:iagree: :iagree: :iagree:
I ran summer performance tires on all my cars (and winter tires for winter season) and can confirm the above 100%.
Given the weight of the X5, even the 20'' shouldn't be problematic - as it was confirmed by the other posts.
Go for them - but of course even the best tires can't help when you don't drive safe and according to the given weather situations.

On the issue of wheel damage... I've had to have (17")wheels straightened twice in the last 18 mos on my 330xi thanks to Boston roads. I don't know how the 20s would stack up on the X5.

20" 214 = disaster waiting to happen.
Forget about BMW goodwill. 750+ to replace per rim.
My advice buy a q7 or consider non run flats and a set of "19'rims.

Agreed. also, wide tire and speed are the two biggest reasons for hydroplaning. Next would be tread depth. All-season are good all around tires but not great at anything. I run a summer and winter. Best of both worlds. But neither will work well if they are well worn.

M

Tire tread design is a big factor IMHO as well as age. The Goodyear F1 were exceptionally good in the wet. I had them on an '02 M5. I did an autocross at the BMW PC and was impressed with their dry handling. On the way home I encountered 90 miles of torrential rain. I was in the left lane running 50-55 mph the whole way home. Everyone else was running 40 or less or pulled over. I never once had any hydroplaning what so ever. I then did a track event with those tires and had a session in hard rain. They had incredible grip. I was taking corners 20mph faster than any Mustang or Vette. Only once did the DSC ever come on and that's because I took a corner wide and hit the slick gator at corner exit.

Everything else being equal, you'll get more better all-round performance in extreme conditions (heavy rain, mud, sand, snow) with a narrower, taller-profiled tyre (on a smaller wheel) than with a lower-profiled, wider tyre (on a bigger wheel). In ideal conditions (ie dry, smooth, sealed road) the opposite is more likely to be true.

It is a common misconception that all season tires are any better in rain than summer high performance. The all season is built to perform in all conditions including lower temps and some snow, but this makes it not great in any condition. In fact good summer tires will be at least as good if not better in rain water than all seasons!

Absolutely no issues so far in heavy rain. As for the winter, just get some good snow tires. Like you, I also thought that the 20's would be bad for the snow season. This is not the case. I've driven through snow and ice and have had no surprises. I live in a mountainous area of switzerland with very twisty roads. Couldn't be happier with the X5's performance.

Cheers,