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[Rassilon]

Hi,

I am considering getting a dual purpose square setup but I am wondering if it will negatively impacts DSC during daily drives when going through puddles or pouring rain?

Thanks.

[Pig Farmer]

I have no DSC issues running a 275/35/18 square setup, and have never heard of anyone having issues.

[Z K]

Power is only sent to the rear wheels on the M3... DSC only affects the drive wheels usually by cutting power or applying brakes to the rear.

[Rassilon]

I thought it compares wheel speed between front and rear wheels and the square setup will confuse it by having an incorrect ratio when there is no slip.

[shimmy23]

^ that sounds like an AWD setup

[Rassilon]

Originally Posted by shimmy23

^ that sounds like an AWD setup

Hmm you sure? I don't think the car knows the rear wheels are sliping just by looking at the rear wheel speed. It has to compare it with the front wheels as a reference to detect when rear wheels spin faster than the fronts.

[Richbot]

sensitive drivers will notice a square setup, or any setup that puts a smaller diameter than stock on the back than the car normally sees, will be a little more sensitive to wheelspin and cut in a bit earlier in some situations. In daily driving you'll never notice a difference IMO

it's looking at all 4 wheels plus the accelerometers, driver inputs etc. all the time, so changing one corner or one end of the car will change how it responds, in my experience

OTherwise the system doesn't care. Remember one of the factory snow tire setups for these cars is a square setup. It's not like some companies' default tuning *cough* *ahem*GM*cough*hack* excuse me! that can sometimes freak out if you get the stagger a bit wrong

[M3ANMACHINE]

No issues at all

[rymerc]

When I went to 275/35/18 square, dsc was even MORE annoying. Any enthusiastic weight transfer in roundabouts, or even brisk accel over rough pavement was so stunted I have to drive with DSC off all the time now. Maybe with euro-mdm or tuning the thresholds could be corrected, but it was super-nanny mode stock and on squared it's unliveable.

Just condition yourself to flip off DSC when you get in and start up. The M3 isn't the car for someone afraid of a little casual rotation, anyways.

[Richbot]

My "boring" toyota allows you to set cruise control with all the nannies off, wish that was possible on these

I have not noticed anything super-annoying from DSC except when I ran 285's up front and 275's in back in a failed attempt to kill my unkillable RS3's before I went back to a more streetable tire. Really cut in early with that setup. But then I almost always have my DSC off. Wore my DSC off button out, in fact, and had to replace it, which was the single most expensive unplanned failure on the car so far btw at $140. Nice that the car allows you to switch it off at any speed in any situation and it never comes back on until you turn the car off, not so nice that they failed to design for thousands of cycles, I probably use that button 6-7 times a day

[Z K]

Originally Posted by rymerc

When I went to 275/35/18 square, dsc was even MORE annoying. Any enthusiastic weight transfer in roundabouts, or even brisk accel over rough pavement was so stunted I have to drive with DSC off all the time now. Maybe with euro-mdm or tuning the thresholds could be corrected, but it was super-nanny mode stock and on squared it's unliveable.

Just condition yourself to flip off DSC when you get in and start up. The M3 isn't the car for someone afraid of a little casual rotation, anyways.

I ran a wrong sized 265/35R18 rear tire once. Like you, I did notice the DSC would cut power a lot sooner than when it actually lost traction.

As for running a different sized front, I very much doubt it makes a difference. DSC does not affect the front wheels.

On track, I always use DSC off so it makes no difference there.

[Richbot]

Originally Posted by Z K

I ran a wrong sized 265/35R18 rear tire once. Like you, I did notice the DSC would cut power a lot sooner than when it actually lost traction.

As for running a different sized front, I very much doubt it makes a difference. DSC does not affect the front wheels.

On track, I always use DSC off so it makes no difference there.

DSC does use front wheel speed to determine what to do. If you're running a wonky front tire size, you can get some weird results. The thing people call DSC cutting in is usually just the traction control doing its job to limit wheelspin, but DSC does much more than that when correcting under/oversteer like braking individual front wheels