I just purchased a belt drive bike (Gates CD).

Maintenance free, according to the BS and what I have read online. The only attention is to replace it every 5000 km.

Since I usually ride around 8000 km/year, I was thinking to replace it once a year.

However I don't know what can happen by using a belt past its replacement swap mileage.

Can it snap like a belt in a internal combustion engine? Or, more in general, what are the risks?

  • Would there be any problem with a 6 month update other than the increased cost of belts ? I do wish Strava would have distance reminders for part replacements based on total mileage.
    – Criggie
    May 13, 2019 at 20:50
  • 1
    @Criggie, I am thinking of noting down my weekly mileage in a calc sheet. It won't be right to the meter, but it should be fairly accurate for me to notice the 5000 km threshold approaching.
    – L.Dutch
    May 14, 2019 at 6:23
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    @Criggie Strava actually has a warning system for mileage… but it's for running shoes only. I cannot see a similar setting for bikes or bike parts either. May 14, 2019 at 8:21
  • There are some apps that connect to Strava where one may track component wear meticulously. The app I use allowed me to set warnings based on distance, riding time, and overall time.
    – gschenk
    May 15, 2019 at 18:00

2 Answers 2


The mode of failure I have seen in similar belts used in industrial applications are typically one of two types. In the first scenario the belts show physical damage. The teeth may start to separate or be missing. You may also see cracks on either side of the belt. In the second scenario the belt just snaps. A visual exam will show no wear, cracks or damage. What you will see is the ends of the internal cordage be it Kevlar, Aramid or similar fibers. The second scenario is common enough that belt manufactures generally suggest time or mileage intervals rather than visual inspections. Depending on your model (some are easier to change than others) you could carry a spare belt. As others have commented the belt breaking has some consequences other than inconvenience. Any unexpected component failure can result in loss of control and potential injury.


It would typically snap in a 'high power' moment such as a start from a red light or in a climb where it could have you flying over the bar or hit the stem with a vulnerable bit of your anatomy. So I'd stick to the schedule and keep the family jewels safe! ;-)

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