I'm looking to get a new bike which will require the smallest amount of maintenance.

The bike will have an internally-geared hub and I have the choice of single speed chain or belt drive.

I have been looking at the Gates Carbon Drive and investigating maintenance costs:

A CDX belt is around 8 times more expensive than a chain where I live. Also the chainring and rear sprocket are round 4 times more expensive.

What is the lifespan of a Gates belt against a Single Speed chain? I've looked up online but peoples opinions are conflicting. Some say in similar conditions a belt will have a similar lifespan, while others claim up to 10 times longer use. What is the actual lifespan of a belt compared to a well maintained single speed chain in similar conditions?

I understand a belt drive is not maintenance free but much less than a chain. If a belt can last 4 times longer than chain then I would consider this worth the investment.

Also is there an expected life difference between 11 speed and single speed chains? As comparison to my current bike.

  • 1
    Welcome to the site, James! You might like to check out our short site tour for some information about how things work here but everything looks good so far. Mar 22, 2018 at 10:50
  • Note that different chains are reputed to have different life span in similar conditions. Certain people claim that a chain of brand "C" lived about three-four times longer than a chain made by vendor "K". Mar 22, 2018 at 18:13
  • Even if the belt system lasts 4x longer, but costs 8x as much then its still more expensive than chains.
    – Criggie
    Mar 22, 2018 at 19:09
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    If you go for the belt drive, please document your mileage and so on, and come back to this question with additional results. There's future searchers out there (like yourself) who would benefit from some accurate real-world numbers.
    – Criggie
    Mar 22, 2018 at 19:15

3 Answers 3


On single sped vs. 11 speed chains. A SS chain should last a lot longer than a derailleur chain. SS chains will have wider side-plates and therefore larger bearing surfaces. The big difference is that SS chains are run with the chain ring and sprocket aligned. Derailleur chains spend most of their time being run with the chain ring and sprocket offset so the chain has to cope with lateral forces.

  • Can I get a comment on the downvote? Do you disagree? Mar 22, 2018 at 14:02
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    Perhaps the downvoter didn't notice that the question does explicitly ask for comparisons between derailleur and single-speed chains. Mar 22, 2018 at 14:03
  • I have never heard of a chain using bearings, most use bushings, which wear and change the effective pitch of the chain (i.e., stretch). Also the side-plate width is different from the chain width. A wider chain will have wider bushings, which should wear slower. That said, this is not a guarantee as it also depends on the materials. Anecdotally, higher speed chains tend to use materials that wear better so there isn't much effective differences between chain widths, rather its the quality of the chain that seems to predict longevity.
    – Rider_X
    Mar 22, 2018 at 16:48
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    I said bearing surface not ball bearing. Bushings are a type of bearing. Mar 22, 2018 at 17:21
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    Perhaps the wording could be changed from "larger bearing surfaces" to larger wear surfaces in the rollers/bushings, or suchlike, which can therefore be more resistant to wear. Whilst I agree not all bearings have balls in them, the comment above does show how readers might misconstrue what is written.
    – Swifty
    Apr 23, 2020 at 7:52

I’ve run a gates CDX belt on a Specialized AWOL with a Shimano 11 spd internal hub for over 10,000 miles, much of that on wet or dusty trails. The front sprocket is aluminum and shows considerable wear, but the rear stainless sprocket and belt show very little visible wear.

I’m getting ready to replace the hub (bad 6th gear), so I’ll also replace the front sprocket and belt. Who knows, the belt may go another 10k, but I’ll let someone else do that test. Ease of maintenance sold me on the belt.

No one asked, but what about tension? Don’t run a belt too tight, it will wear out your BB bearings (I’ve done that test). Too tight it will squeak and too loose it will slip. Just barely tight is what I would describe.

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    Welcome to Stack Exchange. A couple things I like about your answer are how you conveyed your experience with a belt drive system, which was very specific to the question, and including a maintenance suggestion---kind of an "insider's tip." As a suggestion for improvement (and a heads-up), answers that include links to references that support said answers seem to draw more upvotes, and rightly so. Even if you could offer a torque value to your "just barely tight" practical experience, that would substantially improve the answer.
    – Jeff
    Feb 26, 2019 at 3:06
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    @Criggie AWOL is a bike line by Specialized. specialized.com/ca/en/awol/p/106553
    – Nayuki
    Jan 30 at 18:47
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    @Nayuki thanks - I've edited that tidbit into the answer. You can also edit other people's answers for similar clear improvements.
    – Criggie
    Jan 30 at 22:06

I have a CDX setup and IGH with a bit over 4000 km. It's on a mountain bike that I commute with and ride on really muddy trails.

I love the no maintenance aspect, I've only hosed it off a half dozen times, when it makes noise. I think that the road salt, sand, and mud are really hard on both cogs, I see most wear on the rear.

As far as tension, I put a 10 lb weight on the belt, midspan, then place a straight edge, from cog to cog, measure in between deflected belt, to straight edge. Gates says 10-12 mm, I find 15-18 mm causes less drivetrain noise and doesn't skip. I also use a belt snubber, placed close to but not touching the belt, as per Rohloff.

At 10-12 mm, I could feel the added drag. Not noticeable at 15-18mm. In my opinion, the dirty belt seems to spin much better than a muddy chain. I'm hoping to get 6000 km before replacing both cogs and belt at the same time, as a set. I don't think that you gain anything from changing just one piece, they wear as a set.

Last year, I covered 8000 km with 8 chains, 2 cogs, and 1 chain ring, my riding conditions are really tough on chains, and I would clean/oil every day. With that math, 1 belt equals 6-8 speed KMC chains, the good ones. All things considered, I'll take the belt drive, thanks. Maintaining a chain, in winter, and after every muddy singletrack ride sucks. Now I usually just grab my bike and go, it's perfect, for me.

Price is not much of a factor, when the positive aspects are considered.

  • 1
    Wow, and I thought I wear through chains quickly … :D
    – Michael
    Apr 23, 2020 at 7:51
  • I don't understand why you have to replace cogs and belt at same time. Do you find wear on the cogs? On my bike it looks like cogs are unaffected and I was told I probably never need to change them as the belt is softer. This is different to chains where it is metal on metal, so they are worn down equally. Apr 23, 2020 at 22:00
  • 1
    My gates belt had a complete failure at 8k miles. my Bike shop said that 8k miles is a lot for a belt.
    – toddcscar
    Mar 17, 2021 at 20:50

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