ouch!

                    - gabor

                    Originally posted by ///CRISS View Post
                    :lostme:So where in LA traffic can you drive 8/10ths?:lostme:
                    October 1987 build date.

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