Chainless Bikes: What is a Shaft Drive Bike and Pros and Cons

Chainless bikes are not a new invention. As early as the 1880s manufacturers were experimenting with shaft drives as a clean and low maintenance alternative to chains. Unfortunately, they never really caught on. Chains and derailleurs have been the standard drivetrain option for over a century at this point. There is good reason for this. Chains are affordable, lightweight, efficient, repairable, and easy to find in bike shops around the world.

A number of companies still offer shaft drive bikes today. There are also a couple of new and interesting shaft drive designs in development. In this guide, we’ll take a look at chainless bicycles. We’ll compare shaft drive vs chain drive and talk about the advantages and disadvantages of both systems. We’ll cover efficiency, weight, parts, performance, cost, and more. Finally, we’ll take a look at some other types of chainless bikes including belt drive, digital drive, string drive, and hydraulic drive.

What is a Shaft Drive Bike?

A shaft-drive bike is a type of bicycle that uses a driveshaft instead of a chain to transmit power from the pedals to the rear wheel.

When you pedal a shaft drive bike, you’re turning a bevel gear. This gear is located where the chainring would be on a normal bike. This gear meshes with a gear on the driveshaft. The driveshaft turns another bevel gear at the other end, at the rear hub. This gear turns the rear wheel to propel the bike forward. The drive shaft runs from the cranks to the rear hub.

the driveshaft and bevel gears are usually housed in an aluminum case on the right side of the rear wheel. This case doubles as the right chainstay. In other words, the driveshaft system is built into the frame of the bike.

There are no exposed moving parts on a shaft drive bicycle. All of the gears are sealed in a housing. This makes the system look clean and minimalistic. It’s also very compact. They are clean as well. There is no greasy chain. These systems are safe and reliable as well. There are no skipping gears.

A shaft drive bicycle can be single speed. They can also use an internal gear hub for multiple speeds. Shaft drive bikes can also be made so you can backpedal to brake, like you can on a fixed gear bike. Some models have a freewheel mechanism.

Shaft drive systems are used in the automotive industry. Many cars, trucks, motorcycles, and ships use shaft drive systems. They also have many industrial applications. Shaft drive systems are useful because they are very durable and long-lasting. Bicycles with shaft drives have also existed for over 130 years.

Shaft Drive Vs Chain Drive

Drivetrain Efficiency

Shaft drive bikes are less efficient than chain drive or belt drive bikes. The loss of energy comes from the change in the direction of the rotational force.

There are two places where a shaft drive systems change rotational direction. One is at the cranks and the other is at the rear hub. You lose energy when the direction of rotation changes. This reduces efficiency.

Chain drives are more efficient because they don’t change the direction of rotation. You pedal in the same direction that the rear tire rotates. This is more efficient.

There isn’t much data on the efficiency of shaft drive vs chain drive bikes but studies have been done on motorcycles. The power loss of a shaft drive is as high as 25%. To compare, the power loss of a chain drive is as little as 3%.

I recognize that bicycles and motorcycles are different machines but this shows that shaft drives are less efficient than chain drive systems. Shaft drives work great on motorcycles because the efficiency loss can be made up for with a larger motor. You can’t make up for the efficiency loss on a bicycle. On a shaft drive bike, you’ll have to work harder to achieve the same performance as you could get on a chain drive bike.

A single speed chain drivetrain can be up to 99% efficient. Belt drivetrains are up to 98% efficient. To compare, a shaft drivetrain would be around 92% efficient. This is under optimal conditions.

This difference in efficiency may seem minimal. For a short ride, it is. For a longer ride, every bit of energy loss is important.

Assume a rider who weighed 190 lbs rode up a hill with a 5% grade for one hour with a shaft driven bike. The same rider then made the same ride with a chain drive bike. During both rides, they output around 150 watts of power. The rider would be around 4 minutes slower on the shaft drive bike.

It’s important to note that chain drives lose efficiency when they get contaminated with dirt, sand, mud, and water. Chains also lose efficiency when they go out of adjustment and when they begin to wear out and stretch. While riding in wet and muddy conditions, a chain drive may drop to 93% efficiency.

Because shaft drives are completely sealed, they don’t lose efficiency in rugged conditions. Mud, sand, and water can’t enter the drivetrain. They also don’t wear over time or go out of adjustment. This means, a shaft drive system could be just as efficient as a chain drive in dirty and wet conditions. A shaft drive system could also be more efficient than a poorly maintained chain drive.

