well they will look flattened off in places if they are worn as they do have a tendency to slid and not roll like they are designed to,if the bike pulls away slowly sometimes and not others its a good indication that the rollers are jamming and not moving freely.if it pulls away slowly all the time then get some light weight rollers for it i would reccomend 5 gram or 4-4.5 gram with a race pipe fitted.
adam bike doctor
February 2010