Shifting a Class II - Mid-Drive

[Imchud]

A few weeks ago I recently purchased a Dost Kope 750 Mid-Drive (class II), I also own a Magnum Metro 750 Hub-Drive (Class II). The main reason for the new purchase was that I wanted a bike with more push or torque. I find the way they ride and handle are really two totally different ways, at least that has been my experience so far. I've owned the Hub-Drive for almost two years, and am so used to the way it handles that when I got the Mid-Drive I was trying to make it handle like the Hub, which is a mistake. My main obstacle with the Mid-Drive so far has been with hills and inclines, I am trying to figure out the best way or method when approaching a hill, to shift gears, and when to increase the PSA levels.

With the Hub, I would (depending on the incline or hill) usually pick the PSA level - let's say #4, Then as the hill got harder I would compensate and start to drop gears. But on the Mid, I am finding, since it has a lot more torque, I don't start to change PSA levels until I am into the hill, and as I do I find it necessary to upshift and/or downshift to make the hill and I seem to start and lose a little momentum as I go.

So, my question is... how do you, or what do you find the most effective way to shift or handle a Mid-Drive "Cadence" system? I am sure i need practice, but your help would be appreciated,

thanks.

 

[fooferdoggie]

I tend to push a bit harder then shift then I dont lose anything. I also keep track of my caddice and shift to keep it around 80 rpms.

 

[gromike]

Plan ahead, and do relaxed shifts. That means slowly turn the crank while shifting up a cog or two until you catch the gear. For me, with no shift sensor, it can be a bit of shock load on the drive train. With a hub drive you just shift like it's a regular bike.








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[m@Robertson]

I live where there are a lot of extremely steep hills so I deal with this sort of thing daily.

Its a pretty simple rule: Always shift in advance of the hill. Never ever let the motor bog. If it bogs that means you have greatly increased stress on the drivetrain. When doing your next shift and regardless of whether you have an IGH or a gear sensor, that is never good for the chain, or in the case of an IGH, for the long life of the hub's internals. Secondarily, all mid drives need to keep the motor rpms up high. If the current flowing in doesn't contribute to forward motion, it goes instead to generating heat which is a bad thing for the motor and its internals.

So, you shift in advance of the hill. This puts you into a lower gear than you need at the very base of the hill. So you do it *just* before, and you live with a small ability to spin the crankarms faster than you like for a short distance. As you lose forward momentum, ramp up the assist until you reach an equilibrium point of good assist, cadence and effort. When your hill becomes less steep, you ramp the assist back down a notch or three so you keep good effort on the pedals and cadence, when it steepens again adjust your assist level up and so on. Let speed take care of itself (i.e. don't worry about slowing down) while you master this technique. Focus on comfortable cadence and effort levels.

To repeat: You NEVER shift on the hill under load. It won't break the bike doing it once. Or twice or thrice. But over time you are wearing things harder than needed. Even with an IGH in the mix. Many IGH's die early deaths on DIY mid drive builds so they are by no means invincible.

Here read this. Its geared more towards higher powered mid drives with derailleurs but all of the rules and techniques described apply to any mid drive.

How To Ride a Mid Drive Ebike Without Breaking It

If you can ride a bicycle you already know how to ride a hub drive ebike. Not so a mid drive. Particularly a powerful one that can tear your chain apart. Fear not. The rules are simple.

talesontwowheels.com

And this discusses shifting specifically. Not for your motor but again this is the absolute safest way to do shifts with a powered drivetrain, regardless of IGH/derailleur. The stutter-step method is ingrained into my riding behavior and I do it unconsciously.

BBS02 and BBSHD: Do I want a gear sensor?

This is a common question on BBSHD and BBS02 motors, so I thought I would write up a quick post and describe what can be done, and what I do.

talesontwowheels.com

 

[JRA]

It really isn't any different than riding any bike with gears, e or non. All good suggestions above.

 

[Jeremy McCreary]

I know that the OP is asking about mid-drive shifting technique, but for those with a hub-drive with a derailleur and throttle...

The goal in letting up on the pedals during uphill downshifts is simply to reduce chain tension while the derailleur forces the chain to climb onto a larger cassette cog. You can accomplish the same thing with a 1-2 second blip of the throttle without letting up.

I find that I lose less speed on uphill downshifts this way.

This does not apply to mid-drives!

 

[PedalUma]

Yes, just ride it like a road bike or a sports car. Back off on pressure when down shifting in anticipation and rev up before up shifting.

 

[Rome]

I don't know what PSA is. I have Brose and Bafang ultra, similarly geared 11 speed 38 t chain ring. Shifting technique is different from each motor. Bafang with shift sensor and throttle it's easy to find the sweet spot when riding a long incline I use throttle to gain speed shift to higher gear , smaller gear that is to keep my momentum going.
Brose on the other hand not equipped with shift sensor you can forget up shifts in the middle of a climb. I just find that sweet spot which is 4th smallest gear to maintain speed usually 10-15 mph 80 rpm when I begin to get winded I shift to 5th smallest gear.
My advice is get familiar with the hills, inclines and declines in your riding range and find out for yourself where your sweet spot is. You might break chain or cassette but consider it normal wear and tear.

