Belts are used to run the blowers on 10,000
horsepower racing engines, the powertrains of 150 horsepower motorbikes, and more recently, the
drivetrains of many bicycles. I've been an avid user of belt drive trains on my bikes for about 12
years now, and have somehow clocked over 135,000 kilometers on these chain alternatives. I've taken
belt drivetrains up the world's highest roads, across dry deserts, through wild jungles, along
windy beaches, over monstrous salt flats, and into epic snowscapes. In this video, I'll tell you
why belt drive is better than chain drive for many cycling applications. I'll then explain why you
don't see belt drive on more bikes. And lastly, I'll comprehensively answer every question I've
ever received about these drivetrains. Throughout this video, keep in mind that I'm referring
to my experience with one specific product: Gates Carbon Drive CDX. But this is not a
sponsored video, and I have no affiliation with Gates. If I come across as enthusiastic,
it's simply because I'm a happy customer. Right, let's start with the
characteristics of bicycle belt drive. A bicycle belt is different from all other
types of belts. They are constructed from a polymer that is reinforced using multiple
carbon fiber cords. It's these tensile cords that make them especially strong. Rob Rast
from FLX bikes shows that you can even lift up the back of a van without breaking a bicycle
belt. These belts are usually paired with steel rear sprockets and alloy front sprockets,
and can be run single-speed or multi-speed when paired with a gearbox or internal gear hub.
So, why is belt drive better than chain drive? Firstly, belts are very long-lasting. Most
cyclists go years without needing to replace a belt or sprocket. I've recently put 35,000
kilometers into a belt drivetrain that saw many steep hills and every riding condition possible.
Others have even exceeded 40,000 kilometers. This is often three to four times further than
you can travel with a chain. Belts are also very low maintenance. This is because they don't
require any grease or lubrication, and much less cleaning too. Just a splash of water is often it.
Due to the lack of grease and oil, belts stay very clean. This means you'll never get black muck
on your hands or pants ever again. Belts also run eerily silent. Normally, all you can hear is
a light hum coming from your drivetrain. Belts are particularly good in adverse riding conditions.
This is due to the sprocket design, which can very effectively shed debris from its surfaces, unlike
a chain. But it's also because you'll likely be pairing your belt with a gearbox drivetrain, which
keeps your critical drive components sealed away and protected from the elements. Belts do not
rust. This is advantageous at the beach or in cold parts of the world where salt is put on the
roads. Ultimately, belts save you a lot of time. Most people don't like maintaining their bikes,
sourcing replacement parts, or going to bike shops for repairs. Belted bikes minimize all of these
things so you can spend more time learning about bikes on this YouTube channel! Okay, so if belts
are so good, why don't we see them on more bikes? The biggest downside is that belts are not
compatible with derailleur gears. This means you will need to use a gearbox or internal gear
hub for the gears. Now, I love gearboxes and think they're perfect for hard-working cargo, commuter,
and touring bikes. Gearboxes are strong, reliable, low maintenance, less susceptible to damage, and
you can even change gears while stationary. But gearboxes are often one kilogram heavier and five
percent less efficient than derailleur gears. They also don't shift that well under a load. So, if
you want the lightest or fastest bike - it won't be sporting a belt. Belts also require a special
frame. These frames must have a way to adjust the tension, they must have a split in the rear
triangle to install a one-piece belt, and they must have an especially stiff rear triangle so
that the belts cannot skip on the rear sprocket. Belts are often not found in bike shops. This
means that you will need to order replacements online. It's obviously best to do this before you
need them. Belt components have a higher upfront cost. A new CDX drivetrain is around US$250 or 250
euros, but keep in mind the cost per kilometer can be similar to a high performance chain drivetrain
due to the longer wear life. Belts cannot be repaired. This means that if you damage a belt,
it will need to be replaced. The good news is that broken belts are uncommon - I've only ever
broken one - but you should still carry a spare belt on long rides. They coil up small and weigh
under 100 grams, which is about the same weight as the chain breaker tool that you can now leave
at home. Okay, let's now move on to the questions, which will get more technical as we go. But
first, if you're interested in using belt drive for touring or bikepacking, check out my touring
and bikepacking bike buyers guides. You can learn everything about the bikes before comparing