Winner: Chain drives are more efficient than shaft drives.

Bike Weight

Shaft drive bikes are heavier than chain drive bikes. On average a shaft drive bike will weigh 1-2 kg (2.2-4.4 pounds) more than a comparable chain drive bike.

Shaft drive bikes are heavier because a shaft drive requires heavy-duty components. Heavy gears are required to handle the extreme torque generated by the rider while starting from a stop or while climbing hills.

The force on the gears is a challenge for shaft drive bikes because they use small-diameter bevel gears. The small gear size means there is a lot of torque on the gear teeth. The gears that are used must be strong enough to handle the torque without getting stripped or wearing down prematurely.

Chain drives use larger gears which disperse the torque over a larger area. This puts less stress on the gears.

To get more technical, the moment arm in a shaft drivetrain is around 4-8 times shorter than the moment arm in a chain or belt cog. A moment arm is the distance between a rotating axis, like a wheel, and a force being applied to that axis, like when you’re pedaling your bike.

The longer the moment arm, the more leverage you have to create that twisting effect with less force. In a shaft-based drivetrain, the moment arm is far shorter than in a chain or belt system. It needs to be designed to handle more force to compensate.

Engineers need to design the shaft drive to withstand a lot of force. The forces can cause excessive wear and tear on the bearings and bevel gears. This can cause the gears to wear out quickly if they aren’t engineered to the necessary specifications.

Winner: Chain drives are far lighter than shaft drives.

Proprietary Parts

One of the biggest drawbacks to chainless bikes, in my opinion, is that they have lots of proprietary parts. The shaft drive system and the entire frame that the system is built around are proprietary. There are very few standard parts in the drivetrain.

If you have a problem with your shaft drive system or if you need to buy a replacement part, you’ll have to go to the manufacturer to buy the parts you need. This can be a problem if the manufacturer goes out of business or stops producing a particular part when the bike goes out of production. You might be out of luck. Finding a replacement bevel gear could be a real challenge. You also can’t buy parts at your local bike shop. Most bike shops don’t carry shaft drive bikes and replacement parts.

If you can’t get the parts you need, you can’t simply convert a shaft driven bike to a chain drive. This is because the frame is specifically designed for a shaft drive. The frame is only compatible with a shaft drivetrain.

With a chain drive bike, most parts are universal. If a chain, cassette, chainring, derailleur, or shifter breaks or wears out, you can just go to the nearest bike shop and buy a replacement.

Winner: Chain drive bikes have fewer proprietary parts than shaft drive

Gear Alignment

One major issue for shaft drivetrains is gear alignment. For the drivetrain to operate smoothly and efficiently, the gears need to be aligned perfectly.

This is much more difficult when using a shaft drive than a chain drive because a shaft can’t flex like a chain can. It’s completely rigid. If the gears aren’t aligned correctly, they will wear quickly. The drivetrain also won’t operate smoothly and efficiently.

The main issue is frame flex. Under load, bike frames flex a little bit. You can cause frame flex when you pedal hard, corner hard, or overload the bike. This can push the bevel gears out of alignment. With a chain drive, the flexibility of the chain allows the drivetrain to absorb some of this frame flex. It doesn’t matter if the gears are slightly out of alignment.

With a shaft drive, the frame needs to be extra stiff to reduce flex. If the frame isn’t stiff enough, the gears won’t mesh correctly. Even a small amount of flex can cause issues.

One potential solution to frame flex is to use CV joints (constant velocity joints). This would allow for frame flex. The problem is that adding CV joints to a bike’s drivetrain adds more friction. This reduces efficiency. It also increases the weight and complexity of the drivetrain.

Another issue is that shaft drivetrains must be manufactured very precisely so the gears mesh property. Tolerances must be extremely tight. If the gears are misaligned, the bike be inefficient and the gears will wear out quickly. In addition, it must be possible for the rider to re-align the rear bevel gear after removing and installing the rear wheel after repairing a flat. This makes shaft drive frames harder to engineer and manufacture.

It is possible to design a shaft driven bike that maintains proper gear alignment. The problem is that it requires a stiff frame and tight manufacturing tolerances. This substantially increases costs.

Chains and derailleurs are far easier to work with. They don’t require nearly as much precision to manufacture or adjust.

Winner: It’s easier to maintain proper gear alignment with a chain drive bike.

