Drive Systems Deep Dive: Chain, Belt, and Shaft Maintenance

Tools Needed: Varies by drive type - rear stand, chain brush, lube, wrenches, measuring tools
Estimated Time: 15-30 minutes for chain service, 5-10 minutes for inspection
Difficulty Level: ★★☆☆☆ (Easy to Moderate)

Your final drive is the part of your motorcycle that transfers power from your transmission to your rear wheel. We touched on the three types of final drives in the “Anatomy” blog - chain, belt, and shaft - but now we're going to dig into the maintenance details. If you have a chain, you'll be servicing it regularly. If you have a belt, you'll be inspecting it carefully. If you have a shaft drive, you'll mostly leave it alone.

Understanding how your final drive works, and what kind of maintenance it needs, will help keep power flowing to your rear wheel reliably. Neglect it and you're looking at accelerated wear, poor performance, and potentially expensive – and dangerous – failures.

Chain Drives: High Maintenance, High Performance

Chain drives are the most common final drive system on motorcycles, and for good reason. They're efficient, light, cheap to replace, and easy to modify if you want to change your gearing. The downside is they require regular attention.

How Chain Drives Work

On the transmission output shaft, you will find a small sprocket called the “countershaft sprocket” or “front sprocket.” A larger sprocket is bolted to your rear wheel (called the “rear sprocket”). A chain is wrapped in a loop around both sprockets. When the transmission spins the front sprocket, the chain transfers that rotational force to the rear sprocket, which turns your wheel.

The size difference between the front and rear sprockets determines your final drive ratio. A smaller front sprocket or larger rear sprocket gives you more bottom end acceleration, but lower top speed. A larger front sprocket or smaller rear sprocket gives you higher top speed but less bottom end acceleration.

Seem complicated? Here’s how I remember it, and this special trick is for us ladies: When you want to change your sprocket gearing, think about your body. If you need more on the bottom end, it means you want a bigger rear. If you need more on the top end, you want a bigger front. Same thing for sprockets: Bigger rear (or smaller front) = more bottom end power by increasing torque. Bigger front (or smaller rear) = more top end speed.

Most riders stick with stock gearing, but it is relatively quick and easy to personalize your ride by changing sprocket sizes. Just remember that any changes you make to your gearing will have a give-and-take relationship between bottom end pull and top speed.

Chain Tension: Not Too Tight, Not Too Loose

Proper chain tension is critical. Too tight and you're putting stress on your transmission output shaft bearing, countershaft bearing, and swingarm pivot bearings. You're also making the chain more likely to break. Too loose and the chain can jump off the sprockets, bind up, or even damage your swingarm or engine case.

Your owner's manual will specify the proper slack - typically somewhere between 25-35mm (about 1 to 1.5 inches), measured at the tightest point on the chain's rotation. Why the tightest point? Chains don't wear evenly. As sprockets wear, they create tight spots and loose spots in the chain's rotation. If you set chain tension at the loosest spot in the chain, it will result in the tightest spot being much too tight, potentially causing the damage described above.

How to check chain tension: Some bikes call for you to check your chain tension when the bike is on the ground, either being held upright on resting on the sidestand. Check your manual to find the proper procedure for your model.

For most bikes, it will be something like this: Put the bike on a center stand or rear stand so the rear wheel is off the ground. You will be doing all checking and measuring on the bottom run of the chain, which is the part of the chain that hangs under the swingarm, about midway between the two sprockets. Find the tightest point by rotating the wheel and pushing up on the bottom run of the chain. Rotate the wheel about ¼ turn and push up on the chain again. Do this several times the chain has rotated all the way around at least once to determine the tightest spot. Not all chains will have a noticeably tighter spot, especially newer chains. Mark the tightest point with a piece of tape.

To measure you chain tension: Grab a flat measuring tool like a machinist’s rule, ruler, tape measure, or specific chain tension measurement tool. Place the narrow end of the tool behind the bottom run of the chain and up against a fixed part of the frame, usually the underside of the swingarm. Push the chain up from the bottom until it's tight. Take your first measurement by noting where the bottom side of the chain sits against the ruler. Let the chain relax and take your second measurement, noting where the bottom of the chain sits against the ruler. Calculate the difference between the two measurements. This is your chain slack.

Can you take your measurement reading from the top of the chain? Sure, as long as you’re still working on the bottom run of the chain and read both measurements from the top side of the chain. A common mistake is to push the chain up and take the reading from the top of the chain, then push the chain down and take the reading from the bottom of the chain. This adds the width of the chain itself to your tension measurement. If you use those readings to adjust the chain tension, it will be much too tight.

