Mid-drive vs hub motor: Experiences

Stefan Mikes

Well-Known Member
Now, in the defence of the geared hub motor e-bikes:

Once, I broke the chain on my hub-motor bike (because of an ill-adjusted derailleur). At that time I even didn't know what the chain tool was :D I thought:

-- If there is a pedalling sensor somewhere in the crank, I might use pedals as if they were a throttle!

And it was. I removed the broken chain, got me onto the saddle and started pedalling vigorously. It worked. The pedal assist was activated and the hub motor drove my e-bike at low but manageable speed. It was enough to get me couple of kilometers to the venue where I was expected to hold a conference (luckily that was a preparation day before the event). Then I took a commuter train back to my town and I again pedalled the last kilometre back home.

Something you cannot do with a mid-drive motor.
 

6zfshdb

Well-Known Member
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.
There are many opinions on the subject and I tend to agree with Thomas. Many riders have difficulty pedaling, especially during start up, and without throttle assist, would ride little or not at all. For these folks, there would be no health benefit whatsoever.

Just because a bike has a throttle doesn't mean you have to use it. I use mine sparingly but I wouldn't own a bike without one. I occasionally use mine to get started particularly if I forget to downshift before stopping. My bike has an annoying delay before the torque sensor kicks in which makes initial pedaling very difficult.

For me, the throttle is a form of insurance which improves my riding enjoyment. I no longer fear I'll get stranded if I have a joint issue when riding some remote trail. In a way, it's similar to the emergency brake on my car. I rarely use it but I'm glad it's there.
 

Thomas Jaszewski

Well-Known Member
It becomes personal, Thomas.
Yes, I thought it did when you wrote in the judgment of throttle use,"Why not to buy an electric motorbike or drive a car." I gave up motorcycles when I could no longer manage the weight. My Vespa did nearly 100miles on a gallon of gas. Electric would be nice if I could manage the weight, AND the price...
 
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Thomas Jaszewski

Well-Known Member
The only hub drive I own that becomes anemic in a headwind is my 350W 36V MXUS GD. My MAC GD, and MXUS 1000W are just as capable as my mid drives. actually less fussy about how they are run as well. The MAC 10T is a pretty good climber too. I like that I can run 36V, 48V, and 52V batteries without any reprogramming my Grin controller. Mind you, no real hills to ride up other than county highways that are anything but bicycle-friendly. So I stay well away.
 

stanmiller

Member
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...
This is my experience as well. With the Bluenergy/Greenergy kit controller, the PAS setting acts as a pedal activated throttle with a speed cap.

BAFANG Rear Wheel 500W 48V Hub Motor with SW102 Display

Now, I rode both my bikes without power. The geared hub drive e-bike just behaves as a very heavy acoustic bike, the freewheeling is working properly.
Indeed. For exercise (and to generate body-heat in these winter months), at times I ride the bike powerless.

I went with a hub motor conversion to maintain the original setup. The factory 3x8 drive-train is geared like an 18 wheeler. On the flats you barely notice the extra weight of the motor and battery. And on hills, the Mongoose Envoy is a real climber though each stroke of the pedal might not get you too far.

44748

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Stefan Mikes

Well-Known Member
I meant "becoming personal" @Thomas Jaszewski when you meant "stupid European rules". So stupid that there are ten times e-bikes in Europe than are in North America. I don't want to go personal though.
 

AHicks

Well-Known Member
Mid motors come in either single-clutch or double-clutch flavor. As far as I can understand, the single clutch disconnects the crank in the way that allows coasting. If the system is double-clutch, the second clutch disconnects the crank from the motor completely, so you can ride without any pedalling assistance.

Now, Brose and Specialized motors as well as some Yamaha motors are double-clutch type. Shimano STEPS is single clutch. Not sure about Bosch Gen 4 but all older Bosch motors are single clutch. How can you tell? Look at the chain-ring. If the chainring is small, e.g. 15-18t, the motor would be single clutch type. If the chainring is 38-48t, that would be the double-clutch kind. The point is, in case the chainring is small, the crank is connected to the motor via internal gears. In case power is lost, you have to pedal through the internal motor gears which creates significant resistance. In case of double clutch motors, you just drive the rear wheel by pedalling, as if it were an acoustic bike.

Now, I rode both my bikes without power. The geared hub drive e-bike just behaves as a very heavy acoustic bike, the freewheeling is working properly. More interesting is the behaviour of the double-clutch mid-drive motor bike. I lost the power on my Vado 5 twice: Once it was a stuck display; the second time I simply run out of the battery. In both cases I could ride only pedalling. My speed upwind was some 12 km/h and with no wind some 18 km/h -- something I could achieve on an acoustic bike -- and I rode for 15 km without power. I can bet that would be much harder on a Bosch or Shimano system.

Direct Drive hub motors are probably very resistant un-powered but I have no experience with these.

