The best tyres should be placed in the rear of the car, whether your car is front-wheel or rear-wheel driven. With the "best" tyres we mean; those with the greatest tread depth, the ones with the biggest studs, or at least the ones that give the best traction. The abbrevation MS (also written as M+S / M.S / M-S / M&S, etc.) stands mostly for Mud and Snow, this basically means winter tyres. The minimal required tread depth for tyres in general is 1.6 mm, and 3 mm during winter conditions during 1 December - 31 March.