How does shifting gear affect battery & speed?

[Jun]

Hello, I’ve got my first eBike, Aventon Pace 500.
My bike has 8 speed gear set.
I’m trying to understand the relation between gearing & battery life/top speed.
(Confusing than I initially thought when motor comes into play. )

To be as simple as possible, let’s assume I use throttle all the time. So my top speed is fixed at 20mph.

Q1. Which gear should I use to have maximum drive range? (Using battery efficiently)

- High gear (8, the biggest one, closest one from the frame)

or

- Low gear (1, the smallest one, farthest one from the frame)

For example, if I use low gear, I’d accelerate faster but this would use more battery, especially during hill climb.

In contrast, if I use high gear, the acceleration would be slower than lower gears but since motor uses less power to crank, my range would be maximized. - less resistance to motor whether I’m on flat, incline or decline


Is this correct?

I will have the same top speed. And acceleration is not my concern. (It’s not like motorcycle so I can just start from high gear.) My goal is to have maximum range.

Q2. My bike manual says it can go faster than 20mph when I do pedaling. How can I achieve this?

- PAS 5 (Highest level of pedal assist) + Lowest Gear? All the time

or

- Somewhat different? (Like PAS 3 + one of low gears depending on situation?)

What’d be optimum combination?

—————————————————————-

When I watch video, some eBike commuters seem to only use the lowest gear and don’t shift it. I guess this’d be fastest way to get around with the best acceleration. But I think this would consume battery quickly because the lowest gear requires the most power from the motor.
I’m curious how others ride eBikes usually.
(or... just putting in the middle and forget about it? )

Thank you.

 

[Slow Rider]

Hi Jun,

You said you will be using throttle all of the time, I guess you mean throttle only without pedalling? When you are using the throttle only, the motor is operating independently of the gears and pedals and the motor is doing all of the work. The range will be the same whether you are in first gear or eighth gear. When you are using throttle only it doesn't matter which level the PAS is set to, because PAS only works when you pedal. Using throttle only is not going to use the battery "efficiently".

To use the battery efficiently, you are going to have to do some of the work and you are going to have to pedal. In general, you can maximize range by keeping the PAS at Level 1 and pedalling. PAS 1 speed is around 12mph, so if you want to go faster than that the most efficient way is to pedal faster.

Another way to maximize your range is to go slower. Here's an interesting site that calculates the watts necessary at different speeds. According to their site, at 15mph it takes 89 watts (human power plus the motor), but at 20 mph it takes 190 watts.

An interactive model-based calculator of cycling power vs. speed

An interactive calculator that lets you explore the relationship between cycling power and speed.

www.gribble.org

If you want to go faster than 20mph, the easiest thing to do would be to use the throttle to get the bike up to 20mph, and set the PAS level to 5 (max). Once you are going 20mph, start pedalling as fast as you can in eighth gear. If you can pedal fast enough and strong enough you will be able to go faster than 20mph.

 

[Jun]

Hi Jun,

You said you will be using throttle all of the time, I guess you mean throttle only without pedalling? When you are using the throttle only, the motor is operating independently of the gears and pedals and the motor is doing all of the work. The range will be the same whether you are in first gear or eighth gear. When you are using throttle only it doesn't matter which level the PAS is set to, because PAS only works when you pedal. Using throttle only is not going to use the battery "efficiently".

To use the battery efficiently, you are going to have to do some of the work and you are going to have to pedal. In general, you can maximize range by keeping the PAS at Level 1 and pedalling. PAS 1 speed is around 12mph, so if you want to go faster than that the most efficient way is to pedal faster.

Another way to maximize your range is to go slower. Here's an interesting site that calculates the watts necessary at different speeds. According to their site, at 15mph it takes 89 watts (human power plus the motor), but at 20 mph it takes 190 watts.

An interactive model-based calculator of cycling power vs. speed

An interactive calculator that lets you explore the relationship between cycling power and speed.

www.gribble.org

If you want to go faster than 20mph, the easiest thing to do would be to use the throttle to get the bike up to 20mph, and set the PAS level to 5 (max). Once you are going 20mph, start pedalling as fast as you can in eighth gear. If you can pedal fast enough and strong enough you will be able to go faster than 20mph.

Thank you so much for clarification.
You point out things that I want to know exactly.

I search dozens of seemingly related youtube videos, but somehow no one explains better than you.

I didn’t know that the motor is completely independent. (I’m from motorcycle background.)
I think that I once got faster than 12mph in PAS 1 yet I got the concept. Anyway I only have couple days of experience.

Again, I appreciate your help!

 

[rfox]

Gear affects your top speed on hub motor electric bikes if you are on PAS level. Other than that it won't affect top speed.
But when you are climbing uphill gearing especially the teeth ratio affect your climbing skill which means you will suck less juice from your battery in theory. So expect to have a better range with a better drivetrain.
When it comes to mid-drive motors, drivetrain and gear has a higher correlation with your speed, performance and battery range.