Why do the majority of people on an ebike ride at a fairly low cadence?

Question

Around the place where I live the electric bicycle is gaining popularity and it's easy to pick those on such bike from far away not just from posture (rather stiff upper body even on steep hills) but also from their cadence: for some reason the majority (I'd estimate more than 90%) of the people I see on an ebike ride at a rather low cadence. It's hard to estimate how low but I'd say something like 30rpm; in any case: lower than any other cyclist on a normal bicycle no matter what type. So I've been wondering why and I cannot really figure it out (nor if they all do it for the same single reason). I don't really have the guts to just ride next to one and ask, also because I'm afraid to get frowning faces and answers like 'no idea'.

I was thinking it is maybe just as simple as 'because they can'. Maybe they all just think 'if it works ok spinning slowly, why spin faster'. But to me this is counterintuitive as even when I don't have to output a lot of power I'd still go for a decent cadence rather than a lower one as it just seems to work better and science seems to agree with me. And in any case I wouldn't go as low as they do. So I was thinking maybe they all were told to ride like that in the shop and/or there is some technical reason related to the whole drive system? Like it is more beneficial in terms of power usage or so? Or the bikes are just built with less gears and favouring the higher ratios?

Answer 1

There are (at least) two reasons. First, most (but not all) E-bikes use a control system that multiplies the amount of force or torque that you put into the pedals or cranks. Since power is the product of pedal speed and pedal force (or torque), increasing the torque allows the rider to reduce the pedal speed -- that is, the rider's cadence. Electric motors (can) produce full torque at any rpm, so these controllers typically modulate the torque output rather than the rpm.

Second, if a rider on an E-bike were riding at "normal" cadence for his or her speed you would be less likely to notice the rider, so your observational sample is likely to be more heavily weighted to those with lower than normal cadence.

Answer 2

In general studies have indicated that trained cyclists use pedaling frequencies higher than 90 rpm whereas untrained cyclists prefer frequencies around 60 rpm. I suspect the majority of e-bikers you encounter are not "trained" cyclists. Cycling co-opts a number of pathways we use for walking so people who are untrained typically cycle like they would walk, where a casual pace translates to a cadence of somewhere around 50-60 RPM.

That said, mechanically and metabolically a lower cadence may actually be optimal for e-bikes. The assistance provided by the motor means your physical effort tends to be less. Studies have shown lower cadences (i.e., < 90 RPM) can be energetically optimal for lower efforts and longer duration activities. Higher cadences tend to be associated with harder efforts, especially in trained cyclists. Furthermore, people also have a tendency to self select the most the energetically optimal cadences, especially for longer duration activities. For what they are doing, a slower cadence may be sensible.

Answer 3

Personally it's because I'm using my ebike to get to work, wearing work clothes (which restrict my pedalling) and not wanting to get too sweaty. If I were just out for a ride I'd pedal faster.

Answer 4

For me, as an occassional ebike rider, it feels I get kind of better connection to the bike when pedaling at lower cadence, but higher force.

Because the electric assist otherwise reduces the needed force, it can feel like eternal downhill and it gets harder to sense your speed. But when I switch to higher gear so that I need to push harder on the pedals for a given power output it feels more like normal biking. I tend to do the same when going downhill on a regular bike also, even though I could as easily just not pedal at all.

Answer 5

It could be that all they are doing is rotating the pedals - not because they have to input any force to make the bike go but because the motor will not run with receiving a continuous signal from a hall-effect switch coupled to the pedals.

Thus the motor is enough to move the rider alone, but unless the rider is also rotating the pedals a cadence sensor as "safety feature", legislated in some areas, will detect that the rider is no longer rotating the pedals and will cut off the motor.

This is not a torque sensor, a much more expensive device.

Answer 6

I am a representative of "they", the slow pedaling e bike riders. Following a severe illness I am left weak as a baby. I have insufficient strength to pedal a standard bike, I need PAS (Pedal Assistance). Indeed after more than a years practice I rarely leave the turbo (max assist) mode.

Overall gearing is 1.08-1 in full underdrive. (42/22 x 0.5). My Elemnt records cadence to my phone and displays cadence in real time. Up a steep hill cadence may be as low as 35 RPM with about 65 RPM down hill. Any more than that and I collapse at the roadside panting and pissing. However the bike is designed for the fit too and will respond to whoever is capable of asking for it up to a cadence of 120 RPM so I suggest all the slow pedaling riders fit the category, unfit disabled and aged. Watch the young sporty lads and lasses racing e bikes, they are not us, pedal like billio.

Answer 7

The riders are pedaling only for the electric motor to kick in, not for creating leg power. For this they pedal as slow as they possibly can.

The main reason for the bike to work this way is a legislative one: it is a "power assist" bike not a scooter. Effectively most ppl use it as a scooter, some even install a throttle handle to override the pedaling mechanism.

Answer 8

I tested ebike today. I'm used to full-carbon race bike and ride daily for commute + hobby. i'm used to ride at 90+ RPM and i'm very happy with this cadence.

2 ebike : an low-end urban ebike, a mid/high-range mountain bike.

I tested the urban ebike first at my usual RPM. a few later after startup i was at 30+km/h (huh?), way above the 25km/h assist limit. i mostly wanted to play with how it handle at low assist, for endurance purpose.

