Gear Ratio Question

Halcyon

New Member
Hello all! Can anybody explain to me why the Xduro models have a small front chainring with only 18 teeth, while the Sduros have as many as 44 teeth? This means that the Yamaha-powered models have the maximum gear ratio of 4, compared to only about 1.6 for Bosch. Given that the two motors generate almost identical torque, why such a huge difference?
 

Ravi Kempaiah

Well-Known Member
Hello all! Can anybody explain to me why the Xduro models have a small front chainring with only 18 teeth, while the Sduros have as many as 44 teeth? This means that the Yamaha-powered models have the maximum gear ratio of 4, compared to only about 1.6 for Bosch. Given that the two motors generate almost identical torque, why such a huge difference?

@Halcyon ,

The Bosch motor turn 2.5 times for each crank rotation effectively giving a 18T the same gear ratio you would get from a normal 45T chainring.
If you would like to know more about the difference between Bosch and Yamaha systems, here is a great article. You may also find this video interesting.