Online Catalogue
Betamotor 390 RR
2015 to 2021
Front Sprocket
Lightweight Self-Cleaning Front Sprocket
Rear Sprocket
Lightweight Self-Cleaning Rear Sprocket
Steel Rear Sprocket
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
| Teeth | Front Sprocket | |||||
| 11 | 12 | 13 | 14 | 15 | ||
| Rear Sprocket | 38 | 3.45 -8.3% | 3.17 -16.0% | 2.92 -22.4% | 2.71 -28.0% | 2.53 -32.8% |
| 39 | 3.55 -5.9% | 3.25 -13.8% | 3.00 -20.4% | 2.79 -26.1% | 2.60 -31.0% | |
| 40 | 3.64 -3.5% | 3.33 -11.6% | 3.08 -18.4% | 2.86 -24.2% | 2.67 -29.3% | |
| 42 | 3.82 +1.3% | 3.50 -7.1% | 3.23 -14.3% | 3.00 -20.4% | 2.80 -25.7% | |
| 43 | 3.91 +3.7% | 3.58 -4.9% | 3.31 -12.2% | 3.07 -18.5% | 2.87 -23.9% | |
| 44 | 4.00 +6.1% | 3.67 -2.7% | 3.38 -10.2% | 3.14 -16.6% | 2.93 -22.2% | |
| 46 | 4.18 +10.9% | 3.83 +1.7% | 3.54 -6.1% | 3.29 -12.8% | 3.07 -18.6% | |
| 49 | 4.45 +18.2% | 4.08 +8.3% | 3.77 standard | 3.50 -7.1% | 3.27 -13.3% | |
| 55 | 5.00 +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.
JTF1901SC is a Lightweight Self-Cleaning sprocket