Mid Drive Motors : An overview

[Bike_On]

From the other EBR (Electric Bike Report), Pete details a very good and fairly comprehensive list of mid drive motors and their respective bike platforms. (I think he left off the R Martin- Evelo)

http://electricbikereport.com/mid-drive/

My 2C: Hubs use to be cheap, more reliable, and mid drives more expensive, less reliable. That is becoming less of a reality. With the new Bafang BBS02 mid drive, the DIY mavericks are cutting into the OEM MD sales because it is easy to install and works well. DIY kits have been known to look like wire monsters and a zip tie city. A center battery and MD motor limits that mess. OEMs are producing better performing, lighter MD bikes, less noise, better shift technology, drive train performance and bikes cheaper than before.

Mid drives will ALWAYS be best for a balanced ride, off road efficiency, higher torque, better overall range with freewheel ,natural bike feel. Remaining limitations are reduction gear noise, limited max power due to drive train wear and limits.

My top 5 motors:
1. Optibike SIMBB/MBB
2. Derby Cycle Impulse 2
3. Bosch Gen 2
4. Shimano Steps
5. Bafang BBS02

 

[George S.]

I remember when they first announced the Bosch mid-drives in the US. It was supposed to be the 'future', but I choked a little when the early news said it would 'add' $2500 to the price. I still tend to frame mid-drive in terms of price.

It's awkward when a super-premium company like Stromer goes for a hub. If mid-drive is the 'only' choice, why would they do that? And there are other super-premium hubs, apparently.

The review sites don't seem to offer the big picture, just a lot of little pictures and specs. I'm not sure Court or Pete or "Turbo" can really write an essay about the 'best' drive, from their experience. They compartmentalize. So who do I trust? I'd probably trust Ravi as the man of experience. He seems to be a hub guy, with the Stromer and the JR ebikes.

I have two quirky hub bikes. The Prodeco X3 is dismally engineered for balance. But it never seemed to be difficult to adjust to the coarse (that is charitable) handling. I have a front hub that solved a lot of the wiring issues, and it has quite pleasant handling. The front hubs can be a pain because they don't maintain direction in something like loose rock, but the overall experience is pleasant enough. The front hub is easy to remove to change a tire. The rear hub, the X3, is not.

I have to ask if an electric bike really needs to handle like a regular bike. If we are talking cruiser bikes, how nimble are they, anyway? Fat bikes? I almost think we add power to some bike designs to overcome the design faults, like cruisers and fats. I think a Prodeco X3 would be about 5% better if it had better weight distribution. It's just fluff, I guess.

I'll go for front hubs as best. You leave the drive train alone. The wiring is generally quite simple. They work for reasonable amounts of power, and people should use steel forks and torque arms. I'm not talking off road. I can do local hills, up to about 14%. The geared hub rides well without power.

How 'pure' do we have to be? What is the real range of riding experience between the ideal, perfectly balanced bike and the bike designed only for convenience and low price? When I was riding for transportation, I was lugging 15 pounds of books on the back. Now I lug a battery. The overall efficiency of an ebike tends to trump everything else, for me. I am not a purist. The level of technical perfection I demand might be 70%. Others seem to demand more. I think 70% makes for a really nice and usable bike. And it can be made for a reasonable price.

 

[flymeaway]

With the new Bafang BBS02 mid drive, the DIY mavericks are cutting into the OEM MD sales

There is a significant advantage to offering a mid-drive system that will retrofit most bike frames. The glaring drawback I can see to the other mid-drives (when considering price/performance) is the integration into the frame. Aesthetically pleasing for sure and undoubtedly well engineered, but the unique frame design required will automatically make the finished product more expensive. Bafang has an enormous jump on their competitors in the mid-drive retrofit market and I'd advise them to continue to engineer in better performance, reliability and integration in their BBS line. If they remain committed to improving BBS they probably will dominate the segment.

Court J.

 

[PowerMe]

New technology will emerge and existing tech will continue to evolve and that will help make powered ebikes less expensive over time. There will always be premium (i.e. expensive) ebikes with the most upscale options of course, but mid drive technology won't be out of reach for as many in a matter of a couple years or so. Remember bluray players cost $thousands when they first came out and can be had for well under $100 now. And so it goes...

 

[flymeaway]

Remember bluray players cost $thousands when they first came out and can be had for well under $100 now. And so it goes...

This is true, but the comparison is a bit optimistic. The base motor and electronic control technology is quite mature so driving the cost down is more a function of economies of scale then technology improvements. Not considering transportation cost, I think a selling price of $500 for the BBS02 750W kit is very reasonable. The area where technology could improve and cost drop is the battery. It would be great to be able to buy high quality, high capacity batteries for something less than $300, "bolt on ready" .

Court J.

 

[PowerMe]

I don't expect mid drives to ever be less than $100, but at some point they shouldn't add over $1000 to the cost of an ebike (hopefully).