over 80 belt drive bikes and 200 more with chain drivetrains. They're both updated yearly for
free and you can find the download links below. How do belts feel to ride? They feel like an
even smoother version of a well-lubricated chain. Despite the way they look, there is no noticeable
stretch in the belt thanks to the carbon fiber tensile cords that are hidden inside. Why don't
they use belt drive bikes in the Tour de France? To compete at the highest level of cycling, it's
necessary for riders to have the lightest and most efficient bikes. Unfortunately, belt drive bikes
are heavier and less efficient as a result of the gearbox, so you'll never see them in the Tour
de France. Don't automotive timing chains last longer than timing belts? This is often true, but
keep in mind that belts on bikes are a different application and technology. All durability tests
suggest that belts last longer on a bicycle. How expensive are belt drive bikes? A belt drive
bike with a three-speed internal gear hub starts at US$599 and a bit over 1,000 Euros get you a
bike with an 8-speed hub. The prices go well into five figures for fancy e-bikes. Can you use belt
drive with e-bikes? Most belts are approved for e-bike use, but in the gates range it's only the
CDC and CDX models that will allow for mid-drive motors. There's a torque limit to be aware of
too, the lower-cost CDC model is approved for 50Nm motors, while CDX is good for 90Nm. Can
you use belt drive in the mud and snow? I have taken my belt drive bikes through thousands of
kilometers of mud and snow. But keep in mind it's only Gates CDX that's rated for riding in the mud,
and the models that are rated to shed snow and ice are CDX, CDC and CDN. Can you use belt drive on
fixed gear bikes? You can and it looks pretty rad. Can you use belt drive with full suspension
bikes? Yes, a spring-loaded tensioner makes this possible. The tensioner is actually a super
cool bit of kit, as it accounts for increasing chainstay length as you get deeper into your
travel. For more, check out bikes by Zerode, Nicolai and Calvalerie. Do belts ever snap? They
do. The good news is that a broken belt is not a common occurrence, and it's usually preventable.
You can skip to this time where I discuss prevention in detail. Do vandals cut belts? This
has never happened to me and I have never heard of this happening to anyone else. How expensive are
belt drive components? A replacement drivetrain for my bike costs around US$250, which is a lot
but when you consider you can travel more than 35,000 kilometers for this price, it's not
any different from a high performance chain drivetrain. That said, chains can be run cheaper.
I'd estimate that Shimano Alfine components work out at half the price on a per kilometer basis.
You might be enticed by the entry-level Gate SideTrack drivetrain costing just one hundred
dollars, but it lasts less than half the distance of CDX, resulting in a similar cost per kilometer.
What does a belt drivetrain look like after 35,000 kilometers? The front and rear sprockets
are now less than one millimeter thick and are sharp to touch. This is approximately one-third
of the thickness of a new sprocket. But I've seen sprockets worn down much more than mine. Aren't
there limited gear ratios available on belt drive bikes? There are lots of gear ratio options
these days. You'll find eight front sprockets, 13 rear sprockets, and 23 belt blanks in the Gates
CDX range. Can you modify a frame for belt drive? You can, and I've actually added belt splitters
to multiple frames over the years. Some heavy duty frames will be well suited to modification, but
for the best user experience, I recommend using a frame that's engineered with the correct stiffness
to use a belt. If your modified frame turns out to be too flexy, the belts can lose too much tension
and will slip on the rear sprocket. You can combat this with a higher belt tension but this is less
efficient, and wears out your sprockets faster. What's the belt maintenance like? Belt
drivetrains are often said to be zero maintenance, but I didn't squeeze 35,000
kilometers out of my drivetrain without a little bit of care. Debris from the road
or trail wears the sprockets down quicker, so make sure to periodically use a toothbrush
and a splash of water to remove any grit. Do belts ever make noise? In dry environments
with ultra fine dust, you will likely end up with a squeaky belt. I use treadmill silicon
lubricant to keep things quiet. The good thing is that it's not an aerosol, so you can put it in
tiny bottles for short adventures. There is a new product from Universal Transmissions that dries
on as a film, I'll be testing that next. Please, avoid the Hanseline belt care stick,
as it's very sticky and attracts grit. How do you set the belt tension? Unlike
chains, belts do not get longer with use, so you won't need to adjust the tension until the
sprockets have worn down significantly. There are two typical ways to set the tension of a belt.
Some bikes use sliding rear dropouts, and others use adjustable eccentric bottom bracket shells.
