The BMW 335i, as a high performance sport sedan, comes with original equipment tires sized 245/45/17, run flat "all season" tires. The optional sport package adds 18" high performance tires. Either set will have a lot of trouble in the snow, as when the snow packs the thin grooves in these tires, they provide little grip. As a rear-wheel drive car, the BMW 335i is inherently hard to handle in rainy or snowy conditions.

On the Other: Snow Chains are Another Option

If you don't want to invest in two expensive sets of tires for your 335i, BMW sells snow chains that can be fitted over your standard tires. As of early 2010, official BMW snow chains for the 335i run just a little more than $400. Make sure it is legal to use snow chains in the area in which you will be applying them.

Bottom Line

Snow chains are only recommended in heavy snow and are illegal in some areas for on-road use. Because the BMW 335i is a rear-wheel drive car fitted standard with tires not recommended for driving in winter-weather conditions, a good pair of snow tires are a must if you live in an area with frequent snows. Consider buying a second set of wheels, if you can afford it, to make switching from performance to snow tires easier.

Source:

BMW 335i official specs

Edmunds.com guide to tire safety

More Information:

BMW 335i official snow chains purchase site