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      12-24-2012, 10:44 PM   #56
RPM90
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Drives: 335i Msport w/sport AT
Join Date: Mar 2006
Location: Chicago

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Quote:
Originally Posted by Sweeper View Post
Hi

I have direct connections in my BMW dealership , most knowledgable mechanic answered that the sidewalls are too soft. The modern F30 xdrive DSC feel the difference. And will cut out the power.

I've tried a lot of pressure configurations , nothing works.

I actually drive with DSC on till 65km/h , then I shut down the DSC or there are no way you could overcome the 80km/h barier , even on dry non snowy road.

And the actual feel of the drive is different A LOT between SUMMER RFT and WINTER non-RFT same diameter/high/wide. I've tried it on dry road and it's driving a toyota after bmw , expecially in the corners.

But BMW should warn the users about it.

It's now -14C , and 80cm of snow on most roads =] , if i didn't have xdrive I would sit home most of the time.


18 400m , staggered setup on non RFT pirellisottozerro
Yes, winter/snow tires can actually suck when they are not being driven on snow and/or very cold temps.
It's a major reason why I don't use them. The conditions I drive in the majority of winter around here, like 90%, is cold with dry or damp road surfaces. Actual "winter/snow" conditions are not that often and get cleaned up pretty quickly leaving cold, wet or slushy surfaces. AS tires handle those conditions very well.

Of course there will be huge differences in handling and ride comparing summer performance tires to winter/snow tires. Most snow tires are not designed to provide performance driving on snow conditions.
The newer winter sport tires are designed to give some performance back, but they also give up some of their snow ability. They are between a true snow tire and a very good AS tire.
Maybe you should try some of that type of winter tire. Along with AWD it should make for a better combination.

If DSC is sensing slipping tires are highway speeds, even when you apply very little throttle, I'd be worried and I would not use those tires in those conditions. If the tires are slipping while simply moving forward, then they're braking performance in those conditions can be dangerous.
But, this is only true if DSC is working properly and is actually detecting tire slippage.

What exactly about the sidewall does that tech think is causing the DSC to activate?
Softer sidewalls causing DSC to activate? Makes no sense, especially if it's activating once you get to highway speed. At highway speeds there is quite a bit less torque being applied to the drive wheels. It's not likely that the tires are actually slipping or losing grip while going forward.
If anything, in warmer temps snow tires will have even more bite/grip on the road surface.
As for cornering, handling will be mushy as the sidewalls are soft but so is the tread, which is going to squirm under lateral load.

This is very odd indeed.
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