JMCHstore 50T Rear Sprocket for Mini Bikes (#40/41/420 Chain) — 6-Bolt 49mm BCD, Gold Zinc Coated High-Strength Steel

This precision-machined rear sprocket from JMCHstore is made for popular small-frame bikes such as Coleman CT100U, Mega Moto MMB80/105, Baja Doodle Bug DB30, Motovox MBX10 and several 105–212cc style mini bikes. Finished with a corrosion-resistant gold zinc coating and cut from high-strength steel, the 50T sprocket aims to deliver consistent power transfer while resisting wear and rust in everyday riding conditions.

Will this sprocket fit my mini bike?

If your bike uses a #40, #41 or 420 chain and a six-bolt mounting pattern with a 49mm bolt circle, the JMCHstore 50T is likely compatible. It’s sized for a 37mm center hole and six 6.5mm mounting holes, so confirm those measurements against your wheel hub before ordering.

• Chain size: #40 / #41 / 420
• Teeth count: 50
• Bolt circle diameter: 49mm (center-to-center)
• Center hole diameter: 37mm; six 6.5mm mounting holes

How does this sprocket affect ride performance?

The 50-tooth design finds a middle ground between torque and top speed, giving improved acceleration without a large sacrifice in top-end. Precision-cut teeth and balanced construction reduce chain slip and smooth power delivery, which helps drivetrain components last longer.

• Balanced gearing for acceleration and speed trade-off
• Precision-tooth machining minimizes wear and vibration
• Gold zinc plating reduces corrosion and friction-related issues

Is this sprocket durable enough for upgraded engines?

Yes — JMCHstore engineers this sprocket from high-strength steel to endure the higher loads produced by 212cc and larger engines commonly used to upgrade mini bikes. The gold zinc finish improves resistance to rust and environmental exposure, extending service intervals compared with untreated steel.

• High-strength steel construction for heavy loads
• Gold zinc coating for weather resistance
• Designed to handle higher RPMs without deformation

What installation and maintenance should I expect?

Installation is straightforward if your hub matches the sprocket’s bolt pattern and center bore. Routine maintenance includes keeping the chain lubricated and inspecting mounting bolts for torque; a well-aligned chain further reduces wear and maximizes sprocket life.

• Match bolt circle and center bore before installation
• Use correct bolt torque and thread locking as needed
• Regular chain lubrication and alignment checks prevent premature wear

Who is this sprocket for? Riders who modify or maintain small-frame mini bikes and want a reliable, mid-range gearing option will benefit most from the JMCHstore 50T rear sprocket. It’s suited to hobbyists, parts resellers, and anyone running popular models like the Coleman CT100U, Mega Moto, Baja Doodle Bug DB30, Motovox MBX10, or similar compact 105–212cc machines — provided the wheel hub uses a six-bolt pattern and a #40/#41/420 chain. Note: this sprocket does not fit go-karts that use different mounting standards.