I attempted to ride yesterday. It was 19F according to the app when i left. I rode down a hill hitting 32mph THAT IS COLD but i felt good until i attempted to stop at a light at the top of the next hill. My rear disk brake locked/ froze up. I had to call my wife to come get me. I sorta got it lose but it was causing some serious drag. Rolled fine from the back of the van to the garage.. I took it to the shop and they did not see anything wrong. Rode this morning most of the ride was under freezing temps but new insoles kept feet toasty and it was a good ride.