Performance

Chain drive bikes offer better performance than shaft drive bikes. We know this because all professional cyclists still use chain drivetrains. If shaft drivetrains were faster, they would use them.

Chain drive bikes offer faster acceleration, higher top speeds, and greater efficiency because the chain does not absorb as much energy when you pedal. You can deliver more power to the rear wheel with a chain driven bike.

There is one situation where a shaft drive system may offer better performance. That is riding in extremely muddy and wet conditions. Because shaft drivetrains are sealed, contaminants can’t get into the drivetrain and create extra friction. A shaft drive may be a bit more efficient when it’s caked in mud or snow. Still, all mountain bikers use chain drive bikes. The conditions where a shaft drive would perform better are extremely uncommon.

Winner: Chain drive bikes offer better performance than shaft drive bikes.

Maintenance

One of the biggest benefits of a shaft drivetrain is that it requires less maintenance than a traditional chain drivetrain. This is because shaft drives are fully enclosed and sealed. They are protected from dirt, mud, rain, sand, snow, and other contaminants. There are no exposed parts. You never have to clean and lubricate it. In addition, shaft drive bikes don’t require any adjustment.

After a shaft drive bicycle is set up, there is really no drivetrain maintenance required. The drivetrain will run for thousands of miles without needing to be cleaned, lubed, or adjusted. This makes shaft drive bikes a good choice for commuters, urban cyclists, and people who want a low-maintenance bike.

One of the biggest drawbacks of chain drivetrains is that they require quite a bit of maintenance. You have to clean and lube the chain regularly to keep your bike running efficiently and to get the most life out of your chain and cogs. You’ll need to use a rag and a degreaser to remove dirt and debris from the chain. You’ll also have to apply some lube to keep the chain running smoothly. It’s a messy job. You’ll need to clean your chain every 100-150 miles. For the average cyclist, that will mean every week or two.

Chain drivetrains also require more frequent adjustment. If the derailleurs aren’t properly adjusted, they can cause the chain to skip or fall off the cassette or chainring. The chain could also rub on the front derailleur and reduce efficiency. To adjust the derailleurs, you’ll use the barrel adjusters to fine-tune the shifting. Alternatively, you can take the bike to a bike shop if you’re unsure of how to do it yourself. You’ll probably only have to adjust your derailleurs once per year. Maybe less.

Over time, the chain and cassette will wear out and need to be replaced. A chain wear gauge can be used to determine when the chain has stretched too much and needs to be replaced. A chain usually lasts 1500-2500 miles if it’s properly maintained. A cassette will last for 2-3 chains.

One drawback of chainless bikes is that it is harder to find someone who can work on the bike if something breaks. You can’t just take a shaft driven bike into any bike shop for maintenance. You’ll need to find one that is capable of working on your specific bike.

It’s far easier to find someone to maintain your chain drive bike. Any bike shop can adjust your derailleurs or replace your chain or cassette. This makes chain drive bikes the better choice for riding in remote areas. If something breaks, you can always find someone who knows how to work on it.

Of course, with both types of bikes you’ll have to do other routine maintenance such as replacing the brake pads, cables, tires, tubes, etc. as they wear out and keeping all bearings greased.

Winner: Shaft drive bikes require much less maintenance than chain drive bikes.

Safety

Shaft drive systems can be safer than chain drive. This is because the system is fully enclosed. You don’t have to worry about your pant leg, shoelace, or luggage straps getting caught in the drivetrain.

On chain drive bikes, loose clothing or loose luggage straps can get caught in the chain. This could cause an accident. Of course, it could also damage your clothes and bike. This is particularly dangerous on fixed gear bikes because you can’t stop pedaling.

Winner: Shaft drive bikes are safer.

Cost

Chain drive bikes are cheaper than shaft drive bikes. The main reason is that chain drivetrains are much more common. Millions are produced. Manufacturers can use economies of scale to bring the cost down. The parts can all be bought off the shelf. They don’t require proprietary parts. They can also be manufactured with less precision. This all brings costs down.

You can buy an entry level chain drivetrain for less than $300. A mid range drivetrain might cost $600-$800. High end models might cost $1500-$3000. Replacement parts are also affordable. You can buy decent chains, derailleurs, and cassettes for $20-$30 each. Chainrings start at around $50. This lower cost makes chain drive the better choice if you’re on a budget.

