Mid-drive vs hub motor: Experiences

[Stefan Mikes]

I own two e-bikes, one with a hub motor and the other with a mid-drive one. When I was riding either of them at relatively warm weather, gentle breezes (and the terrain here is flat), I felt no real difference between them. The things have changed with the season of stiff winds interrupted with squalls.

Depending on the assistance level, the hub motor provides some support. You need to follow what the motor is doing by pedalling at the right gear until some resistance from bike can be felt. The controller also reads your cadence and adjusts the power accordingly until the equilibrium is achieved. It feels as if you needed to follow the motor with your pedalling. Now, if an adverse squall hits you, the bike slows down. As you instinctively maintain the equilibrium of forces, you pedal at slower cadence. Then, the controller thinks "Oh, this guy wants to ride slower!" The power to the motor is reduced and you are stalling. Unless you shift down and increase the cadence, so the controller can pump some more juice into the motor.

It is different with the mid-drive motor. It is the motor that follows your pedalling, and the torque sensor is there, in addition to the cadence sensor. In the case of a squall, you instinctively stamp on pedals harder. Instantly, the controller gives motor more power. So your bike won't slow down but would rather pierce through the wind as a hot rod cuts through thin ice.

It is similar while climbing. Provided you are in more or less proper gear, the mid-drive motor e-bike can climb at constant speed while the speed of the hub motor bike gradually drops down until the equilibrium is reached.

My observation is two different bikes, either with different motor type use energy differently on the same routes under the same weather conditions. The simplest explanation would be it costs you the battery energy to ride at constant speed regardless varying resistances during the trip. Hub drive motor does not support you as efficiently but uses less energy overall.

On my winter rides, my mid-drive e-bike has the range of approximately 80% of what the hub motor e-bike can provide, with similar battery capacity.

Your observations?

 

[opimax]

To compare apples to apples need more info. My 1st thought is is your hub drive is a cadence sensor and your would do better with a torque sensor, it is more responsive. What model bikes ? Is power similar ? are you in the correct gear For what you are doing (going up hill) ?

Really need more info...

 

[AHicks]

I do love reading rider impressions!

My first question, as always when a hub drive is being discussed, is are we talking about a direct drive rear hub, or a gear driven rear hub?

Too, the controller logic, from what I have read about from quite a few riders impressions, how it reacts to different inputs, is not the same on all bikes. I've seen comments from many different riders whose impressions on the difference from one PAS level to the next, and it seems like they're all over the ball park. Is it just me? Probably a question best asked as a new topic. On my own bike (a gear driven rear hub type), the PAS levels seem pretty intuitive. You select the level of assist you're after (using PAS level), and that's what you get. Cadence speed has no effect on the assist level. You can pedal slow, or fast, and get the same amount of assist.

 

[Stefan Mikes]

a gear driven rear hub?

A gear driven rear hub it is.

Cadence speed has no effect on the assist level. You can pedal slow, or fast, and get the same amount of assist.

Are you sure? My ebike has a cadence sensor and I can feel the effect of different cadences. I could be wrong.

 

[AHicks]

Are you sure? My ebike has a cadence sensor and I can feel the effect of different cadences. I could be wrong.

Yup, pretty sure! Easily confirmed as the wattage the motor is consuming at any given time is supplied as a direct read out on the display.

Controller and display are by KT systems. Pretty popular on the aftermarket, but very few using them on production bikes.

As mentioned, I think there is likely a wide variety of controller software programming in use. It's the only reason I can think of for some of the differences among so many rider impressions. Maybe due to the fact that the e-bike industry is still making rapid advancements and constantly evolving. What worked well a few years ago may be outdated today? -Al

 

[JRA]

"Depending on the assistance level, the hub motor provides some support. You need to follow what the motor is doing by pedalling at the right gear until some resistance from bike can be felt. The controller also reads your cadence and adjusts the power accordingly until the equilibrium is achieved. It feels as if you needed to follow the motor with your pedalling. Now, if an adverse squall hits you, the bike slows down. As you instinctively maintain the equilibrium of forces, you pedal at slower cadence. Then, the controller thinks "Oh, this guy wants to ride slower!" The power to the motor is reduced and you are stalling. Until you shift down and increase the cadence, so the controller can pump some more juice into the motor."