The "secret sauce" for Brose/Specialized and some Yamaha motors is the double clutch.
Just to confirm, the unpowered DD hub does pedal with a slight amount of resistance. There is no clutch to uncouple the motor from the drive system. The upside would be that there is regen available for those interested.
 

AHicks

Well-Known Member
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.
My guess. The reason for the stalled condition is about a relatively low powered motor (250w), and the difference in the available gear ratios. The gear driven hub w/250w motor will have something like a 5:1 gear reduction. The 250w mid drive has several gear ratios available, and depending on which one you use, may give the mid drive a serious advantage due to the gearing available. In 1st (granny) gear for instance, the mid drive will be very difficult to stall to my way of thinking. -Al
 

Stefan Mikes

Well-Known Member
My guess. The reason for the stalled condition is about a relatively low powered motor (250w), and the difference in the available gear ratios. The gear driven hub w/250w motor will have something like a 5:1 gear reduction. The 250w mid drive has several gear ratios available, and depending on which one you use, may give the mid drive a serious advantage due to the gearing available. In 1st (granny) gear for instance, the mid drive will be very difficult to stall to my way of thinking. -Al
It makes sense, thank you!
 

AHicks

Well-Known Member
A related question on mid vs hub...

The most common hub motors, like Bafang, freewheel when PAS is off, or the battery is dead.

I know there's other factors (bike weight etc) to take into account, but do all mid-drives add the same amount of resistance when PAS is off (or the battery is dead) or is there secret sauce that Specialized has compared to Bafang (for example) or does Bosch have less resistance than others (etc)?

I'm currently in the very early stages of considering adding a second e-bike, and was curious to hear from those who've ridden both on a regular basis.
Again, we don't know if your question is regarding gear driven hubs, direct drive hubs, or both! They are WAY different, especially as applies to this question.

Also, I think there will be quite a few who disagree with the "most common" statement. I've never seen actual data, but my experience would indicate there are easily as many direct drive rear hubs in use as there are gear driven.

I'll stop there as I think Stefan Mikes did a nice job answering the rest of the question. -Al
 

hewstigator

New Member
after wrestling with removing and re-mounting the rear wheel on my direct drive hub last night, i would have to say a significant benefit to mid-drives (in addition to the many benefits mentioned here) is simplicity in wheel changes. i always seem to have trouble lining up things right even though i'm only running 1.75" tires
 

AHicks

Well-Known Member
Not to discredit your thought, but I can assure you that it will get easier after you've done it a few times.
 

hewstigator

New Member
i hope so!! even on my lighter geared hub bike i always seem to run into something screwy - after swapping to my winter spikes on that bike, i introduced air into my brake system from having the bike flipped wheels-up... so i bled the system, only to get mineral oil on both front and rear brake pads, AUGH
 

Browneye

Well-Known Member
There are so many misconceptions regarding PAS effectiveness. Some system do actually provide the ability to get exercise or clown pedaling. This regarding torque sensing bottom brackets.


Torque Sensors
Example Bottom Bracket Torque Sensors

>snip
Would any of these plug into my controller in place of the existing crank/pedal pas sensor?

Our crank pas sensor provides on/off switch for the geared hub drive (bafang) - the pas level on the controller sets the max speed.
I might be willing to try one of these torque-sensors if the price of admission isn't too steep. Wife uses her throttle very little, but also discovered how handy it is for jump-starts in top gear. Otherwise, I guess it's called 'clown-pedaling' - just enough crank motion to keep the pas engaged and the hub driving. Would be nice to have a little more user-integration here.

Comparing our two bikes - IMO the Giant provides a much much nicer assist integration than the hub conversion. As far as speed and power, they're similar, but the mid-drive is 250w/36v and the geared hub is 500w/48v. One would think there would me more difference. Plus, with proper gear selection, the mid-drive is a much better climber.
 
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harryS

Well-Known Member
Would any of these plug into my controller in place of the existing crank/pedal pas sensor?
You need a controller that can recognize the signal and use it, Or you can do something with the Grin hardware to make that happen. I don't see the need to spend $200-300 (aftermarket) to have purity in the pedals. It's less if you design it in from the start like Juiced.

This is just my interpretation, but I've been followng Bromptom's efforts on their first e-bike, a front drive folding bike with a cadence sensor. I believe they're trying to make it idiot proof. One goof on a cadence sensor is when we lift the rear wheels to align the pedals for a flying mount start. If the motor starts, no big deal with wheels off the ground. WIth a front drive, the bike takes off. So Bromptom must have trying to program in the situation with a stopped motor and sudden rapid turn of the pedals. Their first release had a lot of customers complaining about bikes that were flaky when starting off. Points out the difficulty of designing a robust pedal system. Meanwhile, this oops doesn't exist with a T/S system, but I have read about people resting their feet on the pedal too hard at a stop, and the T/S bikes tries to start up.