Mid crank drive motor - what type of gears are best?

[Kelly P]

In my search for a folding ebike that I can wheel easily, I've been looking at Dahon conversions.
(Incase anyone hasn't read my other posts - My commute is 6 miles, I want a folder I can fold and then tilt on its wheels to roll - the Dahons do this. No public transport to go on, just want a folder so I can store it inside my home and office).

I have a couple of questions I wondered if I could get some advice on?

Question one....I'm looking at the mid drive motors, the options are Bafang or GSM (both 250w with built in controllers) - I've read on here about some issues with the GSM - do they still stand? The GSM option is around £100 less than the Bafang.

Question two....I have the option of either hub gears (3 or 7 gears, depending on the bike I choose) or 8 speed derailleur. I like the idea of hub gears but I'm aware I would need to slow/stop pedalling to change. The hub gears are more expensive. Apart from easy maintaince, less likely to get caught etc - is there any major benefits of hub gears, I.e do hub gears work better with a crank drive motor or does it not make any difference?

Thank you in advance

 

[trex]

for folding bikes, 3-speed hub gear is the best compromise.
The bugbear of crank driven systems is the chain and gears. You need to select the right gear and you don't want the chain to come off, ever.
I must say that I am much an aficionado of the Gtech way: no grease, no wires, nothing to adjust and easy to lift. My current CD bike has an SRAM 2-speed automatix which I find adequate for riding around in London. Totally noiseless and always in the 'right' gear.

 

[SteveRuss]

Question two....I have the option of either hub gears (3 or 7 gears, depending on the bike I choose) or 8 speed derailleur. I like the idea of hub gears but I'm aware I would need to slow/stop pedalling to change. The hub gears are more expensive. Apart from easy maintaince, les

Why do you think you have to slow or stop pedalling to change gears on a hub geared bike? My Alfine 8G is fantastic and has no such restrictions. The gear change on the fly is silent and smooth. If anything, the fact that you can change gear whilst not moving then simply pull away was the game changer for me. I wouldn't be without hub gears by choice now.

 

[trex]

On crank drive systems, you still need to cut power to the motor before you change gear. Hub gears don't make much noise during shifting even if the power is still on, but it's not good for them if you shift under load. On expensive CD bikes, sophisticated software and/or a gear sensor will do that automatically for you. Chinese CD kits don't come with gear sensor, you have to cut power manually, either by stopping your pedaling long enough before the gear change or blipping one of the brake levers a little bit to cut the power just before shifting. I like the Sram automatix for the reason that the shifting is by inertia, the box knows when it's the right time to shift avoiding accidental damage to the hub gear.

 

[SteveRuss]

On crank drive systems, you still need to cut power to the motor before you change gear. Hub gears don't make much noise during shifting even if the power is still on, but it's not good for them if you shift under load. On expensive CD bikes, sophisticated software and/or a gear sensor will do that automatically for you. Chinese CD kits don't come with gear sensor, you have to cut power manually, either by stopping your pedaling long enough before the gear change or blipping one of the brake levers a little bit to cut the power just before shifting. I like the Sram automatix for the reason that the shifting is by inertia, the box knows when it's the right time to shift avoiding accidental damage to the hub gear.

I suppose I kind of misread her comments

My Kalkhoff has a mechanical gear sensor and I think you can fit those to most of our bikes I believe. I would have thought that most of these kits would come with something similar no?

 

[trex]

you can buy a gear sensor for the 8-Fun BBS01 for about £50 (gearsensor.com), but it's easy to get used to changing gear on a Chinese kits.

 

[Kelly P]

Thank you - that really helps.

What is your opinion on deraileurs and crank drive motors?

And any ideas about Bafang vs GSM? Is it worth paying extra for Bafang?

 

[Artstu]

Thank you - that really helps.

What is your opinion on deraileurs and crank drive motors?

And any ideas about Bafang vs GSM? Is it worth paying extra for Bafang?

Unless they've made massive strides in the speed at which the power goes on and off I wouldn't touch one myself. and from Trex's comments above it doesn't look like they have.

If I still wanted one I'd say it was essential to try before buying to see if you could cope with the way they change gear.

Bosch, Yamaha, impulse and some other OE systems (not sure of the names?) are much better with instant on and off power which makes gear changing easier to master.

ETA, I imagine the gear change issues to be much easier to deal with in flatter areas, here in the south Pennines they just don't work well enough for me.

 

[SteveRuss]

Thank you - that really helps.

What is your opinion on deraileurs and crank drive motors?

And any ideas about Bafang vs GSM? Is it worth paying extra for Bafang?

I don't think there is a final conclusion on whether the GSM or Bafang mid-drives are better or worse than each other. I've read a lot of that thread on here and there appears no clear direction to take. Personally, I would spend the extra on the Bafang at this stage as it appears a much more tried and tested choice.

After owning an Alfine 8 hub gear system, I can think of no reason why I would want a derailleur based bicycle again. Other than cost but even then... Of course this is a personal choice but to me, it seems the best choice for people that don't want to constantly be cleaning and maintaining their derailleur's and rear cogs and just want to ride.

 

[Artstu]

After owning an Alfine 8 hub gear system, I can think of no reason why I would want a derailleur based bicycle again.

I imagine it would be very easy to break an Alfine hub with a Bafang CD motor, mess up the complex (brake dab to cut power) gear change and the hub isn't going to like it.

The power of an e-bike masks the less efficient hub gears slight drag, I'm happy with the hub gears on my e-bike, but I'd take a derailleur on a bike without a motor.

