Belts Are Now Higher Than Chains On Bicycles (135,000km of Testing)

Belts are used to run the blowers on 10,000 horsepower racing engines, the powertrains of 150 horsepower motorbikes, and extra not too long ago, the drivetrains of many bicycles.

I’ve been an avid consumer of belt drivetrains on my bikes for about 12 years now, and have in some way clocked over 135,000km (~88,000 miles) on these chain options.

I’ve taken belt drivetrains up the world’s highest roads, throughout dry deserts, by way of wild jungles, alongside windy seashores, over monstrous salt flats, and into epic snowscapes.

On this article, I’ll inform you why belt drive is best than chain drive for a lot of biking purposes. I’ll then clarify why you don’t see belt drive on extra bikes. And lastly, I’ll comprehensively reply each query I’ve ever acquired about these drivetrains.

All through this text, take note I’m referring to my expertise with one particular product – Gates Carbon Drive CDX. However this isn’t a sponsored article and I’ve no affiliation with Gates. If I come throughout as enthusiastic it’s just because I’m a cheerful buyer.

Let’s begin with the traits of bicycle belt drive.

What’s Bicycle Belt Drive?

A bicycle belt is completely different from all different varieties of belt. They’re constructed from a polymer that’s bolstered utilizing a number of carbon fibre cords.

It’s these tensile cords that make them particularly robust; Rob Rast from FLX bikes reveals which you could even raise up the again of a van with out breaking a bicycle belt.

These belts are normally paired with metal rear sprockets and alloy entrance sprockets, and might be run single-speed, or multi-speed when paired with a gearbox or inner gear hub.

Why Are Belt Drive Bikes Higher Than Chain Drive Bikes?

Rob English’s customized Undertaking Proper bikes usually are not constructed like regular. Picture: English Cycles

Firstly, belts are very long-lasting. Most cyclists go years while not having to switch a belt or sprocket. I’ve not too long ago put 35,000km (22,000mi) right into a belt drivetrain that noticed many steep hills and each using situation potential. Others have even exceeded 40,000km. That is typically three to 4 instances additional than you possibly can journey with a series.

Belts are additionally very low upkeep. It’s because they don’t require any grease or lubrication, and far much less cleansing too. Only a splash of water is commonly it.

As a result of lack of grease and oil, belts keep very clear. This implies you’ll by no means get black muck in your arms or pants ever once more.

Belts additionally run eerily silent. Usually, all you possibly can hear is a light-weight hum coming out of your drivetrain.

rohloff hub
Belt drive bicycles excel in muddy and gritty circumstances.

Belts are notably good in antagonistic circumstances. That is partly as a result of sprocket design, which might very successfully shed particles from its surfaces, in contrast to a series. But it surely’s additionally as a result of you’ll probably be pairing your belt with a gearbox drivetrain, which retains your important drive parts sealed away and protected against the weather.

Belts don’t rust. That is advantageous on the seashore or in chilly elements of the world the place salt is placed on the roads.

In the end, belts prevent loads of time. Most individuals don’t like sustaining their bikes, sourcing substitute elements, or going to bike outlets for repairs. Belted bikes minimise all of these items so you possibly can spend extra time studying about bikes on CyclingAbout!

If belts are so good, why don’t we see them on extra bikes?

Why Don’t We See Belt Drive On Extra Bikes?

Zerode was one of many first full-suspension producers to supply belt drivetrains. Picture: Zerode Bikes

The most important draw back is that belts are not appropriate with derailleur gears. This implies it is advisable use a gearbox or inner gear hub for the gears.

Now, I like gearboxes and assume they’re excellent for hard-working cargo, commuter, and touring bikes. Gearboxes are robust, dependable, low upkeep, much less prone to break, and you’ll even change gears whereas stationary.

However gearboxes are additionally typically one kilogram heavier, and 5% much less environment friendly than derailleur gears. In addition they don’t shift that effectively below load. So, in order for you the lightest or quickest bike, it gained’t be sporting a belt.

