Are mid drives just naturally less zippy than hub motors?

[MinnBobber]

I totally understand how mid drives use the gear reduction to get more torque BUT a quality hub electric motor doesn’t really need a transmission/ gears.
Look at diesel electro locomotives. They pull 150 tons from a dead stop, via electric motors, and no 12 speed trannies required.

That’s the low end beauty of electric power.
It’s not like a gas engine that needs to build rpm’s to get power.

 

[Jeremy McCreary]

mid drives are more efficient because they operate closer to the optimal speed for the motor. its as simple as that. as long as yousay peddle at 80 rpms them motor will be at the same efficiency despite the speed. a hub drive is only efficient at the sweet spot and thats usually pretty fast the hub motor will only be the most efficient at a set speed the bit drive is the most efficient at normal cadence over the whole range of speed.

May we see the torque/speed, efficiency/speed, and mechanical power/speed curves for these motors, please?

Odd thing is, not once on today's beach trip did I think about efficiency. Not in the stiff headwind. Not on the short but steep hills up to our terrace.

Just grinned the whole way there and back, the hub motor and I working together at 14-18 mph most of the time.

 

[AHicks]

@SC00CHB00CH
I think you have a lot of great ideas, but thinking maybe you're lacking overall experience/seat time with the different options available here. What the hell am I talking about? Get back with us when you've built and spent some time with a similar bike with GMAC power, a 1000w MAC geared hub, or maybe one of the new Bafang 1000w geared hubs for instance. Then you can compare apples with apples best possible.

The subject being discussed here has NOTHING to do with how fast your bike or any other bike will go. This is way more about a drag race to 10mph or so. Who can cross the road in the quickest manner possible. Zippy......

Comparing what you have going on with your bike is hardly typical.... but I'll give you a hint. All else being equal, I feel pretty safe predicting your bike will be smoked in a race across a street by one just like it with a 1000w+ geared hub power and a power supply that will stay up with it (35a+). Beyond that, for our subject at hand, nobody cares....

 

[SC00CHB00CH]

@SC00CHB00CH
I think you have a lot of great ideas, but thinking maybe you're lacking overall experience/seat time with the different options available here. What the hell am I talking about? Get back with us when you've built and spent some time with a similar bike with GMAC power, a 1000w MAC geared hub, or maybe one of the new Bafang 1000w geared hubs for instance. Then you can compare apples with apples best possible.

The subject being discussed here has NOTHING to do with how fast your bike or any other bike will go. This is way more about a drag race to 10mph or so. Who can cross the road in the quickest manner possible. Zippy......

Comparing what you have going on with your bike is hardly typical.... but I'll give you a hint. All else being equal, I feel pretty safe predicting your bike will be smoked in a race across a street by one just like it with a 1000w+ geared hub power and a power supply that will stay up with it (35a+). Beyond that, for our subject at hand, nobody cares....

My bike has a 750 watt bafang BBS02 it should be beat by a 1000 watt geared hub bike. But I would still bet $5 on winning.

Those mac geared hubs are awesome. I may just do the hummingbird with one instead of a mid-drive. I think they can do a sustained 1700 watts and be pretty stable.

These are the stats for my 750 watt BBS02 motor.
There is (rated watts = 750w)
There is (max watts = 1470w)

I've seen some rear hub motors at 250 watts hit crazy high 2000 watts peaks.
When someone says 1000 watt motor, that is usually the "rated" watts ,some 1000 watt rated hub motors can hit 3000 watts peak safely for short bursts , like full throttle , going up hills , etc. or sustained watts from the mac geared hub around 1700watts continuous. It called a 1000 watt hub though.

My bike will absolutely zip to 10mph across the road. In fact there is so much torque the front wheel will jump off the ground.
In fact when I change the front ring to a 28teeth front it will zip like crazy.

Oh look at this picture , a rear hub 1000 watt mac geared hub. I wonder who built it?

 

[SC00CHB00CH]

May we see the torque/speed, efficiency/speed, and mechanical power/speed curves for these motors, please?

Odd thing is, not once on today's beach trip did I think about efficiency. Not in the stiff headwind. Not on the short but steep hills up to our terrace.

Just grinned the whole way there and back, the hub motor and I working together at 14-18 mph most of the time.

View attachment 139335

You're bike looks awesome and if you're having fun than that's all that matters.