If your chain tension measurement falls outside of spec, either too tight or too lose, it needs to be adjusted. If your measurements vary wildly at different parts of the chain - like 15mm of slack in one spot and 40mm in another spot - your chain is worn out or you have a bent sprocket. Either way, the chain and both sprockets should be replaced.

Adjusting Chain Tension

Most bikes use axle adjusters - bolts on each side of the swingarm that move the rear axle backwards or forward. The adjustment process is straightforward but requires attention to detail.

Step-by-step:

1.     Loosen the rear axle nut. Don't remove it, just loosen it enough that the axle can slide in the adjustment slots.

2.     Loosen the adjuster lock nuts, if present, on both sides of the swingarm. (There are many variations of axle adjusters, but most fit two common designs: One type has a socket head cap screw at the very back of the swingarm without a locknut, while the other has a hex head bolt with a lock nut, either in front of or behind the axle. A third common style is what I call the “sea shell”; this type is an elliptical cam affixed to both ends of the axle, with numbered notches that align with a fixed pin on the swingarm. The sea shell rotates forward or backward to modify chain tension, and the numbered notches allow you to make sure both sides are properly aligned.)

3.     Turn the adjuster bolts evenly on both sides. Consult your owner’s manual to determine how your adjusters work. On some designs, turning them in (clockwise) pushes the axle back and tightens the chain, and turning them out (counterclockwise) lets the axle come forward and loosens the chain. Other designs are the opposite – counterclockwise pushes the axle back and clockwise moves the axle forward.

4.     Most swingarms have alignment marks showing how far you've adjusted each side. Keep these marks even. If one side is adjusted more than the other, your rear wheel won't be aligned with your front wheel and the bike will handle poorly. It will also lead to accelerated wear of your chain and sprockets. If your chain doesn’t have alignment marks, you will need to measure from the center of your axle to a fixed part of your swingarm (usually the back edge of the swingarm) on both sides to make sure they’re adjusted evenly. The alignment marks on your frame aren’t always precise, so it’s a good idea to double check alignment even if you do have alignment marks.

5.     Measure your chain tension. Adjust more if needed.

6.     When tension is correct and both sides are aligned, hold the adjuster bolts in place with one wrench and tighten the lock nuts (if present) with a second wrench.

7.     Torque the rear axle nut to spec. This is important! An under-torqued axle nut can work loose, and it is the axle – not the adjuster bolts – that holds your wheel in place. Your manual will specify the torque value.

8.     Check chain tension one more time. Sometimes tightening the axle nut changes things slightly.

Common mistakes: Not keeping both sides aligned. Not torquing the axle nut properly. Adjusting the chain too tight "just to be safe" (which is not safe at all). Checking tension with the bike in the wrong orientation (for example, checking on the sidestand instead of the centerstand or rear stand) as outlined in your owner’s manual.

Chain Lubrication: Often and Correctly

Chains need regular lubrication. The lube penetrates into the rollers (the bits in the center of the chain that engage with the sprockets) and pins (the bits that hold the rollers firmly between the side plates), reducing friction and wear. It also protects against rust and helps shed dirt and debris.

How often should you lube your chain? Check your owner’s manually. A good ballpark range is every 300-600 miles in dry conditions, more often in wet or dirty conditions. After riding in the rain, lube your chain as soon as you can - water displaces the lube and promotes rust.

What kind of lube should you use? There are two main types: spray-on chain lube and wax-based lube. Spray lubes penetrate well but tend to fling off at speed and attract dirt. Wax-based lubes stay on better and attract less dirt but don't penetrate as well. Use what works for your riding conditions. I prefer spray lube in dry climates and on-road riding, and wax-based lubes in dusty or dirty conditions.

Don't use WD-40 or general-purpose spray lubricants as chain lube. They're too thin and will fling off immediately. Don't use heavy gear oil or grease - they attract dirt and don't penetrate into the chain rollers.

How to lube a chain properly:

1.     Clean the chain first. Use a chain brush and kerosene, chain cleaner, or degreaser to remove old lube and dirt. A dirty chain with fresh lube on top just makes sticky mud.

2.     Let the chain dry completely if you used a wet cleaner.

3.     Put the bike on the center stand or a rear stand. If you don’t have either, you or an assistant will need to roll the bike by hand.

