Snow Chains on my 20inch
 

I want to buy chains on my X5, 2002, 3.0i ... I am trying to buy a set of 4 snow tires that are 17 inch's, but I doubt I'll be able to find any in time for my snow trip this Friday.

I was at the store and found Z chains that fit my rear tire size of 315/35/20, but I wanted to wait and see if BMW recommends me using these cables, before I bought them.

I took out my Owner's Manuel, and it said the following:

They reference chains, but does this apply for cables as well? Can I place the Z cable on my 315/35 R 20 without it damaging my X5?

Depends on whether there is physically room.

Chains or cable chains on the rear wheels may get you moving if you are stuck, but they will do nothing to help you stop or turn.

If you don't have proper tires perhaps a rental vehicle would be safer.

:iagree:

Not sure I agree with that. Cables or chains are great for helping stop on ice and snow, especially with ABS - for the same reason as they work during acceleration. Cornering? Maybe not so much better due to the orientation of the cables/chains across the tire face. Still better than A/S tires bare.

Given the enormous wheel openings on the X53, I can't see why chains or cables would have any clearance problems.

Cables or chains on the rear wheels will not help you corner or stop. OK, they will help a little with stopping, for the 20% of the braking that the rears provide. But they will actually make cornering worse since they will increase under steer. The OP only asked about the rears, and BMW recommend not putting them on the fronts.

If you can fit them on four wheels (BMW is likely worried about clearance behind, not in front) then they could help. But it is still all a bad idea IMO.

Remember there is a max speed of generally 25mph with chains or cables.
I'd be worried about messing up the wheel with the chain rubbing on it. Then I'd be worried about the chain or cables breaking and damaging the vehicle.
Yes, they help you turn since you are only doing 15-25mph. But like JCL said, if you only have them on rear, your front tires still aren't really doing much.

What mountains are you going to? You mentioned Tahoe didn't you? Maybe you could call ahead to a tire store in Sacramento to get a set of wheels/tires ready and you could swing by the store and get them installed on your way?
Tirerack should be able to deliver you a set of mounted/balanced winter tires/wheels with rush shipping if you need them this weekend.
My preferred choice for local stores is Discount/America's Tire Company. They ONLY do wheels/tires, unlike other 'Tire' stores that do everything.

Last option...BMW dealers should be able to get you a set of wheels/tires by Friday, but you'll be paying twice what you would pay at Tirerack or Discount Tire.

Given the timing, I'd probably choose a rental car also.