Which is best for your e-bike?
If you’re thinking of buying your first e-bike – or perhaps your second or third – chances are you’ve come across some models that feature a belt drive instead of a traditional chain. But what difference does a belt drive really make, and is it really worth the usual premium over a tried and trusted chain?
We are here to help you.
What is a belt drive?
Until e-bikes became popular, almost every bike on the market used a chain. But the advent of e-bikes has increasingly made belt drives a popular alternative. The Gates Carbon Drive is by far the most popular of these, and it’s the one we’ll be focusing on the most. There are alternatives too, but Gates belts are so ubiquitous that unless otherwise stated, you can assume we’re talking about just this one brand. It’s not a sponsored post or anything, it’s just the nature of the market right now.
Anyway, to answer the question: at its most basic level, a belt drive is exactly what it sounds like. Instead of a chain transmitting power from your legs to the rear wheel, a belt does the job instead.
Duh, but what is the indicate to use a belt?
The most often cited advantage of a belt drive is durability. The Gates Carbon belt drive is reinforced with – you guessed it – carbon fiber. In case you haven’t heard, this stuff is pretty hard.
Gates carbon fiber belts were originally designed for high horsepower applications such as motorcycles and industrial machinery. E-bikes are relatively puny, so they should last pretty much forever. Gates says its CDX CenterTrack belt is rated for 10,000 miles under peak loads, while chains designed for e-bikes “fail at just 275 miles.” In the real world, its e-bike chains need replacing every 2,000 miles, while a Gates belt should last you up to 19,000 miles.
Of course, we’re taking Gates at his word here, but in my experience hearing about a belt drive failure is extremely rare. It does happen, but only under extreme conditions or usage (often situations where a chain would have given up much sooner). Meanwhile, e-bike chains are more prone to failure with mid drive motors due to the high torque applied to them compared to a regular bicycle.
Besides durability, belt drives are almost completely silent, provide an extra smooth feel when pedaling, require no lubrication, and won’t grease your pants. The only maintenance required is to keep the belt free of too much debris and the occasional strain, which is easy to do at home (and involves strumming the belt like a guitar).
Plus, they just look pretty cool, if you ask me.
What’s the catch?
There are two big caveats to using a belt drive.
Most notable is that the belts are incompatible with traditional derailleurs. This means that virtually all belt-driven bikes are either single-speed (which isn’t the biggest problem when you have a motor to help you) or use internal gears.
Usually, belt-driven e-bikes that are not single-speed use an internally geared rear hub. This means it’s rare to find belt-driven e-bikes that use rear hub motors. and have multiple gears, although you sometimes get bikes with gears closer to the pedals, like a pinion gear or Schlumpf drive. Yet these are the exception to the norm.
In other words, choosing between belt-driven and chain-driven e-bikes is often also a choice between internal and external gears. For some, some of the common pros and cons:
- Internally geared hubs are generally much more durable as the components are protected from the elements and physical damage.
- Derailleurs are generally lighter, although this is a marginal difference on most e-bikes.
- Internally geared hubs allow you to shift from a standstill, but some don’t allow you to shift while pedaling. Derailleurs can only change gears when the wheel is in motion, which can be troublesome if you’re stuck in a gear higher than a red light.
- Internally geared hubs are generally less efficient at converting your pedaling into motion than a well-maintained chain and derailleur, and vary more depending on what gear you’re in. Studies show that chains are around 97-99.5% efficient and tend to be pretty consistent across brands. Internally geared hubs can vary widely depending on the brand and even the specific gear you’re in; I’ve seen numbers ranging from over 99% to 80%.
- On the other hand, “well maintained” is an important caveat, as most people don’t bother to clean and lubricate their transmission on a regular basis. It should make up part of the difference.
- Derailleurs often offer more gears overall for better tuning of your pedaling cadence. But again, this is often not necessary on an e-bike.
Most belt drives also require an e-bike with a split frame, which means the frame has a cutout that allows you to remove the belt. That said, some companies make split belts, such as Firebut these are still quite rare.
It should also be noted that belt-driven e-bikes are normally more expensive. This is partly because of the belt itself, but also because most belt-driven e-bikes use mid-drive motors, unless they are single-speed designs. Naturally, you can’t use a rear hub motor with an internally geared hub, as they would have to take up the same amount of space.
The are some cheaper belt-drive e-bikes, like the Ride1Up V2 roadster (which uses a TopTrans belt). That said, the caveat to keep in mind with these alternative belts is that you might have a harder time finding a replacement if the belt fails.
So should I buy an e-bike with a belt drive instead of a chain?
Yes. If you have a choice between a belt-drive e-bike and a chain-driven e-bike, all things being equal, you should probably choose the belt-drive e-bike. There are very few negatives to the technology, and it’s just a more premium experience.
The problem is that everything else is not generally equal. As mentioned, belt-driven e-bikes can be more expensive, they are usually single-speed or use internal gears, and an internally-geared hub often adds quite a bit to a bike’s weight. So the better question might be “is a belt drive worth it?”
To that, I would say it ultimately comes down to price. In my experience, belt drives are primarily a really nice quality of life feature more than a must-have. In my daily use, my favorite thing about them is the quiet and smooth operation, not getting grease on my pants, and less maintenance overall.
While the durability is really nice for peace of mind, it’s not like I’m breaking any bike chains this often not either. It’s only happened to me once, and repairing a chain isn’t that hard to do with the right toolkit. And while I don’t care about all the possible weight savings and pedaling efficiency, I can understand that some people prefer those qualities in a more traditional setup.
In other words, getting a bike with an old chain and derailleur shouldn’t be a deal breaker if it otherwise checks all your boxes – unless you have unusual durability needs.
Yet belt-driven e-bikes are becoming more common every week and simply provide a more enjoyable riding experience. While a belt drive isn’t the only thing to consider when buying a new e-bike, it’s certainly nice to have.