You can use your smartphone to determine the appropriate tension by plucking the belt. Your
smartphone app will decipher the frequency and determine if your tension is correct. That said,
I've found that frames with especially stiff rear triangles will allow for significantly less belt
tension than is recommended by Gates. So, fit a snubber on your bike, which will keep the belt on
the rear sprocket, and tinker with your tension. How do you find the right belt length? Gates has
a calculator on their website that allows you to input both the chainstay length of your frame,
and the gear ratio you're looking to achieve. It will then spit out all of the sprocket sizes
and belt lengths that will work on your bike. Do belt drive bikes destroy hub and bottom bracket
bearings? It's possible that a belted bike with the maximum belt tension could prematurely wear
bearings. But on a properly engineered frame, the tension while riding will be similar to using
a chain. Are there any belt drive manufacturers other than Gates? Gates has the biggest market
share by a huge margin. They claim more than 1,000 bike models are fitted with their
drivetrains. You might have seen drivetrains from other manufacturers too, such as Veer, Advanced,
Accord, Driveline, or Continental - which is now a discontinued product. Veer is the most interesting
of the lot. They use a split belt design, which means the drivetrain can be retrofitted
to any bike with adjustable dropouts. I cannot comment on the performance or reliability, but the
Veer sprockets are currently available in just two different gear ratios, which significantly hinders
its use. Advanced claims to operate with less belt tension than other manufacturers thanks
to the deeper belt teeth, but there's almost zero information about them online. What's the
difference between the Gates Carbon Drive models? There are currently four different drivetrains:
SideTrack, CDN, CDC, and CDX. The best way to compare these products is to look at the table
in the Gates catalog. As the products get more expensive, the performance increases as a result
of more advanced materials. For example, inside the belts there are two different compounds for
the teeth, and three different materials for the carbon tensile cords. The sprockets are made using
different types of steel, as well as aluminum, and nylon composite. The CDX drivetrain offers the
most strength, durability and weather resistance, and can be used on the widest array of bikes.
There are now two different versions of CDX. Regular CDX is what you've seen me using on
my Koga World traveler for half a decade. This model uses stainless steel rear sprockets
and either stainless steel or aluminum front sprockets depending on the number of teeth. CDX
Black sprockets are brand new this year and are designed to be extra durable. These chromoly steel
sprockets should be better suited to torque-y mid-drive e-bikes, and with the new fin tooth
design, should shed debris better too. Are there any known Gates Carbon Drive problems? In 2015,
it was very easy to break the teeth on the first generation CDN plastic coated rear sprockets. As
a solution, Gates upgraded CDN users to stainless steel sprockets under warranty. And in 2016,
some Rohloff Hub belt sprockets developed a creak on the original splined carrier? This issue
was resolved in 2018 with a new carrier design. Why do some belts wear prematurely? The conditions
you cycle in are likely the biggest factor when it comes to component wear. Gritty conditions
wear out your sprockets much quicker than clean conditions, so make sure to clean your drivetrain
for the best mileage. High amounts of torque also wear sprockets faster, so expect less distance
from high torque mid-drive e-bikes. If you want, you can reduce the effective torque on your rear
sprocket by pedaling at a higher cadence, or by employing a higher drive ratio. The rear sprocket
size is important too, as smaller sprockets have fewer teeth engaged, and will therefore, wear
proportionately faster. I get great mileage from my 22 tooth sprockets. A high belt tension will
result in faster wear. This is one reason why you want a dedicated belt drive frame so that you can
employ a lower tension. Belt alignment is another key factor. You will wear your sprockets much
faster if your belt is not perfectly straight. Why do belts break? Belts can break from poor
alignment, insufficient tension, or internal cord damage. If the belt rides up onto the rear
sprocket, it can damage both the belt teeth and the internal tensile cords. This situation
occurs when there is insufficient tension, the rear sprocket is loose on your hub, or there's
poor alignment between the sprockets. A product called a Belt Snubber should ideally be fitted
to all belt drive bikes. These guide wheels make it impossible for your belt to lift onto the rear
sprocket teeth. Belts can also be damaged before they're even fitted to your bike. Twisting,
back-bending, or crimping belts can damage the carbon cords. Ryan Van Duzer made a video about
how his user error caused a belt to snap. He rolled his belt onto the rear sprocket, damaging
the internal cords. The lesson learned is that if your belt comes off, take your rear wheel out,
put your belt on the rear sprocket, and then refit your wheel. Are chains or belts more efficient?