 

[fooferdoggie]

May we see the torque/speed, efficiency/speed, and mechanical power/speed curves for these motors, please?

Odd thing is, not once on today's beach trip did I think about efficiency. Not in the stiff headwind. Not on the short but steep hills up to our terrace.

Just grinned the whole way there and back, the hub motor and I working together at 14-18 mph most of the time.

Bosch does not really publish much info. but you can read how people get 50 to 100 miles on a 640 watt 36v battery. my riding at 18mph on a flat I would get around 50 miles on a single battery. it depend on how much you ride and how many hills you climb and how far you want to be able to travel on your battery.

 

[m@Robertson]

May we see the torque/speed, efficiency/speed, and mechanical power/speed curves for these motors, please?

You can use the Grin Tech motor simulator to cook up just about whatever you want. It is widely recognized as being pretty much dead-on accurate in builder circles.

Motor Simulator - Tools

Our ebike motor simulator allows you to easily simulate the different performance characteristics of different ebike setups - with a wide selection of hub motors modeled, and the ability to add custom batteries and controllers and set a wide variety of vehicle parameters you'll be able to see...

ebikes.ca

You'll want to look down the left side where the parameters are and choose Open System B to give yourself a direct comparison on one screen.

In builder circles, its generally accepted that mids are more efficient than hubs in terms of the power they eat. Recently I have been playing around with efficiency on very long hauls on my 2wd cargo bike, where I have a front hub and a rear mid. Just in looking at the amps and watts needed for the two motors individually as I toodle down a long, flat straight stretch of road, I've been playing with balancing the output between front and back to improve range. Looking at the outputs, I've been reminded of how mids sip power at cruise as well as under pedal assist. However, you can tuirn this on its head by hammering the throttle, or even using the factory programming and not rolling your own that is aimed at converting electricity to forward motion and minimizing how much is instead converted to heat.

I haven't been in this thread for awhile... and after a quick perusal of the last few pages it looks like the bars have emptied out, the moon is full and not everyone has stayed on their meds.

 

[SC00CHB00CH]

 

[Jeremy McCreary]

Still struggling to understand how I could be enjoying such a fundamentally flawed ebike.


Stranger yet, it even feels like a bike.

 

[fooferdoggie]

Still struggling to understand how I could be enjoying such a fundamentally flawed ebike.

View attachment 139338
Stranger yet, it even feels like a bike.

your starting to get silly. but it does not feel like a regular bike unless it has a torque sensor.

 

[tomjasz]

Still struggling to understand how I could be enjoying such a fundamentally flawed ebike.

View attachment 139338
Stranger yet, it even feels like a bike.

Some great posts, but now don’t be a one bike wonder (expert).

 

[Jeremy McCreary]

your starting to get silly. but it does not feel like a regular bike unless it has a torque sensor.

It does have a torque sensor.

 

[Jeremy McCreary]

Some great posts, but now don’t be a one bike wonder (expert).

Fair enough. Based on the things I've learned here, I'll definitely try a mid-drive someday. Maybe you guys could teach me how to talk my wife into it.

 

[alloo]

I have owned both mid and hub drive ebikes. I wonder how the Aventon Level 2 feels like compared to a mid drive bike? The Level 2 is a hub drive with a torque sensor. They're have been occasions where my mid drive chain has broken and I've had to walk the bike home. On the other hand, I had a chain break on my hub drive and I've used the throttle to get home. I think that they're a market for both drives. If you live in a relatively flat place hub drives work fine. If you live in the mountains mid drives work well. The real bike fake bike thing is hogwash both are bicycles. Sometimes it's a financial ego thing where I can afford a more expensive thing. Use what works for you, everyone has their own likes and this likes, we don't all have to resort to group think. It's like the Harley vs other cruisers, scooters vs Vespa, ebikes vs mopeds, it really doesn't matter since all opinions stink anyway. lol Enjoy riding.

 

[alloo]

I wonder which motor is better in snow? Mid Drive or Hub Motors?

 

[SC00CHB00CH]

I wonder which motor is better in snow? Mid Drive or Hub Motors?

Both would be good with the right tires.

I think a dual hub motor (one motor in the front wheel and one motor in the rear) with the right tires would excel in the snow over a comparable mid-drive. But there are tons of videos on youtube of both bike styles excelling at snow. You've got to think of battery life. With two 500-1000 watt hub motors ,they'll suck precious battery life.
So again , pros and cons.

