JT Sprockets

Online Catalogue

Betamotor 390 RR

2015 to 2021

Front Sprocket

Lightweight Self-Cleaning Front Sprocket

Part Number: JTF1901SC

Teeth: 13

Available Sizes: 13, 14, 15, 16

JTF1901SC is a Lightweight Self-Cleaning sprocket

Steel Front Sprocket

Part Number: JTF1901

Teeth: 13

Available Sizes: 11, 12, 13, 14, 15

OE Type Rubber Cushioned Front Sprocket

Part Number: JTF1901RB

Teeth: 13

Available Sizes: 13, 14

Rear Sprocket

Lightweight Self-Cleaning Rear Sprocket

Part Number: JTR210SC

Teeth: 49

Available Sizes: 45, 47, 48, 49, 50, 51, 52, 53

Steel Rear Sprocket

Part Number: JTR210

Teeth: 49 Check Availability

Available Sizes: 38, 39, 40, 42, 43, 44, 46, 55

Racelite Aluminium Rear Race Sprocket

Part Number: JTA210BLK

Teeth: 49

Available Sizes: 40, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54

Drive Chain

Pitch: 520

Length: 114

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

TeethFront Sprocket
1112131415
Rear Sprocket383.45
-8.3%
3.17
-16.0%
2.92
-22.4%
2.71
-28.0%
2.53
-32.8%
393.55
-5.9%
3.25
-13.8%
3.00
-20.4%
2.79
-26.1%
2.60
-31.0%
403.64
-3.5%
3.33
-11.6%
3.08
-18.4%
2.86
-24.2%
2.67
-29.3%
423.82
+1.3%
3.50
-7.1%
3.23
-14.3%
3.00
-20.4%
2.80
-25.7%
433.91
+3.7%
3.58
-4.9%
3.31
-12.2%
3.07
-18.5%
2.87
-23.9%
444.00
+6.1%
3.67
-2.7%
3.38
-10.2%
3.14
-16.6%
2.93
-22.2%
464.18
+10.9%
3.83
+1.7%
3.54
-6.1%
3.29
-12.8%
3.07
-18.6%
494.45
+18.2%
4.08
+8.3%
3.77
standard
3.50
-7.1%
3.27
-13.3%
555.00
+32.7%
4.58
+21.6%
4.23
+12.2%
3.93
+4.2%
3.67
-2.7%

Lower gear ratios allow for higher top speeds.

Higher gear ratios increase torque for better acceleration.

Full Gear Ratio Chart (pdf)