Which gearing to maximize range?

Jetsonbike

1 µW
Joined
Mar 23, 2022
Messages
3
I have a 52V BBSHD on a full suspension mountain bike. PAS is disconnected and I rarely pedal due to bad knees. Tires are 26x3.00" knobbies. Most of my riding is fast woods riding and my gearing is great for that. Chainring is a 36T. My homemade cassette stack only has only 3 gears available...a 22T singlespeed cog (for deep mud), a Shimano singlespeed 18T cog, and an 11T cassette cog. My question refers strictly to medium speed flat road riding though, when I'm riding from home to the woods and back. For a given moderate cruising speed, say 25-30km/hr, with zero pedalling and gentle throttle application to get moving, would it be more efficient to shift to the 11T cog, or should I just leave it on the 18T cog? The shifting isn't exactly smooth with this cassette stack, so if I'm not gaining any range by shifting to the 11T, I'll stop doing it. Part of me thinks it may be just physics and maybe it's the same amount of energy either way, but I thought I'd ask the pros here. Thanks!
 
That is a good question. My first thought was to use the lowest gear possible (the 22 or 18 tooth) because motors draw less current when they can spin freely.

But... if you used the 11t cog, you would throttle back, so would that make up for it?

I think the only way to answer is to get a current or watt meter you can see while you are riding, and just try it. Or try a test loop with each, and see how much energy the charger has to put back in the battery.
 
Motors are most efficient at about 80% of their unloaded speed, and of course your power requirements are lower the slower you go. I'd be surprised if your low gear isn't the best choice for range.
 
Ok thanks guys. I guess it's safe to say the that the 11T is unnecessary. It was nice having that gear for pedalling along with the motor, but if my knees don't improve, I might just remove it.
 
Jetsonbike said:
...a 22T singlespeed
..... 18T cog,
.... 11T
The shifting isn't exactly smooth with this cassette stack....
H mmmm ....
22/18 = 0.61
18/18 = 1.00
11/18 = 1.22
Every consider a 3 speed IGH ???
If memory serves the middle gear locks the sprocket shaft directly to the hub and the gear ratios are 25% increase/decrease.
Just a thought .... :?
 
LewTwo said:
Jetsonbike said:
...a 22T singlespeed
..... 18T cog,
.... 11T
The shifting isn't exactly smooth with this cassette stack....
H mmmm ....
22/18 = 0.61
18/18 = 1.00
11/18 = 1.22
Every consider a 3 speed IGH ???
If memory serves the middle gear locks the sprocket shaft directly to the hub and the gear ratios are 25% increase/decrease.
Just a thought .... :?

I've considered it, but I'd have two rear wheels (summer & winter) to convert. I really only care about offroad performance, and there are almost no hills where I live. I stocked up on 18T Shimano cogs, but if I find a good quality economical 20T cog, I may just go singlespeed.
 
Back
Top