I'm not sure. This last week it's been -18/-22 C, and it's been ok so long as I've good layering. My commute isn't that long though -- only about 6.5 miles. However, with all the snow we've had and ice, I can't go very fast, so the trip takes me 45/50 min instead of the 30/35. My bike is performing OK, although I'm not shifting much, basically set it to the desired gear as I leave the garage. Brakes are still working ok as far as I can tell.