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Bicycle engineering methods pioneered in the nineteenth century are still used to this day. The double diamond frame is the best example. Pneumatic tyres are another. Close behind is the chain drive system of propulsion.
The belt-drive system is an alternative which offers both mechanical and practical differences which may be more suitable for the 21st century pedaler.
What is a Belt Drive?
The belt drive is a replacement for the traditional chain drive system. A one-piece unit made of synthetic materials, reinforced with carbon fibre with equally spaced teeth, rotates around a ring at the crank and a single sprocket at the rear wheel.
Propulsion comes via rotating the cranks forward as usual. The tension required is picked up by the belt drive system and the energy created is transferred to the rear wheel.
There are no moving parts to the belt, no pins and rollers as seen on a traditional bike chain.
Belt Drive vs Chain Drive Bike
Chain drive bikes have kept bicycle wheels turning for a hundred years. In spite of this, overall cycling design has advanced rapidly, with hundreds of start-ups and entrepreneurial zeal everywhere.
This move attracts new ideas and investment. Until now, the downsides of the belt drive system outweighed the positives. As cycling now branches out into specific niches such as urban only riding on flat roads, the belt drive system appears more attractive.
Belt Drive Bike [PROS + CONS]
|No need for lubrication||Split frame needed|
|Little or no maintenance||Steeper upfront cost|
|Long lifespan||Hub or crank gearing only|
Chain Drive Bike [PROS + CONS]
|Compatible with every frame||Driveline isn’t always straight|
|Easier to find spares||Mechanically subject to multiple stresses|
|Would be easier to repair if required||Chain admin is constant|
Belt vs Chain Differences
The belt drive system is terrifically clean and tidy. You don’t need any oil to keep it moving smoothly. This is a major advantage in keeping your clothes (and those of commuters around you) free of wandering lubrication.
A chain drive needs consistent administration. It really needs to be free of excess lubrication, dust, moisture and mud. There are so many working parts to a derailleur-geared system that also need attention. It can soon become quite obsessive if you are listening out for noise, or evidence of inefficiency.
The belt does not have any moving parts. There is little or no maintenance or running costs in owning a bike once it’s fitted. You might need to remove large specks of mud from the belt and sprockets – but only with a damp rag.
A chain drive utilises a lot of moving parts. Breaking down one of the 120 or so links gives you pins, outer plates, inner plates and rollers. When any one of these gets filled with road grit and grime, your chain will not work properly.
One other advantage comes with the belt drive’s longevity. Fewer moving parts and very limited wear will give a longer lifespan than a traditional chain, ridden under the same constraints. It’s thought that a belt drive will last three times longer than a chain.
A belt drive is also much quieter than a traditional chain.
You cannot split the belt to remove it from the bike. A special frame is needed to accommodate it. The belt is designed to stay on the bike but if not, you need to open the frame up, usually at the chainstay or seat stay and pull the belt out through the gap.
The frame also needs to demonstrate little or no sideways flex. This is because the belt drive relies on an entirely straight line to run efficiently. The frame is required to be stronger to limit this movement – therefore more specialist and not ‘off the shelf’ or from a traditional production line.
Belt drives cost more upfront than chain drive systems and there are inevitably fewer bike shops to service them or sell spare parts. When something goes wrong, the bike might be out of action longer than it would be with a chain drive system. Repair on the road is achievable with a chain drive system.
The chain drive has been around so long that most bike designs are made with this system in mind. The chain drive is therefore suited for most new, second-hand and retro bikes. Fitting any of the components in a chain drive requires little planning. The argument for this is of course linked in some way to the fact that the chain needs replacing relatively frequently.
Spare parts, replacement parts and servicing is readily available and all bike shops will usually be able to get hold of any type of chain, lubricant, sprocket and chainring that you could need. There are some minor differences between a BMX chain and a road bike chain.
A belt drive is tight – they are pre-tensioned and have no slack. They cannot move up and down a selection of rear sprockets using a derailleur. You can have gears when you use a belt drive system. They are simply moved to the hub. The range of gears is fewer than you can get with a chain drive system.
Unless you ride a fixie or single speed, or hub gearing, the chances are you will use a derailleur at the rear of the bike to change gear. This means that a chain will run at an angle between the front and rear of the drivetrain. This angle creates friction and more noise. When you run a drivetrain at an angle it becomes inefficient.
Are Belt Drive Bikes Faster Than Chain Drive?
No. Belt drive bikes are actually slower than chain driven bikes when the same amount of power is used by the rider, as chain driven bikes actually provide less friction which can slow you down.
The headline figure shows that (via the friction created in their use) that chains consume less energy (34.6%) than belt drives. This study produced the result and is useful in that it identifies how the performance and efficiency of belt drives and chain drives operate under the same conditions.
Which is Better: Chain Drive vs Belt Drive
Users of e-bikes, long-distance touring bikes and urban commuting bikes are coming around to and advocating the use of belt drives. Even folding bikes have belt-drive options. Sportier riders, who need a wider gear range for climbing mountains and those who use suspension frames are favouring chain drive systems.
Better really depends on use and need. If cycling is a lifestyle choice – a clean, transportation-only substitute for taking the car, bus or subway then this fits the niche of cycling where belt-drives seem to sell the most.
The chain drive is still favoured in the more active pursuits and sportier side of cycling tends to rely on minor tweaks and adjustments to frames, swapping out parts to suit terrains or race conditions. You do tend to get more gearing options with chain drives which might help going up hills or holding a higher top speed.
The outlier comes in the shape of those super high-mileage cycling touring explorers who need as little distraction and maintenance as possible. This community has a growing number of advocates for belt-drive systems.
Should You Buy a Belt Driven Bicycle?
If your daily ride is elegant, urban, homogenous and you see your bike principally as a substitute for a train, car or bus journey, then a belt drive bike could easily work for you. Electric commuter bikes which use the mid-motor system are coming to rely on belt-drive systems.
The steeper up-front cost and relatively high cost of parts might equate to you taking a car in for its biennial service. They definitely fit a lifestyle where functionality and simplicity of transportation is a priority over riding fast, beating Strava segment times or getting dirty on a bike at the weekend climbing on trails or steeper roads.