Belts additionally require a particular body. These frames should have a solution to regulate the strain, they should have a cut up within the rear triangle to put in a one-piece belt, and so they should have an particularly stiff rear triangle in order that the belt can’t skip on the rear sprocket.

Belts are sometimes not present in bike outlets. This implies that you will want to order replacements on-line – it’s clearly greatest to do that earlier than you want them.

Tout Terrain bikes have been utilizing belt drivetrains for over a decade now. Picture: Tout Terrain

Belt parts have a increased upfront value. A brand new CDX drivetrain is round US $250 or €250. However take note the cost-per-kilometre might be much like a high-performance chain drivetrain as a result of longer put on life.

Belts can’t be repaired. Because of this if you happen to injury your belt – it can should be changed. The excellent news is that damaged belts are unusual (I’ve solely ever damaged one) however you must nonetheless carry a spare on lengthy rides. They coil up small and weigh below 100 grams, which is about the identical weight because the chain breaker device which you could now depart at residence.

Let’s now transfer on to the questions, which is able to get extra technical as we go.

Normal FAQ

Urwahn bikes mix Shimano Alfine hubs with Gates Carbon Drive. Picture: Urwahn Bikes
How do belts really feel to experience?

They really feel like a fair smoother model of a well-lubricated chain. Regardless of the best way they give the impression of being, there is no such thing as a noticeable ‘stretch’ within the belt due to the carbon fibre tensile cords which can be hidden inside.

Why don’t they use belt drive bikes within the Tour de France?

To compete on the highest stage of biking, it’s mandatory for riders to have the lightest and best bikes. Sadly, belt drive bikes are heavier and fewer environment friendly (on account of the gearbox), so that you’ll by no means see them within the Tour de France.

Don’t automotive timing chains last more than timing belts?

That is typically true. However remember the fact that belts on bikes are a distinct utility and know-how. All sturdiness assessments counsel that belts last more on a bicycle.

How costly are belt drive bikes?

A belt drive bike with a 3-speed inner gear hub begins at US $599 (Precedence Basic Plus). And a bit over €1,000 will get you a motorbike with an 8-speed hub (Dice Hyde). The costs go effectively into 5 figures for fancy e-bikes.

Can you utilize belt drive with eBikes?

Most belts are permitted for eBike use. However within the Gates vary, it’s solely the CDC and CDX fashions that may enable for mid-drive motors. There’s a torque restrict to concentrate on – the lower-cost CDC mannequin is permitted for 50Nm motors whereas CDX is nice for 90Nm.

Can you utilize belt drive within the mud and snow?

I’ve taken my belt drive bikes by way of 1000’s of kilometres of mud and snow. However take note it’s solely Gates CDX that’s rated for using within the mud. The fashions which can be rated to shed snow and ice are CDX, CDC, and CDN.

You possibly can take the Gates Carbon Drive CDX drivetrain by way of some depressing circumstances! Picture: Ryan Van Duzer
Can you utilize belt drive on fastened gear bikes?

You possibly can, and it appears fairly rad. Mounted gear belted bikes might be discovered over at Schindelhauer and Precedence.

Can you utilize belt drive with full suspension bikes?

Sure, a spring-loaded tensioner makes this potential. The tensioner is definitely an excellent cool little bit of package because it accounts for the rising chainstay size as you get deeper into your journey.

For extra, try bikes by Zerode, Nicolai, Gamux, Riese & Muller, Aska, and Cavalerie.

Do belts ever snap?

They do. The excellent news is {that a} damaged belt is just not a typical incidence and it’s normally preventable (I’ll reply this in additional element within the part “Why do belts break?”).

Schindelhauer bikes are 100% belt pushed! Picture: Schindelhauer Bikes
Do vandals minimize belts?

This has by no means occurred to me, and I’ve by no means heard of this taking place to anybody else.

How costly are belt drive parts?

A substitute drivetrain for my bike prices round US $250, which is lots, however when you think about which you could journey greater than 35,000km for this worth – it’s not any completely different from a high-performance chain drivetrain.