4.     Rest the nozzle tube of your chain lube on top of your chain, where the chain meets the lower outside portion of the rear sprocket. Rotate the wheel slowly by hand, or by physically rolling the bike forward, while spraying lube onto the chain between the rollers and pins.

5.     Do one complete rotation, hitting every link.

6.     Move the nozzle tube to lower inside portion of the rear sprocket, then repeat Steps 4 and 5.

7.     Let the lube sit for a few minutes to penetrate, then wipe off the excess. You want lube the space between the side plates and the rollers, not coat the outside of the side plate where it'll just attract dirt and fling onto your wheel.

When to lube: The best time is right after a ride when the chain is warm. Warm lube penetrates better. If you lube a cold chain, the lube sits on the surface and doesn't work as well.

Chain and Sprocket Inspection

Every time you lube your chain, take a minute to inspect it and the sprockets for wear.

What to look for on the chain:

·       Tight spots or stiff links. Grab the chain and flex it side to side. It should move smoothly. A kinked or stiff link means the chain is damaged.

·       Excessive wear. Chains stretch over time as the pins and rollers wear. If your chain is consistently running at maximum adjustment (axle all the way back in the adjustment slots), it's worn out and needs to be replaced.

·       Rust or corrosion. Surface rust on the side plates isn't a big deal, but heavy rust or rust on the rollers means the chain hasn't been maintained properly.

·       Damaged or missing o-rings. Most modern chains have rubber seals between the plates that keep grease inside; these are marketed as o-ring, x-ring, xw-ring, etc. If these seals are damaged or missing, the chain will wear much faster.

What to look for on the sprockets:

Sprocket teeth should be symmetrical and evenly shaped. As they wear, they start to hook or point like waves or shark teeth and it means your sprockets are worn out.

The wear pattern should be even across all teeth. If some teeth are more worn than others, or if one side of the sprocket is worn more than the other, you might have an alignment problem or a tight spot in your chain.

Look for broken or chipped teeth. Even one broken tooth means you need a new sprocket.

When to replace: Replace your chain and sprockets as a set when the chain is worn to the limit (check your manual for measurement specs), when the sprocket teeth look live waves, or when you find damage like broken teeth or a kinked chain. Replacing just the chain or just the sprockets means the new part will wear out the old part rapidly.

Longevity varies greatly based on the displacement of your motorcycle, size of the chain, o-ring vs non-o-ring, the tensile strength rating of your chain, etc. What is tensile strength? Let’s back up and look at your basic chain specs. Your owner’s manual will tell you what size chain your bike needs – let’s say 520x120. The number 520 tells you the distance between your two roller pins, and the distance between the two side plates. This chain will only work with sprockets designed to work with a 520 chain, and vice versa. The number 120 tells you how many pins are in your chain, which tells you how long the chain is. If you change the number of teeth in the sprocket, this will also affect the length of the chain. So far, so good, right?

But wait a minute… what if you have a 150cc bike and a 1300cc bike, and they both take 520x120 chains? Those bikes have wildly different horsepower, with wildly different demands on the chain. That’s where tensile strength comes in. The tensile strength rating tells you how much pulling force a chain can withstand without breaking. If you’ve never heard of this before, you’re not alone; most shops will talk to you about chain size a price, maybe o-ring vs non-o-ring, without ever mentioning tensile strength. For such a critical spec, it can sometimes be difficult to find. When it’s time to buy a new chain and sprockets (remember, always as a set!) don’t settle for just comparing size and price. Look for tensile strength rating, which will usually come in both pounds and motorcycle displacement. Select a chain that is rated for your motorcycle’s displacement at bare minimum; you can always go with a higher rated chain, but never use a lower rated chain. A lower rated chain will just wear quickly, ruin your new sprockets, and potentially put you in a dangerous situation.

How long will your new chain and sprockets last? As a rough estimate, a typical chain and sprocket set on a street bike might last 15,000-30,000 miles with proper maintenance. Neglect your chain and you might get 8,000 miles. Take care of it and you might get 40,000.

Why this matters for maintenance: Chain maintenance is one of the most frequent service tasks you'll do. Understanding proper tension, lubrication, and inspection prevents premature wear and potential failures. A broken chain can lock up your rear wheel or damage your engine case. At the end of the day, regular maintenance is cheap insurance.

Belt Drives: Low Maintenance, High Cost

Belt drives use a toothed rubber belt instead of a metal chain, paired with front and rear pulleys. They're quieter, cleaner, and require much less maintenance than chains. You'll find them mostly on cruisers.