 

[Bike_On]

This is true, but the comparison is a bit optimistic. The base motor and electronic control technology is quite mature so driving the cost down is more a function of economies of scale then technology improvements. Not considering transportation cost, I think a selling price of $500 for the BBS02 750W kit is very reasonable. The area where technology could improve and cost drop is the battery. It would be great to be able to buy high quality, high capacity batteries for something less than $300, "bolt on ready" .

Court J.

Court,
Very true that the building blocks for the technology is mature: Bike+ Motor+controller+battery, with the motor technology approaching the physical limits and designs are solid and cost effective. Yet people are always striving to improve over the traditional 3-phase hub:
Bionx- a 3 speed hub
Optibike - first to have a motorized bottom bracket
Falco- 7, and now 5 phase hubs
Assortment of light geared hubs, front and rear
Power hubs from Crystalize
Better thermal properties and lighter hubs: Ultra, Go Swiss, Xion

You are correct that Bafang has done well with their BBS01-02 and it is a formidable option.

I have seen decent 48V, 11 ahr batteries for near $350-400, and a BBS02 for what? $400. One can get an ebike on the road for under $1000 if they have a bike.

 

[Bike_On]

I remember when they first announced the Bosch mid-drives in the US. It was supposed to be the 'future', but I choked a little when the early news said it would 'add' $2500 to the price. I still tend to frame mid-drive in terms of price.

It's awkward when a super-premium company like Stromer goes for a hub. If mid-drive is the 'only' choice, why would they do that? And there are other super-premium hubs, apparently.

The review sites don't seem to offer the big picture, just a lot of little pictures and specs. I'm not sure Court or Pete or "Turbo" can really write an essay about the 'best' drive, from their experience. They compartmentalize. So who do I trust? I'd probably trust Ravi as the man of experience. He seems to be a hub guy, with the Stromer and the JR ebikes.

I have two quirky hub bikes. The Prodeco X3 is dismally engineered for balance. But it never seemed to be difficult to adjust to the coarse (that is charitable) handling. I have a front hub that solved a lot of the wiring issues, and it has quite pleasant handling. The front hubs can be a pain because they don't maintain direction in something like loose rock, but the overall experience is pleasant enough. The front hub is easy to remove to change a tire. The rear hub, the X3, is not.

I have to ask if an electric bike really needs to handle like a regular bike. If we are talking cruiser bikes, how nimble are they, anyway? Fat bikes? I almost think we add power to some bike designs to overcome the design faults, like cruisers and fats. I think a Prodeco X3 would be about 5% better if it had better weight distribution. It's just fluff, I guess.

I'll go for front hubs as best. You leave the drive train alone. The wiring is generally quite simple. They work for reasonable amounts of power, and people should use steel forks and torque arms. I'm not talking off road. I can do local hills, up to about 14%. The geared hub rides well without power.

How 'pure' do we have to be? What is the real range of riding experience between the ideal, perfectly balanced bike and the bike designed only for convenience and low price? When I was riding for transportation, I was lugging 15 pounds of books on the back. Now I lug a battery. The overall efficiency of an ebike tends to trump everything else, for me. I am not a purist. The level of technical perfection I demand might be 70%. Others seem to demand more. I think 70% makes for a really nice and usable bike. And it can be made for a reasonable price.

George,

All very good point. When it comes to What ebike should I get? It will certainly differ with each persons needs, wants and means. It seems the decision drivers are (by priority)
1. cost
2. power performance (motor size/battery size)
3. Style, looks, fit
4. Handling, accessories (brakes, suspension, lights, ride feel)
5. Safety (will I die ?)

 

[flymeaway]

shouldn't add over $1000 to the cost of an ebike (hopefully).

With the battery I agree. I believe the delivered price from em3ev is around $600, for the complete kit. I haven't priced the other mid-drive systems, but I believe the frame integrated products are much more expensive and probably will not drop significantly unless they can sell much larger volumes.

Court J.

 

[Ann M.]

Court,
Very true that the building blocks for the technology is mature: Bike+ Motor+controller+battery, with the motor technology approaching the physical limits and designs are solid and cost effective. Yet people are always striving to improve over the traditional 3-phase hub:
I have seen decent 48V, 11 ahr batteries for near $350-400, and a BBS02 for what? $400. One can get an ebike on the road for under $1000 if they have a bike.

Just curious, @Bike_On where are you finding decent 48V LiIon batteries for that price? Please share!

 

[Bike_On]

https://bmsbattery.com/71-48v-li-ion

Not without some risk, mind you!

Also em3ev has good prices, but shipping adds.
http://em3ev.com/store/index.php?route=product/category&path=35

 

[George S.]

Just curious, @Bike_On where are you finding decent 48V LiIon batteries for that price? Please share!

I've looked at the BMS site a few times. There are several stores on Aliexpress with similar prices. You can tell by the Aliexpress feedback profiles this is just starting. I don't see too many actual experiences. I think BMS has some good and bad user experience. The Sondors people are group buying a 36/12 battery for around $300. I see Samsung cell prices on Aliexpress that would support making packs for these prices. But nothing is quite solid enough to really trust. It's too bad review sites don't have budgets to experiment with some of these packs. We have a pretty good idea what the packs for the CF bikes 'cost', especially since some have extra packs available.