That stated, chains might be run cheaper. I’d estimate that Shimano Alfine parts work out at half the value on a per-kilometre foundation.

You is perhaps enticed by the entry-level Gates SideTrack drivetrain costing simply US $100, however it lasts lower than half the gap of CDX, leading to an analogous value per kilometre.

Aren’t there restricted gear ratios out there on belt drive bikes?

There are many gear ratio choices as of late. You’ll discover eight entrance sprockets, 13 rear sprockets, and 23 belt lengths within the Gates CDX vary.

Are you able to modify a body for belt drive?

You possibly can, and I’ve truly added belt splitters to a number of frames through the years. Some heavy-duty frames might be well-suited to modification, however for the perfect consumer expertise, I like to recommend utilizing a body that’s engineered with the proper stiffness to make use of a belt.

In case your modified body seems to be too flexy, the belt can lose an excessive amount of stress, and can slip on the rear sprocket. You possibly can fight this with a better belt stress, however that is much less environment friendly and wears out your sprockets sooner.

Upkeep FAQ

What’s the belt upkeep like?

Belt drivetrains are sometimes stated to be zero upkeep however I didn’t squeeze 35,000km (22,000mi) out of my drivetrain with no little little bit of care.

Particles from the highway or path wears the sprockets down faster, so make sure that to periodically use a toothbrush and a splash of water to take away any grit.

What does a belt drivetrain appear to be after 35,000km?

The entrance and rear sprockets at the moment are lower than 1mm (1/32″) thick and are sharp to the touch. That is roughly 1/3 the thickness of a brand new sprocket, however I’ve seen sprockets worn down rather more than mine.

My new entrance sprocket in comparison with a worn-out one.
Do belts ever make noise?

In dry environments with ultra-fine mud, you’ll probably find yourself with a squeaky belt. I exploit treadmill silicone lubricant to maintain issues quiet. The great factor is that this isn’t an aerosol, so you possibly can put it in tiny bottles for brief adventures.

There’s a new product from Common Transmissions that dries on as a movie – I’ll be testing that subsequent. Please keep away from the Hanseline belt care stick because it’s very sticky and attracts grit.

How do you set the belt stress?

In contrast to chains, belts don’t get longer with use, so that you gained’t want to regulate the strain till the sprockets have worn down considerably.

There are two typical methods to set the strain of a belt. Some bikes use sliding rear dropouts, and others use adjustable eccentric backside bracket shells (see image beneath).

KOGA WorldTraveller Touring Bike
Some frames, such because the KOGA WorldTraveller, use an eccentric backside bracket to regulate the belt stress.

You should utilize your smartphone to find out the suitable stress. By plucking the belt, your smartphone app will decipher the frequency and decide in case your stress is right.

That stated, I’ve discovered that frames with particularly stiff rear triangles will enable for considerably much less belt stress than is advisable by Gates. Be sure to’ve acquired a ‘belt snubber’ in your bike (which retains the belt on the rear sprocket), and tinker along with your stress.

How do you discover the suitable belt size?

Gates has a calculator on their web site that means that you can enter each the chainstay size of your body and the gear ratio you’re trying to obtain. It is going to then spit out the entire sprocket sizes and belt lengths that may work in your bike.

Do belt drive bikes destroy hub and backside bracket bearings?

It’s potential {that a} belted bike with the utmost belt stress might prematurely put on bearings. However on a correctly engineered body, the strain whereas using might be much like utilizing a series.

Gates Carbon Drive Parts

Are there any belt drive producers apart from Gates?

Gates has the largest market share by an enormous margin; they declare greater than 1000 bike fashions are fitted with their drivetrains.

You might need seen drivetrains from different producers too, reminiscent of Veer, Superior, Accord, Driveline, or Continental (which is now a discontinued product).

The Veer belts are capable of be separated, which lets you match them right into a body with no belt splitter.

Veer is essentially the most fascinating of the lot. They use a split-belt design which suggests the drivetrain might be retrofitted to any bike with adjustable dropouts. I can’t touch upon the efficiency or reliability, however the Veer sprockets are presently out there in simply two completely different gear ratios, which considerably hinders its use.

