Driven Racing USA

Driven Racing 428 EVO TECH Rear Sprocket | Honda Grom

SKU 169-542 40T
$35.00
Shipping calculated at checkout.
Options: 40T
Description
Fine-tune your Honda Grom or Monkey 125's gearing with the Driven Racing EVO TECH #428 rear sprocket. CNC-machined and case-hardened in the USA for maximum durability and smooth power delivery. Available in 34T–40T to optimize for acceleration or top-end speed.Important — bolt pattern changed in 2022:
  • 2014–2021 Grom / Monkey 125: use 34T, 35T, or 36T
  • 2022+ Grom / Monkey 125: use 38T, 39T, or 40T
  • Chain size: #428
  • Inner diameter: 58mm
  • Diagonal bolt spacing: 89mm
  • Material: case-hardened steel
  • Made in USA by Driven Racing
Also fits (428 chain): Honda CR 80R (1985), CT 70 (1969–1994), XL 80S (1980–1986), XR 70R (1997–1999), ZB 50 (1988)Gearing guide:
  • Stock rear sprocket: 34T (2021 and earlier Grom) / 38T (2022+ Grom)
  • Adding rear teeth — more low-end torque and acceleration, better for urban riding and short straights
  • Removing rear teeth — higher top-end speed, lower RPMs, better for open road and long straights
  • Removing 1 front tooth ˜ adding 3 rear teeth
California Prop 65 Warning: www.p65warnings.ca.gov
Product Diagrams
Features
  • CNC-machined and case-hardened steel — maximum durability and reduced rotating mass
  • Available in 34T, 35T, 36T, 38T, 39T, 40T for precise gearing tuning
  • 2014–2021 Grom/Monkey: 34T/35T/36T | 2022+ Grom/Monkey: 38T/39T/40T
  • #428 chain, 58mm inner diameter, 89mm diagonal bolt spacing
  • Made in USA by Driven Racing
Specifications

Chain: #428 | Inner Diameter: 58mm | Bolt Spacing: 89mm (diagonal) | Material: Case-Hardened Steel | Options: 34T / 35T / 36T / 38T / 39T / 40T | Origin: USA | SKU: 169-542

Model Fitments

Honda Grom 125 (2014-2021: 34/35/36T | 2022+: 38/39/40T) | Honda Monkey 125 (2014-2021: 34/35/36T | 2022+: 38/39/40T) | Honda CR 80R (1985) | Honda CT 70 (1969-1994) | Honda XL 80S (1980-1986) | Honda XR 70R (1997-1999) | Honda ZB 50 (1988)

  • Same day shipping for orders placed before 2PM (CST) M-F
  • 30-day return period on eligible items
  • Flat-rate shipping for orders shipped to the 48 Contiguous United States.
Options: 40T
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