 

[SteveRuss]

I imagine it would be very easy to break an Alfine hub with a Bafang CD motor, mess up the complex (brake dab to cut power) gear change and the hub isn't going to like it.

The power of an e-bike masks the less efficient hub gears slight drag, I'm happy with the hub gears on my e-bike, but I'd take a derailleur on a bike without a motor.

Yep. I've never tried one off an pedelec myself. As mentioned, the gear based inline cutoff's are available for an extra £50 which I would definitely buy.

 

[Kelly P]

Thank you for your help.

I am looking at Dahon conversionbikes from CH White and Son....

OR.....

Buying a donar bike and kit... Anywhere you recommend CD kits that will fit a folder? (And also a company that will fit said kit).

Found this bike with automatic hub gears...
https://www.ebay.co.uk/ulk/itm/262365747883

 

[SteveRuss]

Found this bike with automatic hub gears...
https://www.ebay.co.uk/ulk/itm/262365747883

I'd be interested to know how much that bike ends up going for.

Just over 14kgs plus 6-7kg's for the motor battery combo and your in the 20's. That is pretty heavy for something you fold and carry. My Kalkhoff is around 24kgs all in and I struggle lifting it up the stairs to my house, although they are particularly steep

It could end up being a very nice custom folder though!!

 

[Artstu]

I have a Dahon Mu, I'm fairly sure it would not be easy to roll when folded. Perhaps it may just be the magnet that holds it together whilst folded that needs improving to hold it together better and stop the front wheel from angling away from straight, perhaps that's something that has been added on newer versions that allow them to be rolled?
Steve makes a good point about weight, even my standard Mu is difficult to carry and handle whilst folded.

 

[Kelly P]

This is my other (ready made) option:
http://foldingbike.biz/epages/7665e38c-067c-4fa0-9037-afac2266f927.sf/en_GB/?ObjectPath=/Shops/7665e38c-067c-4fa0-9037-afac2266f927/Products/DAHCURVED3ELECTR

 

[SteveRuss]

This is my other (ready made) option:
http://foldingbike.biz/epages/7665e38c-067c-4fa0-9037-afac2266f927.sf/en_GB/?ObjectPath=/Shops/7665e38c-067c-4fa0-9037-afac2266f927/Products/DAHCURVED3ELECTR

I would give this one a ride if I were you. Is it worth that extra money over the Kudos secret? A test ride of both would be my way of finding out.

Again. Folding either one to see if it's transportable is going to be the deal breaker for you. The power difference in those two different motors may be quite noticeable as well.. That Dahon looks pretty sweet. A bit of haggling and you may have the one you've been looking for!

 

[trex]

Thank you for your help.

I am looking at Dahon conversionbikes from CH White and Son....

OR.....

Buying a donar bike and kit... Anywhere you recommend CD kits that will fit a folder? (And also a company that will fit said kit).

Found this bike with automatic hub gears...
https://www.ebay.co.uk/ulk/itm/262365747883

that dahon is a good buy up to £350, good for conversion.
Note that Dahon specify a weight limit too, but I think the 20" wheels are quite capable of taking a little bit more. On the downside, it's a relatively heavy 2-fold with the NuVinci, not easy to carry though.

 

[anotherkiwi]

Apparently there was a family clash in the Dahon family and one of the offspring set up Tern which make really nice folders. I kind of fantasised about putting a mid drive on one, very nice looking bike with good components.

My choice is a GSM with an external controller, preferably in the battery casing. In the motor if things get too hot the controller is the first thing to go pop.

I have also chosen the Nexus 8 Inter over the Alfine because it is reported to be more robust. I have a "clutch" button to mount to my handlebar just in case I need to cut the motor for gear changes. I don't think I will need it because it is very important to train oneself to change gears at he right time, even with a hub motor.

I have nothing against a well set up derailleur but as I am building a new bike I thought I would try a hub just to see what it is like. Oh and I am going to completely encase the transmission in a Hebie Chainglider and leave the trouser clips at home. The other thing being the ability to change down when stopped at the lights/stop sign/behind the woman on her phone...

 

[mike barnard]

In my search for a folding ebike that I can wheel easily, I've been looking at Dahon conversions.
(Incase anyone hasn't read my other posts - My commute is 6 miles, I want a folder I can fold and then tilt on its wheels to roll - the Dahons do this. No public transport to go on, just want a folder so I can store it inside my home and office).

I have a couple of questions I wondered if I could get some advice on?

Question one....I'm looking at the mid drive motors, the options are Bafang or GSM (both 250w with built in controllers) - I've read on here about some issues with the GSM - do they still stand? The GSM option is around £100 less than the Bafang.

Question two....I have the option of either hub gears (3 or 7 gears, depending on the bike I choose) or 8 speed derailleur. I like the idea of hub gears but I'm aware I would need to slow/stop pedalling to change. The hub gears are more expensive. Apart from easy maintaince, less likely to get caught etc - is there any major benefits of hub gears, I.e do hub gears work better with a crank drive motor or does it not make any difference?

Thank you in advance

 

[Geebee]

I imagine it would be very easy to break an Alfine hub with a Bafang CD motor, mess up the complex (brake dab to cut power) gear change and the hub isn't going to like it.

Not in my experience, I have a Tonaro with an 8 speed hub and after riding for an hour or so the tap brake to shift happens without thought, or even easier is to just pedal until the cadence is just starting to lose strong motor assist then shift like an unpowered bike, works great for derailleurs as well.