Then i played with the MTB in "i'm super lazy mode" with the ridiculously high torque of the bosh performance CX.

It turn out immediately dropped my RPM to less than 60.

Simply because pedalling at high speed, even with 0 resistance (eg : freewheel or descent) IS work. 90+ is work for moderately trained cyclist, and impossible to untrained people sitting in front of a computer all day long. (i know i couldn't do it, 75rpm was my bested painful maximum for some time).

we ride at 90+ because it's more efficient to have high-speed low-torque than the opposite. And if you care aboute aerodynamic it's even more difficult to put high torque in crouched position.

But with ebike, you don't care about your muscle torque and don't care about efficiency if you just commute 10km on a bike that have 80+km battery. So.. max assist, no leg work, and not a care in the world about sucking up your battery at crazy rate.

Therefore : low rpm = less work (as long as you don't care about torque, which is the case on ebike at max assist)

offtopic PS : my tiny experience shown that the lowest assist mode on a heavy eMTB is pretty much the same thing as riding a lightweight carbon race bike. (on flat road, i didn't have any hill close enough)

Answer 9

My cadence on a road bike is usually between 90/min and 105/min. That is when I put about 200 W of power through the cranks. However, when I nearly coast my cadence goes down. There is no point in spinning rapidly when I do not work.

Over the course of the last two years I have ridden e-bikes on a few occasions. I am in Europe where a limiter kicks in at 25 km/h. With the electric assist I get to that speed without exerting myself at all. Now the same thing applies as when coasting on a regular bike. Namely, I pedal slowly in a low gear:

If I were to increase cadence by shifting down I would spin my pedals almost without resistance. This is uncomfortable.

Going over 25 km/h the motor assist would drop and I have to push pretty hard to go just slightly faster. The situation (family ride) never suited going that fast. It is also not all that fun on such an upright bike. Lastly, I took the e-bike because I did not want to get sweaty.

In summary: There is no reward for spinning faster in a high gear since the electric assist will drop out. Spinning fast in a low gear does not provide enough resistance to be comfortable.

Answer 10

Most people that I see on e-bikes are not 22 year old athletes wearing a yellow shirt. They're 45-75 years olds and just want to move their legs a bit (but not too much, to be honest) and be out in nature.
Or, as it happens, they're bankers in suits cycling to Bankfurt, which except during the heaviest rain and hailstorms seems to be a lot more appealing than driving with a car, given the traffic and parking situation.

A not-e-bike allows you to cycle with low cadence, too (assuming a bike with gear shift, which is de facto "normal").
But why don't people do that? Well because of the lever principle, and because of the power formula. You can gain the same speed by treading harder but slower, or by treading faster and more comfortably. Similar for power, you can just interchange speed and force (torque in this case). Tread harder or faster, same thing. Absolutely no difference.

So there's no real reason? Yes, except...

Except muscles don't care about your pretty laws of physics. Muscles don't like going out of their comfort zone too much. They will rapidly tell you by generating pain instead of power (pain persisting for days if you do it too long), and outside their comfort zone power output will overall be a lot worse. Incidentially, many machines (e.g. combustion motors) do not behave a lot differently. Electric motors are really a super rare exception because they operate in "don't care" mode at virtually every speed, and with ridiculously high torque all through.

Higher cadence means not only better (much better) power efficiency, but more importantly there's less torque (i.e. less muscle force) needed, which means more comfort, less pain and sweat, less "sheesh, I'm going to die", and less inability to walk during the next two days.

That's why you cycle at 60-70 rpm (or 90+ if you are young or sportive) rather than 15-30 rpm with a conventional bike.

With an e-bike, you can as well tread slower, which is less exertive. Let the electric motor help a little, why not (that's why you bought it). You do not even need to breathe noticeably faster. Which is nice if you like having a conversation with your partner.

Answer 11

One aspect not mentioned yet: With normal bikes cadence increases with speed in order to limit the force needed to sustain the speed. The wind resistance which must be overcome grows quickly with the speed, and e-bikers typically travel at speeds which would force an unassisted cyclist to increase their cadence because the force they can sustain has hit a ceiling. (This is the reason why a car typically does not reach its maximum speed in the highest gear -- too much force/torque needed.) With an e-bike the force comes from the motor, so a more comfortable and economical lower cadence can be maintained. Conventional biking at e-biking speeds at a low cadence would be hard on the muscles and knees.

Answer 12

High cadence is maximizing power output for trained bicyclists. Why would those be riding an E-bike?

A similar divergence is that high cadence, particularly when combined with sweat, stresses trouser legs which will get bulgy a lot sooner (and the seat area is also getting additional stress). That's one reason trained bicyclists prefer wearing biking clothes and having the work clothes stowed at work or in sidebags.

I went through a whole lot more trousers when using jeans rather than biking clothes everywhere. E-bike users tend not to wear special clothing: getting all sweaty is not what the bike is supposed to be for: rather you use it to arrive in presentable shape without significant adjustments.

A basic point of using an E-bike is putting less energy in yourself than you need for biking. Theoretically, you could just use it to buffer energy for the worst passages, but in practice they are charged externally.

Answer 13

We just like riding in the state of mindfulness. We find our joy is first in the journey, and then the destination.