I'm not sure that you can install snow-chains with 20' weels...

With my 18' weels I use TRAK 4x4 chains :

http://www.maggigroup.com/Files/06_Trak4x4_Data.htm

I think U can find it in the USA, very easy to install & remove, excellent efficiency, the best snow-chains I've ever had.

If you can't find them, try the RUD-comfort snow-chains wich are nearly the same by the conception, but I'm not sure that they have an agreement for 4WD :

http://www.autow.co.uk/snow_chains/r...t_centrax.html

Snow-chains should be installed to the front weels because of the steering and braking efficiency, but I install it on the back weels as it is written in the user manual p.140 because the car is still under waranty and it works perfectly.

;o) Stf.