20" Dueler H/P's in winter - will I survive?
 

I'm a newbie here and just picked up an 09 48i (err, see SN). I have 20's with Dueler HP's. I live on Long Island, NY and some of the winters can be cold, even though we had a mild one last year.
Is there any chance I can make it through a typical winter (4" of snow on ground but usually plowed within an hour, temps in the 30's) with these?

And anyone have an idea how many more MPG's I can get switching from the 20's to 18's? i'm getting about 10 city now, uggh.
Thanks.

The overall diameter of wheel + tire won't change when switching to 18's. With 18's, you will get tires with higher profile. Unless you go lower profile tires with 18's - but that would be ridiculous :)

Thanks for the info Seattle. I was wondering if the decrease in width of the tire would give me a few more MPG's and approx. how many?

You will NOT surive with summer-performance 20" Bridgestones or Dunlops - dont even bother, especially in LI... I once drove on them in 1" wintery mix/slush, and I felt like I had skis instead of tires (car was 4 mo old). The car was sliding sideways while waiting at an intersection on a slopy surface.

I do have 18" all-season bridgestones for winter driving, which also help dealing with potholes and cold temps/snow.

And since you are averaging about 10mpg now, I'd guess you are either heavy footed or have lots of stop-n-go....In either case, switching to 18" would not help mpg-wise :)

Due to less contact with surface, and therefore less friction, you will technically get better MPG. But I seriously doubt it will be anything noticeable.

You could also get the spare kit, ditch the RFTs, and put some all season Toyos on the 20s and run them year-round!

I'm going to look into all the suggestions. Much appreciated!
I'm pretty excited about being a first time BMW owner and am glad to be able to discuss/read about all things Bimmer here. Thanks again for having me.

Maybe I should've gone with the 3.0 model, but I fell in lust with the 4.8 Black Sapphire. It's covered by the CPO warranty until Fall of 2015.
Does anyone know if swapping rims/tires to a winter setup by myself will void the CPO warranty? Are the TPMs simple to reconnect? Thinking of all the above, as well as getting all-seasons on 18".

Btw, I just got the X5 last week and have been driving like a granny, locally. I hope hwy driving helps the mpg avg.

I'd check EBAY for some nice 18 takeoffs from someones e70 and get a set of Blizzaks or the like for winter setup. When I lived up north i always had a set of winter and summer wheels. find a set thats hub bore fits your year (can't recall if hub bore size has changed...."search" is not my friend!)...

TPMS modules changed during production years (I think 2010 - again I'm being lazy and not trying the search function here) so you'd just have to make sure the set in your second wheels was compatable. once they're mounted i think you just have to reset the sensors in I'drive...swapping between sets of 20's on mine i don't recall doing anything, they just worked.

You can swap rims yourself without voiding warranty. Just get the TPMS sensors..

Also, my dealer doesnt charge me to swap my rims out each season, maybe yours will be the same?

Fugetaboudit
 

I had the 18" Bridgestone RFT on my X5 here in MA. First winter ( tires had about 15K miles ) was scary on any snow. I put Vredestein Wintrac on the 18" rims and run 19" staggered Vredestein Ultrac the rest of the time.