Shaft drivetrains require proprietary components that aren’t available off the shelf. Manufacturers need to make all of the drivetrain components for their shaft-drive bikes, including the frame. As a result, they’re more expensive to produce and purchase.

Winner: Chain drive bikes are cheaper than shaft drive bikes.

Compatibility and Parts Availability

Parts compatibility on chain drive bikes is excellent. A wide range of companies offer chain drive components. Many components are cross compatible. For example, if you have a Shimano groupset, you can use a Sram cassette in most cases. When your chain wears out, you can replace it with a chain from pretty much any brand, as long as it’s the correct size. If a part wears out, you can almost always find a replacement. You can even find replacement parts for chain drive bikes that are decades old.

It is also possible to convert a chain drive bike to belt drive if you choose. You can also install an internal gear hub on a chain drive bike. There are lots of component options available to you.

Compatibility on shaft drive bikes is poor. If you want gears, your only option is to use an internal geared hub. You can’t use derailleurs or a Pinion gearbox. When a shaft drive component wears out, you have to replace it with the same part from the manufacturer. There are no third party parts available. You’ll usually have to order parts online.

If you have a frame that is designed for shaft drive, it will always be shaft drive. You can’t convert it to a chain drive or belt drive.

Winner: Chain drive bikes offer better compatibility. Parts availability is also better.

Looks

Chainless bikes offer a clean and minimalist look. The drive shaft is housed inside the frame. The gears are housed inside the hub. This makes the bike look sleek and streamlined. There are no exposed drivetrain components. It’s a beautiful design.

Chain drive bikes don’t look quite as clean. The chain, derailleurs, and gears are all exposed. This makes the bike look more complex.

Winner: Chainless bikes have a cleaner look.

Versatility

Chain drive bikes are more versatile. One reason is that there are more component options available. You can upgrade to a belt drive and internal gear hub if you choose. There are endless gearing options available for all different types of cycling. You can also use a chain drive bike for all types of cycling including touring, competitive cycling, mountain biking, commuting, road riding, etc. You could buy one chain drive bike and use it for racing, commuting, and exercise. If you can only own one bike, a chain drive bike is the best option.

Shaft drive bikes are a bit less versatile. They are really only useful for urban riding and commuting. They aren’t efficient enough for competitive riding or long distance riding. There also aren’t any upgrades you can make to the drivetrain.

Winner: Chain drive bikes are more versatile than shaft drive.

Consistency

Shaft drive bikes offer more consistent performance than chain drive bikes. This is because the drivetrain is sealed from contaminants. Riding through the mud will not affect the drivetrain’s performance. The drivetrain also never goes out of adjustment. It also doesn’t wear as quickly. It always performs exactly the same.

There are a lot of factors that can affect the performance of a chain drivetrain. The chain could get contaminated with sand or the lube could get washed off while riding in the rain. This creates more friction. Over time, the chain can stretch and the cogs can wear. The derailleurs can also go out of adjustment. When this happens, the drivetrain won’t operate as smoothly or efficiently. Performance is less consistent.

Winner: Shaft drives offer more consistent performance.

Longevity

Most shaft drive systems are designed to last for the life of the bike. You could get 18,000-30,000 miles (30,000-50,000 km) out of a shaft drive system. The gears, bearings, seals, and driveshaft itself are usually high quality. They don’t wear like chains.

Chains stretch over time, so they need to be replaced regularly. On average, a bike chain lasts 1500-3000 miles (2500-3000 km). You’ll also need to replace the cassette and chainring. Generally, you’ll have to replace the cassette once every 2-3 chains. Derailleurs and shifters can last decades if they’re cared for. All chain drive components can be replaced.

Winner: Shaft drivetrains last longer than chain drivetrains.

Ground Clearance

The rear derailleur on chain drive bikes hangs down from the dropout near the ground. It is a vulnerable component. It’s easy to knock the derailleur against a rock or another obstacle while riding. It’s also easy to hit the derailleur on something while transporting your bike. This could damage the derailleur or knock it out of adjustment.

Shaft drive bikes don’t have any exposed parts. They have more ground clearance. You don’t have to worry as much about causing damage to the drivetrain.

Winner: Shaft drives offer more ground clearance.

The Best Shaft Drive Bikes

There aren’t that many shaft drive bikes on the market these days. A few companies make them, though.