This is the exact reason that I prefer a front hub motor for road use with no PAS because I can set the watt level and then pedal as I naturally would within the range of gearing necessary to compliment it. I liken it to having an electric trolling motor on a row boat. Because the motor doesn't have any dead spots it deletes the ones that a rider with less than perfect "spin" deals with on a conventional road bike. My bikes are DD btw.

In my experience being able to accurately track/set the wattage output as Al suggests is key to managing the e power levels to your current riding experience and expectations.

For the lower and more variable cadence of MTB I much prefer a torque sensing mid drive. And while I have towed a few roadies in my day riding it between trailheads it doesn't feel like road biking but the fact that I have magic legs which is not bad but not as efficient and as mentioned above using more energy to do so.

 

[Marci jo]

Thanks Stefan Mikes.
Although I don’t have a hub motor ebike, I can attest to the effects of a strong head wind while riding a mid drive ebike. I find myself trying to hold my regular speed and of course the motor responds accordingly. Bye bye battery charge! It’s a great lesson in battery maintenance.

 

[Browneye]

I don't ride in squals. Problem solved.

Seriously, on our two, the Giant assist is much more integrated with the rider. But the Bafang hub keeps speed just fine. Both have excellent range, and are easy to ride, both are virtually silent. Both are very enjoyable.

For a new enthusiast trying to choose, I think either works well, but the hub-drive bikes seem to come in at a lower price point. If money isn't an issue I recommend they try both and decide what THEY like.

For eMTB, definitely mid-drive. Hands down. For a bike-trail cruiser either works well. I don't get involved with long distance daily commuting - that's a whole 'nother set of requirements.

 

[Stefan Mikes]

Seriously, on our two, the Giant assist is much more integrated with the rider. But the Bafang hub keeps speed just fine. Both have excellent range, and are easy to ride, both are virtually silent. Both are very enjoyable.

Same observation here as long the ride is on the flat and no strong headwinds.

For a new enthusiast trying to choose, I think either works well, but the hub-drive bikes seem to come in at a lower price point. If money isn't an issue I recommend they try both and decide what THEY like.

My hub motor e-bike price was the half of what I paid for the other one. Agreed.

For eMTB, definitely mid-drive. Hands down. For a bike-trail cruiser either works well. I don't get involved with long distance daily commuting - that's a whole 'nother set of requirements.

I'd like to hear a comment from a touring cyclist who carries camping equipment and has to climb long stretches on tarmac. Would the geared hub motor do at all?

As mentioned, I think there is likely a wide variety of controller software programming in use. It's the only reason I can think of for some of the differences among so many rider impressions. Maybe due to the fact that the e-bike industry is still making rapid advancements and constantly evolving.

It is not that I disagree. I don't know. It is apparent to me that when I'm hit by adverse squall, the hub motor suddenly loses power. Trying to guess the reason.

To compare apples to apples need more info. My 1st thought is is your hub drive is a cadence sensor and your would do better with a torque sensor, it is more responsive. What model bikes ? Is power similar ? are you in the correct gear For what you are doing (going up hill) ?

Sorry, @opimax, I missed your post. The make of Lovelec and the model name Diadem would tell you nothing. It is a hybrid bike with a 576 Wh 36V battery and a generic Chinese 250 W geared hub motor. The other bike is Specialized Turbo Vado 5.0 with 250 W motor and a 604 W battery.

Although I don’t have a hub motor ebike, I can attest to the effects of a strong head wind while riding a mid drive ebike.

@Marci jo: @Readytoride has described similar experiences with her Giant La Free and a Vado 3.0 of her friend recently.

 

[Ken M]

A gear driven rear hub it is.

Are you sure? My ebike has a cadence sensor and I can feel the effect of different cadences. I could be wrong.

There is this misconception that cadence PAS varies the power according to the cadence but the vast majority are just on/off switches for the power level setting. They could vary the assist provided but is the assumption that a faster cadence always means the rider wants more assist power a good assumption. In reality then you could just ride the bike in one gear and use cadence speed as your throttle (the old Izip Express allowed this but cadence was measured using a small motor driven by a belt from the crank to generate higher back emf voltage that was used as a throttle input).