There is a 2wd drive bike that can be powered by a mid-drive made by Christini. Kate Leeming will use a version of this bike to cross Antarctica without a motor.
I think she's set for 2023 to start her attempt. She's set many cycling records already.

The 2wd bike uses a system of gears front tire and rear combined and can be combined with a mid-drive motor. Essentially you have one mid-drive motor taking advantage of the gear system.

He sells regular 2WD drives bikes without a motor as well as mid-drive versions.

 

[AHicks]

"Better" is completely subjective. The "better" drive system is going to depend on the mission and the rider. There is absolutely no getting around that idea. I don't know why we can't seem to get past this?

A favorite example I like to use. The "better" bike for a rookie e-bike rider with no recent riding experience (that's just one of a lot of different examples I can think of. Another might be a shy rider with NO confidence) that's been invited over to go for a ride on mostly flat paved surfaces ?

A 500w geared hub plain vanilla bike w/throttle, or an Ultra (gorilla) powered mid drive bike. You have both on hand fully serviced and ready to go. Which one is your guest going to be offered?

My wife, who has been my riding partner for quite some time (20 years?), and on e-bikes since 2015 (with thousands of miles experience/seat time), flat refuses to ride either of our mid drives, both torque sensing w/throttles. Should I leave her at home, or let her ride whatever the hell she feels like, regardless of what anyone else thinks is "better"?

A simple throttle equipped geared hub bike (250w or 1000w, makes no difference) makes for a brain dead easy to ride bike that will do an excellent job under a lot of conditions. To disregard something like this in favor of mid drive (torque sensing or not) for it's "natural feel" in many (most?) situations is a serious mistake. EASY to ride will always be a desirable attribute.

That's NOT to say the mid drives should be discounted completely. Their attributes have been beat to death so there's not any point in repeating them here. I WILL say, that under a lot of conditions, they might make a better second bike than a first.... -Al

 

[m@Robertson]

There is a 2wd drive bike that can be powered by a mid-drive made by Christini.

The Christini system is not quite what a lot of people think it is. It is not two wheels powered at once. There is a slight gearing differential - I think its like 97%. Maybe 95%. That keeps the front wheel from being actively powered. If the rear wheel slips, the front wheel takes over and pulls you out of your slide. When the rear stops slipping, it automatically shifts back to being primary. Its a subtle but significant difference. You aren't looking at more power so much as you are looking at it shifting fore and aft, as needed in the moment. He was interviewed on the Area 13 podcast awhile back after meeting the shop owner at Sea Otter. Its worth a listen if you want more on that concept.

Having done a few generations of 2wd bike myself, I can say they are pretty awesome. I have years, and thousands of miles, commuting on a hub/hub version, and my mid+hub can go places no other 2-wheeled bike can.

Dual Motor AWD Electric Bikes – Case Study: Fat Trail and Hill Climber

Built to conquer the weakness of twin hubs in hills – and eliminate the damage a mid drive does to an ebike’s drivetrain. The bike I call 2Fat did all that.

talesontwowheels.com

The question of whether a hub or a mid would work better in snow is moot. The tires and their inflation will decide that, up to the point where the single powered wheel is overwhelmed (the front wants to submerge from being pushed into the soft ground unless its powered and can pull itself up/out). Whether a hub is better than a mid in that world will be all about steepness. of the grade just like it is on dry ground.

 

[tomjasz]

Fair enough. Based on the things I've learned here, I'll definitely try a mid-drive someday. Maybe you guys could teach me how to talk my wife into it.

You're happy. Enjoy your ride. You can't miss something you don't need. If my first bike was a hub drive I may never have moved on. As it's panned outI really don't need a mid-drive. But I ended up selling supporting and building with them. But have gone back to hub drives. Sadly, especially for my wallet, I like it ALL. Rear, front, direct drive, gear drive, and, mid drives. As the song goes, Love The One You're With

 

[tomjasz]

I wonder which motor is better in snow? Mid Drive or Hub Motors?

BBSHD or any high-power Bafang mid with fat tires. Says he who rides all winter in Minnesnowta.
I expect my 2.5" 9C front drive studded tire Day6 trike to be a winter snow beast. We'll see...