Superior claims to function with much less belt stress than different producers due to the deeper belt tooth, however there’s virtually zero details about them on-line.

What are the merchandise within the Gates Carbon Drive vary?

There are presently 4 completely different drivetrains: Sidetrack, CDN, CDC, and CDX. The easiest way to check these merchandise is to take a look at the desk within the Gates catalog.

Because the merchandise get costlier, the efficiency will increase on account of extra superior supplies. For instance, contained in the belts, there are two completely different compounds for the tooth and three completely different supplies for the carbon tensile cords. The sprockets are made utilizing several types of metal, in addition to aluminium, and nylon composite.

The CDX drivetrain provides essentially the most energy, sturdiness, and climate resistance, and can be utilized on the widest array of bikes.

There at the moment are two completely different variations:

Common CDX is what you’ve seen me utilizing on my KOGA WorldTraveller for half a decade. This mannequin makes use of stainless-steel rear sprockets, and both stainless-steel or aluminium entrance sprockets, relying on the variety of tooth.

CDX:Black sprockets are model new this yr and are designed to be additional sturdy. These Chromoly metal sprockets must be higher suited to torquey mid-drive electrical bikes, and with the brand new fin tooth design – ought to shed particles higher too.

Are there any recognized Gates Carbon Drive issues?

In 2015, it was very straightforward to interrupt the tooth on the first-generation Gates CDN plastic-coated rear sprockets. As an answer, Gates upgraded CDN customers to stainless-steel sprockets below guarantee.

And in 2016, some Rohloff hub belt sprockets developed a creak on the unique splined service (half #8540). This situation was resolved in 2018 with a brand new service design (half #8540L).

Older Gates CDN sprockets have been recognized to interrupt in 2015-16. Customers acquired CDX sprockets as a repair.


Why do some belts put on prematurely?

The circumstances you cycle in are probably the largest issue with regards to element put on. Gritty circumstances put on out your sprockets a lot faster than clear circumstances, so make sure that to wash your drivetrain for the perfect mileage.

Excessive quantities of torque additionally put on sprockets sooner, so anticipate much less distance from high-torque mid-drive e-bikes. In order for you, you possibly can cut back the impact of torque on a rear sprocket by pedalling at a better cadence, or by using a better drive ratio.

The rear sprocket measurement is vital too as smaller sprockets have fewer tooth engaged and can, due to this fact, put on proportionally sooner. I get nice mileage from my 22-tooth sprockets.

A excessive belt stress will end in sooner put on. That is one motive why you desire a devoted belt drive body – you possibly can make use of a decrease stress.

Belt alignment is one other key issue. You’ll put on your sprockets a lot sooner in case your belt is just not completely straight.

Why do belts break?

Belts can break from poor alignment, inadequate stress, or inner twine injury.

If the belt rides up onto the rear sprocket, it might injury each the belt tooth and the inner carbon tensile cords. This case happens when there’s inadequate stress, the rear sprocket is unfastened in your hub, or there’s poor alignment between sprockets.

A product known as a ‘belt snubber’ ought to ideally be fitted to all belt drive bikes. These information wheels make it unimaginable to your belt to raise up onto the rear sprocket tooth.

Belts will also be broken earlier than they’re even fitted to your bike – twisting, back-bending, or crimping belts can injury the carbon cords.

Ryan Van Duzer made a video about how his consumer error triggered a belt to snap. He ‘rolled’ his belt onto the rear sprocket, damaging the inner cords. The lesson discovered is that in case your belt comes off, take your wheel out, put the belt on the sprocket, after which refit your wheel.

Are chains or belts extra environment friendly?

Belt drive is simply as environment friendly as chain drive, however might be roughly environment friendly relying on the state of affairs.

I’m going to get a bit nerdy right here, however simply know that the small variations in drive effectivity throughout all these situations end in nearly no distinction in your using pace.