Honbike HF01 Commuter E-bike

This shaft drive electric folding bike is designed specifically for commuters. It offers incredibly low maintenance. Honbike claims that its shaft drive system can last for 50,000 km without needing maintenance. The shaft drive system is 100% enclosed and sealed. The bike also comes with some useful commuter features including built in lights and mudguards. The bike weighs 20.8 kg and has a range of around 40km.

Beixo Compact

This shaft drive folding bike is available in both electric and standard options. This Dutch company has a lot of experience with shaft drivetrains. They have been building shaft drive bikes since 2005.

The Beixo features a comfortable geometry and 7 speed internal geared hub drivetrain. It is available in a step-through frame model or a standard folding bike frame model.

The Driven Shaft Drivetrain

Driven Technologies is currently working on a geared shaft drivetrain. It does not use an internal gear hub. Instead, the Driven drivetrain uses a series of cartridge bearings to transfer power to a circular array of pinion gears.

This drivetrain was originally developed to reduce drivetrain friction. It achieves this by reducing the number of points of articulation in the drivetrain. It is also designed to be aerodynamically efficient.

This results in a drivetrain that is incredibly efficiency in every gear. Driven claims an efficiency of 99%. This is as efficient as a chain drive and more efficient than an internal gear hub. Even the most efficient geared hub operates at an efficiency rate ranging from 92% to 97% depending on the gear you’re using.

This drivetrain is not yet available to consumers. The company is still trying to work out some issues. A major challenge they are facing is managing low-RPM force. This requires the use of strong and durable materials so the bearings or gears don’t fail if too much force is applied. Achieving precise gear meshing also requires an extremely stiff rear frame triangle. This is another challenge the company faces. If the gears don’t line up perfectly, the bike won’t perform well.

For more info on the Driven shaft drivetrain, check out the Ceramicspeed website here.

What About Belt Drive?

Belt drives are another type of chainless drivetrain. A belt drive uses a nylon toothed synchronous belt that is reinforced with carbon fiber cords to transfer power to the rear wheel. The belt is used instead of the traditional bike chain.

Belts are paired with durable stainless steel cogs and alloy chainrings. This results in a durable, clean, long-lasting, and low-maintenance drive system.

Belt-drive bicycles are popular among commuters, bicycle tourists, and bikepackers for their low maintenance requirements and cleanliness. They do not need to be cleaned as frequently as chains. They also don’t need lube.

Like shaft drives, belt drives can’t use traditional derailleurs. They are only compatible with internal gear hubs and Pinion gear boxes. Of course, single speed is also an option.

For more in-depth info, check out my guide to belt drive vs chain drive bikes.

Are Shaft Drive Bikes Any Good?

Chain-drive bikes are the better choice for most riders because they are affordable, lightweight, easy to manufacture, and easy to maintain and repair. Chains are also extremely efficient at transferring power from the pedals to the rear wheel. You only lose 1-4% of your pedaling power. Chains and Derailleurs are also compatible with every type of bike. They are extremely versatile.

There is a reason that shaft drive bikes aren’t more popular. They are inefficient, heavy, expensive, and more difficult to repair. They are also much more difficult to engineer and manufacture. In addition, they aren’t compatible with regular derailleur gears.

That said, shaft drive bikes do have a place in the market. They’re great for people who want a bike that requires very little maintenance. With a shaft drive, you can ride for years without having to do any drivetrain maintenance. They are also great for riding in extremely dirty conditions. A shaft drive would be a great commuter bike or city bike. Some bike sharing programs use shaft drive bikes because they are so low-maintenance.

In most cases, the drawbacks of shaft drive bikes outweigh the benefits. Most riders are better off with a chain drive bike, even though they require more maintenance. If you want a low maintenance drivetrain, you’re better off with a belt drive instead of a shaft drive.

Final Thoughts

Shaft drive bikes offer some benefits. They are low maintenance and long-lasting. There are more drawbacks. They are more expensive, parts availability is poor, and they’re inefficient. They also have lots of proprietary parts. This makes maintenance and repairs more difficult and expensive.

Personally, I don’t think shaft drive bikes are the future of cycling. They will probably stick around but most likely, they will remain a niche product. There are just too many disadvantages. The technology isn’t there yet. Maybe it will improve in the future.

For most cyclists, a chain drive is still the best option. Chains are affordable, lightweight, and efficient. Belt drive is a great alternative if you’re looking for a low-maintenance chain drive option.

Do you ride a bike with a shaft drive? Share your experience in the comments below.

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