Joined: Dec 2004
Posts: 12,537
Likes: 791
From: Middle of da Mitten
Bikes: Trek 7500, RANS V-Rex, Optima Baron, Velokraft NoCom, M-5 Carbon Highracer, Catrike Speed
You can listen to your tires. A steady "whirrrrrr" indicates a smooth circle. A series of "whir, whir, whir, whir," would tell you you're applying power in pulses. Easier to tell with knobbies, but even road tires make a sound you can listen for.