 

[Imchud]

I live where there are a lot of extremely steep hills so I deal with this sort of thing daily.

Its a pretty simple rule: Always shift in advance of the hill. Never ever let the motor bog. If it bogs that means you have greatly increased stress on the drivetrain. When doing your next shift and regardless of whether you have an IGH or a gear sensor, that is never good for the chain, or in the case of an IGH, for the long life of the hub's internals. Secondarily, all mid drives need to keep the motor rpms up high. If the current flowing in doesn't contribute to forward motion, it goes instead to generating heat which is a bad thing for the motor and its internals.

So, you shift in advance of the hill. This puts you into a lower gear than you need at the very base of the hill. So you do it *just* before, and you live with a small ability to spin the crankarms faster than you like for a short distance. As you lose forward momentum, ramp up the assist until you reach an equilibrium point of good assist, cadence and effort. When your hill becomes less steep, you ramp the assist back down a notch or three so you keep good effort on the pedals and cadence, when it steepens again adjust your assist level up and so on. Let speed take care of itself (i.e. don't worry about slowing down) while you master this technique. Focus on comfortable cadence and effort levels.

To repeat: You NEVER shift on the hill under load. It won't break the bike doing it once. Or twice or thrice. But over time you are wearing things harder than needed. Even with an IGH in the mix. Many IGH's die early deaths on DIY mid drive builds so they are by no means invincible.

Here read this. Its geared more towards higher powered mid drives with derailleurs but all of the rules and techniques described apply to any mid drive.

How To Ride a Mid Drive Ebike Without Breaking It

If you can ride a bicycle you already know how to ride a hub drive ebike. Not so a mid drive. Particularly a powerful one that can tear your chain apart. Fear not. The rules are simple.

talesontwowheels.com

And this discusses shifting specifically. Not for your motor but again this is the absolute safest way to do shifts with a powered drivetrain, regardless of IGH/derailleur. The stutter-step method is ingrained into my riding behavior and I do it unconsciously.

BBS02 and BBSHD: Do I want a gear sensor?

This is a common question on BBSHD and BBS02 motors, so I thought I would write up a quick post and describe what can be done, and what I do.

talesontwowheels.com

This is some great information to have, loved the articles you linked me to, so thank you for that. So, after reading all of this, I have a few more questions that come to mind. You mention NOT to shift under load, and that makes perfect sense. But if you still find you need a lower gear, can you "downshift" while climbing, or should not shift in either direction at all? Also, I am assuming you can still adjust the PAS levels on the fly, correct?

 

[Catalyzt]

This is some great information to have, loved the articles you linked me to, so thank you for that. So, after reading all of this, I have a few more questions that come to mind. You mention NOT to shift under load, and that makes perfect sense. But if you still find you need a lower gear, can you "downshift" while climbing, or should not shift in either direction at all? Also, I am assuming you can still adjust the PAS levels on the fly, correct?

My experience is with torque sensing mid drives, but I've found that I can downshift on hills... just not under load, and I always try to shift a little sooner than I 'need' to.

Thus, before getting to the hill, I downshift to whatever gear seems one or two gears too low-- in advance.

Once I'm on the hill and ascending, I continue downshifting, but only while "ghost pedaling" briefly-- e.g., pedaling not quite fast enough to keep up with the wheels and motor, losing just a little momentum for a second. The telltale is, if I hear a loud CLANK or chiming sound from the gears, and I feel a lot of feedback from the drivetrain, I know I did it wrong.

If I hear just a little click, and there's no feedback from the pedals, I know I did it right.

Is that what everyone else is saying, or am doing something different?

 

[keithj69]

As others have mentioned, judge your shifts ahead of time. I'll add, as a habit, learn regardless of riding how to let off the pedals then shift. As long as you slow the pedaling where you have no load on the crank/gears, then shift while still pedaling, it will become natural. Try not to lose too much in the cadence you have going. You can feasible slow your pedal enough to shift and still maintain the cadence rpm of the motor. It takes practice. Just don't shift under load. You will hear and feel it.

 

[fooferdoggie]

one trick I have going up really steep hills 18% grades and worse. I peddle and go as fast as is practical and just as I start on the hill I shift to the largest cog and cost per peddle normally till I slow enough to to be using that gear. Because I know I will need that cog it makes it easy. you can do the same on other hills if you know what works for you well. this really helps on the tandem since it is harder for both of us to let up on peddling.

 

[Imchud]

Hahaha... sorry guys... I just realized In my original post I referred to the "Pedal Assist System" (PAS) as "PSA" which actually refers to the levels in your Prostrate... so nothing to do with riding an e-bike.