The FahrradZukunft drive effectivity lab assessments give us an thought of how a lot vitality we lose from bicycle gearboxes. Graph:

It’s the gearbox or inner gear hub that’s paired with the belt drive that ends in the best effectivity losses, normally someplace between 2 and 6%, or slower using speeds of 0.25 to 0.75km/h*. That is in excellent lab circumstances; anticipate the distinction in drive effectivity to slim when the using circumstances are muddy or gritty.

*Calculated on BikeCalculator utilizing an 80kg rider, 15kg bike+gear, flat highway, 200-watt energy output

With that preamble out of the best way, some have prompt that belt drive is much less environment friendly than chain drive as a result of once you spin the cranks along with your arms, you possibly can really feel some resistance. However this check doesn’t inform the complete story.

Based on knowledge collected from three completely different lab assessments, belts do have an inferior drive effectivity at low energy outputs. It’s because a belt is all the time below stress, whereas a series can run with some slack. As we introduce extra pedal or electrical energy right into a drivetrain, a belt quickly turns into simply as environment friendly as a series.

We will see the chain has a better drive effectivity till ~120 watts energy output. Graph: Trier College

The Trier College lab check (impartial) suggests the crossover level is at 120-watts energy output, whereas the Friction Info lab check (impartial) suggests it’s up over 200-watts. And Common Transmissions (non-independent) discovered the crossover to be at simply 30-watts. Both approach, most cyclists will hit these crossover factors.

Common Transmissions (or UT) has not too long ago printed some further belt and chain knowledge that’s value discussing.

Please notice that UT developed the unique belt drivetrain in partnership with Gates, and they’re additionally the distributor for Gates Carbon Drive in Europe. In consequence, we should always stay skeptical of the chain effectivity, resistance, and put on price knowledge – as these numbers can fluctuate considerably between chain fashions and lubricants used.

Alright, let’s get onto the fascinating findings.

A graph exhibiting the drive effectivity of each new and worn chains and belts. Picture: Common Transmissions

The primary is with regard to the drive effectivity on worn chains and belts.

The info counsel that worn belts run extra effectively than worn chains after each 5,000km (100% put on) and 10,000km (200% put on). In reality, the belt at 10,000km was operating extra effectively than the chain at 5,000km. That is just because the chain will get longer over time and may now not mesh as effectively with the sprockets.

A drive effectivity graph exhibiting a worn chain below three situations in comparison with a belt on the similar distance. Picture: Common Transmissions

How about if we use a brand new chain with the 5,000km previous sprockets? That’s additionally much less environment friendly than a belt after the identical distance.

However notice that you just’ll undergo a number of chains over the lifespan of 1 belt. This implies the effectivity of a belt drivetrain regularly reduces over time, whereas the chain will leap between 96% and 98% relying on how worn it’s.

A graph exhibiting the drive effectivity of a belt below three completely different tensions. Picture: Common Transmissions

The opposite fascinating check was relating to belt drive effectivity at low, medium, and excessive tensions. This check reveals that low stress is greatest at most energy outputs, however by 50 watts, all belt tensions are inside 1% – suggesting stress performs a minor position in biking pace.

Are belt drive bikes value it?

In the event you’ve made it to the tip right here, I feel you deserve an honorary Ph.D. in belt drive. Congratulations!

Many world bike travellers have now demonstrated (within the worst using circumstances potential) that belt drive bikes are long-lasting, robust, and low upkeep.

In the event you prioritise sturdiness and ease of use over all the pieces else, belt drive is the perfect drive possibility out there. I like to recommend belts for touring, commuting, bikepacking, cargo hauling, and leisure using, particularly.

Nevertheless, belts usually are not the perfect for each utility. In order for you the quickest and lightest bike, you’ll nonetheless be greatest served by chains and derailleurs.

To be taught extra about gearboxes, try my articles on inexpensive Shimano inner gear hubs, in addition to Rohloff hubs, Pinion gearboxes, and Effigear gearboxes. There are additionally a bunch of recent gearboxes coming in for 2023.