JT Sprockets

Online Catalogue

Aprilia 125 MX — Finland

2004

Front Sprocket

Steel Front Sprocket

Part Number: JTF394

Teeth: 16

Available Sizes: 11, 13, 14, 15, 16, 17

Rear Sprocket

Steel Rear Sprocket

Part Number: JTR5

Teeth: 45

Available Sizes: 39, 40, 41, 43, 44, 45, 46, 47, 49

Drive Chain

Pitch: 520

Length: 112

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
111314151617
Rear Sprocket393.55
+26.1%
3.00
+6.7%
2.79
-1.0%
2.60
-7.6%
2.44
-13.3%
2.29
-18.4%
403.64
+29.3%
3.08
+9.4%
2.86
+1.6%
2.67
-5.2%
2.50
-11.1%
2.35
-16.3%
413.73
+32.5%
3.15
+12.1%
2.93
+4.1%
2.73
-2.8%
2.56
-8.9%
2.41
-14.2%
433.91
+39.0%
3.31
+17.6%
3.07
+9.2%
2.87
+1.9%
2.69
-4.4%
2.53
-10.1%
444.00
+42.2%
3.38
+20.3%
3.14
+11.7%
2.93
+4.3%
2.75
-2.2%
2.59
-8.0%
454.09
+45.5%
3.46
+23.1%
3.21
+14.3%
3.00
+6.7%
2.81
standard
2.65
-5.9%
464.18
+48.7%
3.54
+25.8%
3.29
+16.8%
3.07
+9.0%
2.88
+2.2%
2.71
-3.8%
474.27
+51.9%
3.62
+28.5%
3.36
+19.4%
3.13
+11.4%
2.94
+4.4%
2.76
-1.7%
494.45
+58.4%
3.77
+34.0%
3.50
+24.4%
3.27
+16.1%
3.06
+8.9%
2.88
+2.5%

Lower gear ratios allow for higher top speeds.

Higher gear ratios increase torque for better acceleration.

Full Gear Ratio Chart (pdf)