Getting the power to the rear wheel has been a challenge for motorcycle designers since the very first motor driven cycle rolled out of the garage back in the early 1900s. Some used shaft drives, others literally used leather belts. Of course metal chains were popular too because bicycles were often the base technology for early motorcycle designs. Over the years these three primary drive units have seen great advancements in their respective domain. The most common is the chain and sprocket. This combination is most often associated with motorcycles because they are easy to build, maintain and it gives a greater freedom for tuning but they need to be replaced more frequently. The belt drive is similar in design but the belt and pulley are not commonly reproduced by the aftermarket industry. The belt drive has proven to be very durable as long as proper care and maintenance is provided. The shaft drive is the most high-tech motorcycle drive system but it also requires the least amount of maintenance. However, it does need to be serviced on a regular basis. So, let’s take a look at each drivetrain types and what it takes to get the most miles from each style.
A metallic Roller Chain
drive is the most common form of final drive on power sports equipment including both ATVs and motorcycles. Chain and Sprockets
are fairly inexpensive to manufacture and are easy to replace which makes them a perfect fit for most designs over the history of motorcycles. The chain and sprocket combination is also adaptable to nearly all operating circumstances which allows manufacturers, owners and tuners to adjust gear ratios, length, tension and all other aspects based on the needs and design of the bike. However, despite vastly improved service life offered by O-Ring
and X-Ring chain designs, it is still the system with the highest maintenance demand and shortest overall service life. Which is also why it is important to take extra care to keep your chain and sprockets clean and in good working order.
Modern, high-strength drive chain kept clean and (where directed by the manufacturer)
lubricated with the correct type of Chain-Lube
, kept properly adjusted, aligned and ridden in a reasonable way can last an amazing number of miles.
There are a great many Chain-Maintenance Tools
on the market that will help you perform the maintenance on your own. There are endless chain-lube options, there are cleaning brushes and chain alignment tools as well. The industry has come a long way the past decade or so and quite a few companies have come up with innovative ideas to make the process of cleaning, adjusting and maintaining your chain as painless as possible.Chain Maintenance Tip: Never clean your chain while the engine is running. Use a cleaning brush designed to remove gunk, debris and built up lube off your chain. Be sure to get inside the links but take care not to destroy the O-rings if that is the type of chain you have. It’s a Once you scrape the big stiff off, use a rag to get it extra clean and remove any lingering crud. Spray your chain lube on both the top and bottom of the chain, being careful to avoid getting overspray on your tire.
Vintage bikes tend to have the older style standard 520 or 530 roller chain that doesn’t have sealed O-Ring or X-Ring design and in some cases, cannot be upgraded to the newer style chains due to clearance problems at the drive sprocket. Typical size range includes 420, 428, 520, 530 and 630. O-Ring and X-Ring Chain is wider than standard Roller chain. Some vintage Triumph models are in that category, for example. So, check out the clearance issues if you plan to upgrade an old chain-drive bike to modern O-Ring or X-Ring chain before you invest in the parts. On the plus side, it is possible to do roadside repairs on old-style roller chains with a master link that can be tucked in your tool kit; that isn’t necessarily the case with new chains unless you carry the right kind of tools.
Whether replacing original equipment or upgrading to O-Ring or X-Ring chain, replace the sprockets at the same time. Sprockets that appear serviceable after being in use usually will still be worn enough to not match the contact surfaces of the new chain as optimally as new sprockets would. As a result, using old sprockets with new chain may contribute to more rapid wear and shorter chain service life.
A pre-stretched roller chain can help minimize how much the chain length changes after put into service and then requires tension adjustment. Both standard Roller chain and O-Ring/X-Ring chain will wear and stretch in use, so checking chain tension before each ride is a good idea. Excessively loose chain could be thrown from the sprocket under certain circumstances, which could not only cause loss of drive power, but could contribute to locking the rear wheel, creating a dangerous situation.
Check out chain length and link count when replacing chain; if the swing arm or other components of final drive or suspension have been altered from stock, length and link count may differ from OEM specifications. Doing your own chain replacement will require special tools like a chain breaker, press and rivet tool that is correct for the type of chain you are working on.
The early drive belts
made of leather and rivets or other combinations of material and fasteners had to handle far less horsepower than the belts of today have to contend with. But service life was still pretty limited and weather conditions could cause slippage problems. Today’s drive belts have incredible strength and durability thanks to the use of high-tech aramid or carbon fibers. Even on machines that deliver triple-digit horsepower, modern drive belts generally have long service life and require minimal maintenance and tension adjustment. Following your machine’s manufacturer’s instructions for belt maintenance, alignment and tension is essential.
