Driven Racing 420 Rear Sprocket for Honda Grom and Monkey 125

Driven Racing EVO TECH rear sprocket for Honda Grom and Monkey 125cc with 420 chain. This is a high quality, case hardened steel replacement sprocket.

Driven Honda Grom and Monkey 125 rear sprockets for 420 chain are available in 34 tooth, which is the stock rear sprocket size for the 2021 and earlier Honda Grom. The rear sprocket size on the 2022 Grom is 38t.

Please Note: 2022+ rear sprockets are not interchangeable with 2021 and earlier model Groms. Choose 34t for 2021 and earlier models. Choose 38t for 2022 and newer models.

A few rules regarding gear ratios for sprockets are as follows:

• Drop teeth on front/add teeth to rear = increased torque, increased acceleration, wheelies, racetracks with short straights
• Add tooth on front/reduce teeth on rear = increased top end speed, open road cruising, lowers RPMs, better gas mileage, tracks with long straights
• 1 down on the front is like adding 3 teeth on the rear
• The bigger the rear sprocket, the lower the gearing and the faster the acceleration

Please click here to view our Gear Ratio Chart!

• Available in 34 and 38 Tooth
• Case Hardened
• Fits #420 Chain
• Inner Diameter: 58mm
• Diagonal Bolt Spacing: 89mm
• Made in USA!