With the stated rates and the target motor, it would last a life.
It's a retro-direct gearbox with a ratio of 2:1
I used to think that maybe a slightly closer ratio would be more ideal, but now...If my standard cruising speed on a street commuter is 28-ish MPH (45 km/h), then I am now convinced that a max top speed that is higher is not a bad thing. In fact, max efficiency is often near 80% of max top speed (IIRC).
So, if actual top speed is near 33-MPH, and my most-often used cruise speed is 28-MPH, a 2:1 gearbox would put my "hill climbing" gear at a max 16-ish MPH, with max efficiency near 13-MPH?
Yes, that's the main idea and objective of the gearbox I suppose; the 2:1 factor is a good thing for the motor range target stated by Miles...Plus, in the real world, a 2:1 mech reduction will result in slightly closer speed and torque values for obvious reasons.
On that topic, is important to note that the GB is a 50% in 1st and not a 2x overdrive in 2nd. This is a natural approach but probably means also a gearbox projected to extend, occasionally, or better: -often but not continuously- the max climb or load ability, of a motor that could otherwise stall or work on terribly inefficient spots.....and not to extend the upper speed band of a motor
crossbreak wrote:a tiny 3220 is just a joke with its <10Nm torque abilities.
that would probably never stall at any grade, yet, with the right single speed ratio.
Having 1500rpm and 40Nm as limits in mind, a 3220, after a 5:1 belt reduction (7Nm peaks and 8000rpm=>35Nm and 1600rpm) is actually the most powerful kind of motor to mate the gearbox with. And you cannot couple them inline, because of the overrun....
It is perfect for Miles Motor or eventually for a 3210 with the right reduction....and would be very interesting for cargo applications, even with smaller motors, if not for the rollback problem.
The Ideal motor would be of course one capable of the 40Nm and 1500rpms limits, without any reduction....