Unlike typical metallic drive chains, drive belts require no lubrication, but keeping them clean can help extend service life. Grit, sand, oil leakage or other debris on the drive belt can accelerate wear and lead to premature belt failure.
A belt drive is also very quiet in use, not even creating the muted “whishing” sound of metallic chain whirling around the sprockets. When pushing a belt drive bike around the garage, some squeaking noises may be noted, but those sounds do not generally indicate any sort of problem. Severe squeaking while underway or edge wear on the belt may indicate misalignment of the pulleys, so that would need to be checked.
Most stock motorcycles that use belt final drive have some sort of debris shield to help keep gravel, sticks and other road hazard material from being able to get up into the belt travel area and between the pulley and belt. Belts are incredibly durable, but an object such as a rock between the pulley and belt is one situation that can lead to belt damage. Another situation that can develop with belts, those with loads of miles on them in particular, is ply separation where some of the drive teeth peel away from the interior side of the belt. Even this may not totally immobilize the bike, however. A tip that may be able to get you home or at least a few miles more is to tighten the belt tension and drive with smooth, gentle throttle.
Most Harley-Davidson OEM drive belts are good for over 30,000 miles and there are reports of them lasting two or three times that long. As a general rule, you should pay attention to your belts on a regular basis and consider making a swap once your odometer reaches that 30K mark. Double check your belt application in the owner’s manual, just to be on the safe side.
Changing a drive belt can be a major undertaking on most bikes and generally cannot be done on the roadside—at least not very easily. For example, the swing arm must be removed to change the final drive belt on some bikes. Unlike the sprockets used with metallic chain drive, which should be replaced whenever the chain is replaced, pulleys and belt tensioner (where equipped) for belt drive generally don’t have to be replaced whenever the belt is replaced.
In some instances, it may be possible to alter final drive ratios with belt drive in the way sprocket size changes can be made on bikes with metallic drive chain, but this may not be an option on all belt drive systems. Belt drive is common on cruisers, conventional, some sport-touring, adventure and touring bikes and is becoming more common on some sport bikes, as well.
Shaft final drive is just about the lowest maintenance drivetrain option available, but that is not to say it is a no maintenance component. Some shaft drive systems include Zerk fittings on the drive and driven ends of the drive shaft that need periodic grease. Keeping these fitting greased at regular intervals will help ensure the articulated external and even some internal parts are lubed-up. The most conspicuous maintenance area is the rear end gear set that resides within the large housing at the rear hub. This component will need some form of Hypoid Gear Oil
change over the life of the motorcycle or ATV. A general rule is that this service should be done at the same you change the engine oil. There is always a maintenance interval specified by the bike’s manufacturer so a little research can help guide you through his routine. This maintenance need can easily be overlooked older motorcycles and ATVs or vehicles because there is no guideline readily available. So, do yourself and the bike a favor and change that gear oil when you change the engine oil…just to be safe.
The Shaft Drive is not a complicated system to manufacture, but it is heavier than either a belt or chain and it tends to cost more to assemble at the OEM level. The most common shaft drive design has the driveshaft rotating at a right angle to the transmission or engine. This design is known to rob a little bit of horsepower and early versions were known to cause the bike to rise and lower on acceleration or deceleration. There is also the feared drive-line lash that has all-but disappeared in modern iterations of the shaft drive design which made on- off-throttle moves very jerky and unpleasant.
Shaft drive systems are most common on ATVs
these days. Honda introduced the Big Red in 1984 which featured the maintenance free shaft drive on a utility vehicle. It was a hit with consumers and they’ve adapted it to many other models over the years. Since then, all major manufacturers have incorporated some form of shaft-driven set-up on their ATV and some UTV designs. BMW is the brand most-often associated with using shaft-drive since the company introduced its first bike, the R32 all the way back in 1923. Since that time, the majority of their modern designs utilize this layout in their touring and sport-touring bikes. Over the years, the technology improved and other OEMs began adopting it. These days, almost every brand of motorcycle has a shaft-driven model in its line-up.
Modern shaft drive systems also tend to be very smooth and quiet, as well as long-lasting; new noises emanating from either the drive or driven end of a shaft drive system should be checked out. It may indicated the rear wheel drive spline simply needs a coating of grease (if applicable) or it may indicate excessive wear of a component that could lead to a driveline failure. As you can see, the general consensus among the three primary drive systems is that it is important to perform routine maintenance. It improves the working life of the components and is a safety precaution that is worth taking care of on a regular basis. So, be sure to follow the OEM maintenance schedule for lubrication, adjustment, cleaning and replacement so you can ride worry free for years to come.