Quote:
Originally Posted by jcfay
Thanks for the helpful thread. A couple points: folks, when posting tire sizes make sure you post wheel widths as well. It makes establishing if fitting a tire outside of standard spec will work. I'm a scientist, so I'm nitpicky (apologies in advance  )...
One question I'd like some input on is the true benefit from running a non-staggered tire setup like the OEM 20" winter setup with 285s front and back, versus a staggered winter setup. I've been told that the better winter wheels are always narrower, as you get a smaller contact patch with more pressure per surface area, and therefore you get better "bite" on snow and ice. I imagine this is true. But it's also sounding like JNoSol you've had great luck running a staggered setup, and on the DWS tires as well, which aren't pure winter tires (like the Pirelli Scorpions that come with the OEM 20 winter setup). So I'm guessing that it's not an issue, and that a staggered winter setup, and even one without a true full-bore winter tire is fine for the majority of us who aren't living in the great white north.
I guess I'm a little bummed I'm now going to be waiting for a 4k set of OEM 20s for winter through mid Jan at last estimate  when I could've gotten a nice custom set in quicker time...  |
Your hypothesis is correct. For maximum ice/snow grip, the narrower the tires the better. However, narrower tires means less grip on dry days and true winter tires have reduced speed limit.
I had 2 E70 X5s, now X5M with DWS with 275/40/20 front and 315/35/20 rear. I even had an F10 and F02 with DWS. They're solid. It snowed 14+ inches one year (within hours) in KC with a sheet of ice under the snow, my E70 with DWS gotten around very safely (felt very confident). I've driven my X5s with DWS on multiple snowboarding trips to the Vail/Copper, even took it offroad a few times. Never once do I feel that the car struggled or gotten stuck.
I like the staggered for the look and performance as well. It only snows 5 times per winter in KC, so rolling around in true winter tires would make my car less enjoyable on the nice days. (winter tires have speed limitation, not that I go faster than 110mph - wink)
On wheel width, as long as you're staying within the wheel width recommended by the tire manufacturer then you are fine. Slight variance isn't going to be detected by the ECU. The BMW ECU has a threshold around 1%. Any delta of more than 1% between front and rear, it will throw a code. The Porsche guys actually prefers to stretch their tires a little for better road feel. Their OEM would use 295s on 11" wide wheels (i.e. 991 Carrera 4S 19" setup), but BMW uses 315s on 11" wide wheels like on the non-M X5s . Porsche knows a thing or two about road feel. =)
Sorry about the wait on your set. If I were you, I would demand a partial refund or something for your wait. Just call BMW NA, keep complaining and escalate until you get something for your hassle.
