I have all seasons and they don`t seem to bad, still doesn`t have good stopping power though. winter tires would make it stop faster no doubt. there are some guys on here with winter tires and they say it drives just fine in the snow and stops just as good . what kind of tires do you have on your x5 brandon

I'm not sure of the exact model, but they are Yokohama all seasons, M and S rated. 235/60/18

Sounds like you may have a faulty vacuum pump or brake booster. Not unusual on BMWs. Before buying other tires I would determine if the brakes are working properly.

Doesn't matter if it is 4X4, has ABS or any other stopping or starting assists. If the tires are not effective on ice or snow, especially on a vehicle as heavy as an X5 it is not going to be fun. I suggest reading through the following thread and perhaps make a new post: http://www.xoutpost.com/bmw-sav-foru...endations.html

Everything functions properly, just serviced the entire brake system as well as replacing all the brake fluid. It's a beast on dry or wet (rain) roads. Also handles itself on dirt roads. It just has issues in the snow.

I just got home from running to the store. I found that if I really feather the brakes it's ok, plan far ahead for braking and drive like an old lady and it's ok. Still not what I'd expect out of an AWD SAV/SUV though. I may pick up some snow tires at the end of winter when people start selling them cheap for next year. For now I'll just deal with it.

You're certainly not alone, many people think AWD SUVs should be better in slippery conditions, but as for stopping, they will always be worse than the equivalent RWD or FWD vehicle. They are heavier (thus more inertia), usually have wider tires that float on top, and nothing about AWD makes them stop better.

My 535i (rwd) with Dunlop Wintersport M3s started and stopped better on snow and ice than either my X3 or X5 on all season tires.

another thread going right now:
http://www.xoutpost.com/bmw-sav-foru...tml#post968595

Don't blame the car for the tires' lackluster performance. Some all-seasons are better than others, and apparently your gf's Falkens are better than your Yoko's.
And like JCL says, you have a few things going against you. Your X5 is almost twice as heavy as her Sentra, which means twice the inertia you have to stop, even if you had the same tires, that alone would mean it should take quite a bit longer to stop (in low traction). Wider tires are the opposite of what you want for snow. Her Sentra probably has 195's? And your AWD means you have twice as many (+1 more) rotating masses adding rotational inertia also making it harder to stop.
Unlike JCL though, AWD should always be better at accelerating in snow. My horribly slow 325iX is a beast in the snow and must gain 50HP when its below freezing. My only complaint about the snow tires is that it requires alot more effort to do any good drifting in the snow now.
**misread JCL's post - yes, any car with snow tires will be better than any car without snow tires**
Tire rack has many good video reviews/comparison of snow tires vs all seasons. And pay attention to the comparison of studless vs studded. Studded tires are an unnecessary evil, unless you are ice racing.