I have two MTBs and one is slower than the other.
Bike1 has Deore derailleurs and a double chainring with 10 sprockets and Shimano hubs. Which has a great speed irrespective of the gear combination.
Bike2 has Acera derailleurs with a triple chainring and 8 sprockets with acera and Quando hubs.
The second bike is much slower than the first one in terms of speed.
My question is, apart from physical strength, which is more important for speed, a hub or drivetrain?
I want to upgrade my bike. Can anyone guide me to get more-or-less the same speed. Both bikes are from same brand and almost identical in terms of dimensions and shape.
Please help me to understand the science.