 

[Jeremy McCreary]

Hahaha... sorry guys... I just realized In my original post I referred to the "Pedal Assist System" (PAS) as "PSA" which actually refers to the levels in your Prostrate... so nothing to do with riding an e-bike.

Disagree, your prostate has everything to do with what gives out first on an ebike ride — you battery, your legs, your butt, or your bladder capacity.

 

[m@Robertson]

...if you still find you need a lower gear, can you "downshift" while climbing, or should not shift in either direction at all?

Your bike will hate you a lot less if you do your shifting all in advance of the hill and never shift in either direction once on it. Something to bear in mind is you have a motor now so the need to row thru the gears to get just the right ratio while in a climb is a lot less than on an analog bike. For example, with motor assist now vs. days of yore I can just change my effort level (more effort or less effort) and maintain cadence for a short stretch thanks to a changed assist level. That is just not possible on a purely human-powered bike. If the hill steepens I would have to downshift a bike. But on an ebike I can go from '3' to '4' and change nothing else. And if it levels off a tad maybe I drop back to '2'.

@Catalyzt and a couple of others mentioned overdoing it initially. Shift to a lower gear than you think you will need. I do this as well. When I said to fuggeddaboud speed this is what I was doing a poor job of articulating: Let the speed drop waaaay down by going into a too-high gear. You end up going slowly but easily (so much so you may need to back way off on the assist level). Go up the same hill a couple three times and you'll know in advance where you want your gear to be, but during your initial uncertainty phase you will err on the safe side. Erring on the other side and being in a too-high gear is a lot messier. What you want is a gear that is mechanically able to easily handle the hill, so all you have to do from there is click PAS levels up or down.

As others have mentioned there are ways to further fudge this, like with a momentary burst of effort to gain enough speed you can lift your pedal effort and shift before you run out of momentum. The easy, just-learning way is to shift at the bottom just before the hill. Get fancy later.

Also, I am assuming you can still adjust the PAS levels on the fly, correct?

Yeah this is a tool that is the proverbial game changer.

I know that the OP is asking about mid-drive shifting technique, but for those with a hub-drive with a derailleur and throttle...

What I found is that, since the hub motor is powering the bike thru the axle/hub and it couldn't care less about the drivetrain (and is in fact disconnected from it due to an internal clutch) you can shift to your heart's content with no restrictions of any kind. Do your worst. If anything the hub motor in the mix makes shifting less consequential to any sort of potential drivetrain stress.

 

[Jeremy McCreary]

What I found is that, since the hub motor is powering the bike thru the axle/hub and it couldn't care less about the drivetrain (and is in fact disconnected from it due to an internal clutch) you can shift to your heart's content with no restrictions of any kind. Do your worst. If anything the hub motor in the mix makes shifting less consequential to any sort of potential drivetrain stress.

On modest grades, I agree. But on steep grades — say, 10% and up — my experience is a little different. If I don't ease up on chain tension one way or another when downshifting on such pitches on my hub-drive, I hear complaints from the drivetrain behind me. Otherwise, my shifts are very quiet.

Those clicks and clacks may be harmless, but I'd rather not hear them.

 

[Kayakguy]

I don't know what PSA is. I have Brose and Bafang ultra, similarly geared 11 speed 38 t chain ring. Shifting technique is different from each motor. Bafang with shift sensor and throttle it's easy to find the sweet spot when riding a long incline I use throttle to gain speed shift to higher gear , smaller gear that is to keep my momentum going.
Brose on the other hand not equipped with shift sensor you can forget up shifts in the middle of a climb. I just find that sweet spot which is 4th smallest gear to maintain speed usually 10-15 mph 80 rpm when I begin to get winded I shift to 5th smallest gear.
My advice is get familiar with the hills, inclines and declines in your riding range and find out for yourself where your sweet spot is. You might break chain or cassette but consider it normal wear and tear.

PSA is Prostate Specific Antigen. Many of us older guys are familiar with it. PAS refers to pedal assist system. The male prostate is an example of unintelligent design. One of evolutions little screw ups that employed existing organs in a makeshift manner. Just as your bad back is the penalty for upright stance and walking.

 

[gromike]

Evolution never planned on a 70+ year-old bicycle rider. YMMV.

 

[PedalUma]

Is that what everyone else is saying

You are doing it right.
Just as a note: Remember that cassettes have ramps to help achieve a lower gear. These become further apart like the cross section of a conch shell as the gear becomes lower and larger around.

 

[Jeremy McCreary]

Remember that cassettes have ramps to help achieve a lower gear. These become further apart like the cross section of a conch shell as the gear becomes lower and larger around.

Never thought about that part of downshifting mechanics! To make matters worse, in a typical cassette, cog diameters increase exponentially as you go to lower and lower gears — meaning that the chain has to jump higher and higher with each successive downshift.

No wonder downshifts under load go better at reduced chain tension.