How Belt Drives Work

The concept is the same as a chain - a belt wraps around a front pulley (on the transmission output shaft) and a rear pulley (on the rear wheel). The belt has teeth that mesh with grooves in the pulleys, preventing slippage.

Belts are made of reinforced rubber with aramid fiber cords (like Kevlar) for strength. They're incredibly tough, but they have limits. They can't handle as much power as chains, which is why you don't see them on high-performance bikes.

Belt Tension and Adjustment

Belts run tighter than chains - they need to be under more tension to prevent slippage and jumping teeth. Your manual will specify the exact tension, often measured by how much the belt deflects under a specific amount of force.

Some bikes have automatic belt tensioners. Others use a similar axle adjustment system as chain drives. Follow your manual's procedure.

Common mistake: Riders used to chain tension try to run belts with the same slack as a chain. Belts need to be tighter. Too loose and they'll slip or jump teeth. Too tight and you'll accelerate wear on the belt and bearings.

Belt Inspection

Belts need regular visual inspection even though they don't need the constant maintenance that chains do.

What to look for:

·       Cracks on the outer belt surface or on the inner surface, between the teeth. Small surface cracks are sometimes normal, especially on older belts, but deep cracks or cracks between teeth mean the belt is failing.

·       Missing teeth. One missing tooth, or even a portion of a tooth, means immediate replacement. A belt with missing teeth will fail catastrophically.

·       Fraying or damage to the belt edges. The edges should be clean and even.

·       Debris between the belt and pulleys. Rocks, sticks, or road debris can damage the belt. Clean out anything caught in there.

·       Pulley wear. The grooves in the pulleys should be clean and even. Worn pulleys will damage a new belt quickly.

Check your belt every few thousand miles. It takes five minutes and prevents being stranded.

Belt Replacement

When a belt needs replacement, you replace just the belt - usually. If your pulleys are worn, you'll need to replace those too. Belt replacement is more expensive than chain and sprocket replacement, and it is almost always a more labor intensive job. A good belt can cost several hundred dollars. Add pulleys and you're into serious money.

The upside is that a well-maintained belt can last 50,000-100,000 miles or more. Some riders never replace their belt.

When a belt fails, it fails catastrophically. Chains give you warning - they get loose, make noise, develop tight spots. Belts just snap. One minute you're riding, the next minute you have no power to the rear wheel. This is why inspection is so important.

Why this matters for maintenance: Belt drives are low maintenance, but they're not no maintenance. Regular inspection catches problems before catastrophic failure. Understanding proper tension prevents premature wear and slipping. When replacement time comes, the cost is high, but the intervals are long.

Shaft Drives: Set It and Forget It

Shaft drives are the most maintenance-free final drive system. There's no external chain to clean and lube, no belt to inspect for cracks. Power transmits through a shaft enclosed in the swingarm, with bevel gears at each end.

How Shaft Drives Work

The transmission output shaft connects to the drive shaft through a u-joint. The drive shaft runs through the swingarm to the final drive housing (the pumpkin), where bevel gears change the direction of rotation by 90 degrees and transfer power to the rear wheel.

Everything is enclosed and sealed, running in gear oil. No exposed moving parts, no external maintenance beyond checking the oil level and watching for leaks.

Shaft Drive Maintenance

Shaft drive maintenance is minimal but important.

Check the final drive oil level according to your manual's schedule - typically every couple engine oil changes or every few thousand miles. Most bikes have a check plug or sight glass on the final drive housing.

Change the final drive oil according to your service manual. Usually every 10,000-20,000 miles, though some riders change it with every engine oil change since it's quick, easy, and uses very little oil.

Watch for leaks. Check the final drive housing, the u-joint boots, and anywhere the shaft passes through a seal. Gear oil leaks are usually obvious - you'll see wisps of oil on the swingarm or dripping onto the ground.

Listen for unusual noises. Grinding, whining, or clicking from the final drive can indicate worn bearings or damaged gears. This is rare, but if you hear something that doesn't sound right, investigate.

Why this matters for maintenance: Shaft drives are the easiest final drive to maintain, but they're not maintenance-free. Regular oil changes keep the gears lubricated. Catching leaks early prevents running the final drive low on oil, which will destroy the gears and bearings. Final drive failure on a shaft drive bike is expensive - we're talking thousands of dollars for a replacement final drive unit.

