All you need to know about sprockets and chains
Understanding the basics of final gearing can alter the way your motorcycle responds. Here’s a guide on when to replace components and manipulate gearing for optimal results
“The chain is slacking a lot. You sure its fine?”, asked AlAmeen, our videographer cum track junkie during the Ducati Diavel 1260 shoot. The c hain was ‘ and after a closer inspection I found my own Ducati to be treading the same path as well. Serviced beckoned and first question to the advisor was about the chain, obviously. Turned out, it was totally fine and what followed was a deep dive into chain and sprockets. Zoom session with a few experts threw light on several aspects of final drive that really opened my eyes. Here’s my own version of Chain and Sprockets 101 for all you bikers out there. It’s a vast topic to cover so we’ll be stick ing to the basics of chain and sprocket maintenance and altering final drive.
If you’ve spent enough time on the saddle, you’d instinctively know. A worn out drive causes snatchy acceleration and engine braking, making a hell lot of noise and even resulting in clunky gear shifts. Check how the chain meshes with the sprocket and confirm that the teeth aren’t wearing into a point starting to take on a hooked appearance. Adjust the chain and pull it away from the back end of the sprocket i .e the 3 o’clock position when the chain is on the left side of the bike. If there’s significant gap between the rollers and the chain then both the parts need to be replaced.
Sprockets are designed to match the chain width, roller diameter and pitch. With prolonged use, teeth wear out and the shape/ size of the teeth changes. A worn out sprocket can be easily identified as inner and and outer faces show signs of stress. Mostly sprockets are damaged owing to misaligned chains.
If you ride an ADV and take it off the road frequently, your chain should always be free from corrosion and well lubricated. Chain tension is super important too so take a look at your instruction manual clearly and adjust the torque. Ride, change gear and use your throttle like a racer smooth and steady. Use smooth throttle transitions and develop a seamless gear technique to increase drivetrain lifespan. Remember harder you ride, faster will the sprocket give away.
Right time to replace?
On a standard road bike, chain and sprockets should be changed together ideally. Over the time, chain elongates due to wear in the pins and bushes and the distance between each pin increases slightly. The teeth on the sprockets wear at a similar rate and match the shape of the chain. The use of a new chain on an used sprocket would lead to premature wear. If you are a ‘ rider, an aluminium chain makes a lot more sense. The performance advantages provided in terms of reduced unsprung weight and gyroscopic mass are more beneficial than high wear resistance. If you’re a track rider, this is an investment you must make.
Altering final drive
The final drive (gearbox output to the rear wheel) on a chain driven motorcycle consists of a gearbox sprocket connected by a roller to the driven sprocket attached to the rear wheel. The relation between the tooth count of these two sprockets determines the final drive ratio. For standard machines, it is usually 1:3. By altering the sprocket size, you can alter the acceleration of top speed of the machine. A smaller front sprocket would improve acceleration whereas a bigger one would yield higher top speed and the opposite is true for the rear sprocket.
This would also affect the fuel economy of your motorcycle. Optimum gearing is dependant on your riding style and requirements. 'Ideal' setup can only be found after several rounds of trial and error.
Keep in mind that there’s no free lunch; for bettering the top speed, you’ll lose acceleration and vice versa.