Belt drive is just as efficient as chain drive, but can be more or less efficient depending
on the scenario. I'm going to get a bit nerdy, here but just know that the small differences
in drive efficiency across all these scenarios result in virtually no difference in your riding
speed. It's the gearbox or internal gear hub that's paired with belt drive that results
in the greatest efficiency losses - usually somewhere between two and six percent, or slower
riding speeds of 0.25 to 0.75km/h. But this is in perfect lab conditions. Expect the difference
to narrow when the riding conditions are muddy or gritty. With that preamble out of the way, some
have suggested that belt drive is less efficient than chain drive because when you spin the cranks
with your hands, you can feel some resistance. But this test doesn't tell the full story. According
to data collected from three different lab tests, belts do have an inferior drive efficiency at
low power outputs. This is because a belt is always under tension, whereas a chain can run
with some slack. As we introduce more pedal or electric power into a drivetrain, a belt
soon becomes just as efficient as a chain. The Trier University lab test suggests the
crossover point is at 120 watts power output, while the Friction Facts lab test suggests it's up
over 200 watts. And Universal Transmissions found the crossover to be at just 30 Watts. Either way,
most cyclists will hit these crossover points. Universal Transmissions (or UT) has recently
published some additional belts and chain data that's worth discussing. Please note that
UT developed the original belt drivetrain in partnership with Gates, and they are also the
distributor for Gates Carbon Drive in Europe. As a result, we should remain skeptical of the
chain efficiency, resistance, and wear rate data, as these numbers can vary significantly between
chain models and lubricants used. Alright, let's get on to the interesting findings. The
first is with regard to the drive efficiency on worn chains and belts. The data suggest
that worn belts run more efficiently than worn chains after both 5,000 kilometers
and 10,000 kilometers. In fact, the belt at 10,000 kilometers was running more efficiently
than the chain at 5,000 kilometers. This is simply because the chain gets longer over time and can no
longer mesh as well with the sprockets. How about if we use a new chain with the 5,000 kilometer
old sprockets? That's also less efficient than a belt after the same distance. But keep in
mind you'll go through multiple chains over the lifespan of one belt. This means the efficiency of
a belt drivetrain continually reduces over time, while the chain will jump between 96 and
98% efficient, depending on how worn it is. The other interesting test was regarding belt
drive efficiency at low, medium, and high tensions. This test shows that low tension is the
best at most power outputs, but by 50 Watts, all belt tensions are within one percent, suggesting
tension plays a minor role in cycling speed. If you've made it to the end here, you
deserve an honorary Ph.D. in belt drive. Congratulations! Many world bike travellers
have now demonstrated in the worst riding conditions possible that belt drive bikes are
long-lasting, strong, and low maintenance. If you prioritize durability and ease of use
over everything else, belt drive is the best drive option available. I recommend belts for
touring, commuting, bikepacking, cargo hauling, and recreational riding, in particular. However,
belts are not the best for every application. If you want the fastest and lightest bike, you will
still be best served by chains and derailleurs. To learn more about gearboxes, check out my
videos on affordable Shimano internal gear hubs, as well as Rohloff hubs, pinion gearboxes,
and Effigear gearboxes. There are also a bunch of new gearboxes coming in for 2023
- I'll link all of these videos down below.
I commute on a belt drive ebike, and I'd like to amend one thing in this video: He makes it sound like getting a replacement belt is really complicated. There's a calculator which requires precise measurements, and there's 23 different lengths times 4 different product lines. You actually don't need to worry about that unless you're building a bike.
If you need another belt, just look at the code written on your old belt, and get that. easy peasy.
I have a 2015 Novara Arkham, which used to be REIs brand before they swapped to Co-Op. it’s the best bike I’ve ever ridden in my life. It’s become my Daly commuter, the belt is so quiet oh man it’s like riding a cloud. In the nearly 10 years I’ve had it, the drive has had to be replaced though. Both times happened at the expense of REI, because it was their fault with the product some how. It seems to have to many parts that are made by companies that don’t quite stay in business, so when it’s time for a more intense tune up, the whole thing has to be replaced, because old parts can’t be fine. Ones that stabilizes out, I’ll be a loyal belt drive rider forever.
I've debated on getting a belt drive for my next computer but the added expense keeps me away.
Been better for a long time. But the frame has to be made for a belt drive. Not many are.
How do you think it will fair with mid-drive ebikes?
chain waxing is a good alternative if you're all about the durability but don't mind the added faff.
disagree
many minuses to belts