I have been commuting on 700 X 25 and 700 X 28. When I initially started on the 25s I was apprehensive about them and I was riding tentatively on my new bike. I thought that I was going to pop them on every curb (we have nice granite curbs in Helsinki) and wipeout in every hard corner.

After some time though, I have become very comfortable on the 25s and find no real problems with them. Expect for one very large fine gravel hill that I tried to climb once and rear wheel just started spinning. It was a combination of low friction and me being in too low of gear which resulted in more torque then I required. After a brief stint on the 28s, I actually choose to go back to the 25s because I felt they let me move quicker on asphalt. Although the difference it quite small.

On a commuter I would probably go for 25mm or 28mm, and my max recommendation would be 32mm. You’ll just be wasting energy if you go for a larger tire on asphalt or hard packed trails. It just takes a little getting used to the thinner wheels.