Comparing the Three Systems

Chain drives:

• Pros: Efficient, light, cheap to replace, easy to change gearing. Transmits maximum power to the rear wheel.
• Cons: High maintenance (clean and lube every 300-600 miles), wear relatively quickly, messy
• Best for: Sportbikes, dirt bikes, any bike where performance and weight matter

Belt drives:

• Pros: Quiet, clean, long-lasting, minimal maintenance
• Cons: Expensive to replace, can't handle as much power as a chain, limited possibility for gearing changes
• Best for: Cruisers, touring bikes, riders who want low noise and low maintenance

Shaft drives:

• Pros: Very low maintenance, very long-lasting, clean, quiet, reliable
• Cons: Heavy, transmits the least amount of power to the rear wheel, expensive to replace if it fails, no possibility for gearing changes
• Best for: Touring bikes, adventure bikes, riders who want the lowest maintenance option

Common Questions

"How do I know if my chain is too worn to adjust anymore?"

If your axle is all the way back in the adjustment slots and your chain still has too much slack, it's worn out. Most bikes have about 2-3 inches of adjustment range. Once you've used it all up, time for a new chain and sprockets.

“Can I remove a link or two to get my old chain into adjustment?”

This is not a safe approach. Your chain is worn past the point of adjustment because it has stretched beyond spec, which means it can no longer safely handle the amount of power for which it was originally rated. It’s worn out, and the rate of wear will only increase if you remove a link or links. If you’re in the middle of the Sahara and need to shorten your chain to keep if from jumping off the sprockets as you limp gingerly into civilization? Sure, go ahead and cut out some links. Then replace your chain and sprockets IMMEDIATELY upon reaching a town. Outside of that kind of extreme example, please don’t ever cut links out of a worn chain.

"Can I replace just the chain without replacing the sprockets?"

Same as cutting out links: you can, but you shouldn't. A new chain on worn sprockets will wear out quickly. Worn sprockets on a new chain will wear the chain out quickly. Always replace chains and sprockets as a set.

"My belt has some small surface cracks. Does it need replacement?"

Small, shallow surface cracks are sometimes normal on older belts. What you're watching for is deep cracks, cracks between the teeth, or cracks that are growing. If you're unsure, have a shop look at it. Belts are expensive, but not as expensive as being stranded.

"How do I know what kind of chain lube to use?"

If you ride mostly in dry conditions, spray lube works well. If you ride in dusty or dirty conditions, wax-based lube attracts less dirt. If you ride in wet conditions frequently, look for a waterproof lube. Try a few types and see what works for your riding.

"Can I use a pressure washer to clean my chain?"

Not recommended. Pressure washers can force water past the o-rings and wash out the grease inside the chain. Use a brush and chain cleaner or kerosene instead. If you must use a pressure washer, keep it on a low setting and don't spray directly at the o-rings.

"My shaft drive is leaking a little oil. How urgent is this?"

Address it soon. A small leak becomes a big leak. Running your final drive low on oil will destroy the gears and bearings. If it's just a few drops, you have time to schedule the repair. If it's actively dripping or leaving puddles, get it fixed immediately.

"Should I convert my chain drive to a belt drive?"

Conversion kits exist but they're expensive and require significant modifications - new wheels, new swingarm or swingarm modifications, new brake components. Unless you have a specific reason (building a custom bike, for example), it's rarely worth it.

"How tight should my chain be?"

Follow your manual's specification, typically 25-35mm of vertical movement at the tightest point. When in doubt, slightly loose is better than too tight. Too tight causes bearing damage. Slightly loose just means you'll need to adjust it sooner.

"Can I adjust my chain on the sidestand?"

Yes, but it will only give you an accurate measurement if your owner’s manual specifies that it should be checked on the sidestand. The suspension position affects chain tension. If your owner’s manual specifies that your chain tension should be checked on the center stand or a rear stand, checking on the sidestand might give you a false reading.

What's Next

Now you understand how final drives work and what they need to stay healthy. Chain drives need regular cleaning, lubrication, and tension adjustments. Belt drives need careful inspection and proper tension. Shaft drives need oil changes and leak monitoring.

In the next post, we'll move from the drive system to another critical component: brakes. We'll cover how brake systems work, how to inspect pads and rotors, how to bleed hydraulic brakes, and when components need replacement. Brakes are safety-critical, and understanding how to maintain them properly is essential.

Coming Up Next: Brake System Maintenance: Pads, Rotors, Fluid, and Bleeding