চেইন ও স্প্রকেট কখন বদলাবেন — মাইলেজ ও ওয়ার্নিং সাইন

Your chain and sprockets wear as a matched set. Replacing just one — say, a new chain on old sprockets — wears out the fresh part within weeks. Here's how to tell when the kit is due and what riders on the major commuter bikes should budget.

Five signs your chain kit is finished

• Slack that returns quickly. If you adjust the chain and it goes loose again in 500 km, the links are stretched.
• Hooked or pointy sprocket teeth. New teeth are symmetrical; worn teeth curl to one side like a shark fin.
• Rust that returns after cleaning. Once the O-rings dry out, moisture reaches the rollers and rust becomes permanent.
• Tight spots. Rotate the wheel slowly — a chain with tight and loose sections has seized links.
• Chain lifts off the rear sprocket. If you can pull a link away from the sprocket by more than half a tooth, replace immediately.

Typical intervals

• Bajaj Pulsar 150 / Discover 125: 22,000–28,000 km on a standard non-O-ring chain.
• Suzuki Gixxer / TVS Apache: 25,000–32,000 km.
• Yamaha FZ / R15: 28,000–35,000 km with the O-ring chain fitted from factory.
• Honda CBR 150R: 30,000–40,000 km with regular cleaning and lubing.

Dusty routes, monsoon riding, and skipping monthly lubing can halve these numbers.

Chain kit prices in Bangladesh (2026)

• Pulsar / Discover complete kit: ৳2,200–3,200 (standard), ৳3,800–5,000 (O-ring).
• Apache RTR / Gixxer kit: ৳2,800–3,800 standard, ৳4,500–6,500 O-ring.
• FZ / R15 kit: ৳3,500–4,800 standard, ৳6,000–8,500 O-ring.

Compare listings under the chain & sprocket category. O-ring chains cost more but nearly double the service life if you clean them monthly.

Fitting tips

Always replace the chain and both sprockets together. Torque the rear sprocket bolts to spec (typically 30–35 Nm on 150cc bikes) and use fresh lock washers. After fitting, set chain slack to 25–30 mm at mid-span with the bike on its side stand.