There are "shortfalls" to crank torque based PASs as well. In reality some weak riders may not be able to put enough torque into the crank to ever get full assist power and they may actually need it more than a powerful rider than can easily max out the torque sensor. No one likes to talk about these things because in reality a throttle that simply allows the rider full control of the assist level is best. I understand it may not provide the true feel of a bike like a torque PAS but I simply prefer to control the assist level myself and not some program that a soda drinking fat code writer thought was best to embed into the controller firmware. I'm not going to get hammered by all those that love the riding experience of a torque PAS. I like them too but they have shortfalls (I can point some legit riding ones out but too long for now).

 

[hewstigator]

i see the same thing as ahicks is seeing - you pick a level of PAS and the motor gives that level of assist regardless of cadence but tapers off as you hit the target speed of that particular PAS setting. for me if i want to do any sort of pedalling i undershoot my target speed with PAS and then add as much pedalling as i care to, and i ride the same way on either my older surface 604 colt (the one with the older bb torque/cadence sensor) or my ebikeling traditional magnet wheel / hall sensor kit. the torque part of the colt's sensor seems to mildly moderate the level of assist but it is a pretty subtle effect so if you are not feeling very 'motivated' you can get away with providing almost no torque and it will still give you a lot of assist.

 

[Stefan Mikes]

No one likes to talk about these things because in reality a throttle that simply allows the rider full control of the assist level is best.

Using a throttle doesn't contribute to the rider's health condition. Why not to buy an electric motorbike or drive a car I'm an advocate of pedalling.

you pick a level of PAS and the motor gives that level of assist regardless of cadence but tapers off as you hit the target speed of that particular PAS setting.

I'm not sure if the speed really matters. I would rather agree with @AHicks and @Ken M that the hub motor is fed with constant power depending on the PAS level and the speed is the outcome of different resistances met on a ride. I can't still understand why the hub motor in my e-bike obviously "weakens" for a while when I'm stalled with a squall. I can hear and feel it even if the motor is almost noiseless.

 

[6zfshdb]

Although many of these hub vs mid drive observations are valid, it should be noted that performance varies widely from model to model. During my 9 month marathon test riding experience, I noticed a significant difference in performance between various mid drive bikes. The same was true, albeit to a lesser degree, for hub drives. Individual preference and riding style varies greatly among riders so one's point of view can be somewhat personal.

The one thing I learned from these test rides is mid drives are better, more efficient hill climbers than hub's.

 

[hewstigator]

well like ahicks mentioned the programming varies a lot so for example, on my colt, i could take the bafang programmer cable and change the settings so that each PAS level gives a certain amount of assistance without any speed restriction (which a decent number of people like to do), but by default each level has its own max speed where it stops assisting.

i might be in the minority, but i happen to like the speed limits because sometimes i get caught behind a cyclist in an area that would be too crowded to politely pass, and need to find a setting so that i don't have the annoyance of needing the PAS turning on and off to modulate speed.

 

[tomjasz]

I have MAC GD, MXUS GD, MXUS DD, BAFANG BBS01, had 3 BBSHD, and a TSDZ2. Each a very different bike. All have their place. Probably going to get a BBSHD again for those quick trips keeping pace in 30MPH traffic.

 

[tomjasz]

Using a throttle doesn't contribute to the rider's health condition. Why not to buy an electric motorbike or drive a car I'm an advocate of pedalling.

Really? And when you no longer have the leg strength or have a disability? You will quit riding? I pedal MOST of the time but with little or no resistance. My legs and back are trashed. Even clown pedaling gives a range of motion. Throttle means I can make far longer trips. Why an electric motorbike when a bicycle suits? All rhetorical, as I tire of these opinions by those able and not thinking about those less than able.

 

[Stefan Mikes]

I'm not able at all Thomas. I will pedal until I can. (My intermittent claudication makes walking as far as 100 yards a pain for me. Pedalling doesn't).
I respect needs of disabled people but don't call it cycling.

 

[tomjasz]

I'm not able at all Thomas. I will pedal until I can. (My intermittent claudication makes walking as far as 100 yards a pain for me. Pedalling doesn't).
I respect needs of disabled people but don't call it cycling.

Cycling, I ride my eBike and I cycle. Cycling with a throttle. It's a bicycle. It has functional pedals and by US statute it's a bicycle. Those silly EU rules are discriminative.

 

[Stefan Mikes]

It becomes personal, Thomas.

 

[Browneye]

We've covered more ground on the ebikes the past two months than we did on the pedal bikes for the past two years. Best invention ever!
I don't think ebikes would have come along without the latest battery technology. The old nickel-cadmium batts just would never have worked like these new packs.