Online Catalogue

Derbi 125 GPR Racing

2004 to 2008

Front Sprocket

OE Type Rubber Cushioned Front Sprocket

Part Number: JTF558RB

Teeth: 16

Available Sizes: 16

Steel Front Sprocket

Part Number: JTF558

Teeth: 16

Available Sizes: 13, 14, 15, 16, 17, 18, 20

Rear Sprocket

Part Number: TBA

Teeth: 50

Available Sizes:

Drive Chain

Pitch: 428

Length: 130

Please note that the chain shown in this listing is for size reference only. For the correct chain type and grade, please refer to the vehicle's manufacturer manual.

Gear Ratio Chart

Teeth		Front Sprocket
Teeth		13	14	15	16	17	18	20
Rear Sprocket	50	3.85 +23.1%	3.57 +14.3%	3.33 +6.7%	3.12 standard	2.94 -5.9%	2.78 -11.1%	2.50 -20.0%

Lower gear ratios allow for higher top speeds.

Higher gear ratios increase torque for better acceleration.

Full Gear Ratio Chart (pdf)