Are mid drives just naturally less zippy than hub motors?

[Rexlion]

If I hit the throttle 1/2 way on my mid drive off the line it the front tire will wheelie off the ground there is so much torque and it will buck the rider off like a horse. I added some weight to the frame using a larger shark battery pack. This helped with the torque pull and made the drivability off the line a lot less scary. This is with a 52T front chainring. I had a 28T I used that made the bike feel like a F-1 car. The top speed with the 28t was only around 23/25mph but the acceleration was bone breaking fast.

If you're using the throttle, what does the chainring have to do with it? I'm a bit confused by that. I'm referring to using my (thumb) throttle, but it sounds like your "throttle" might be your feet... apples & oranges. Or am I not understanding?

 

[JRA]

I'm curious to know how one sets up a Schlumpf drive when there is a torque or cadence sensor involved with the crank. Any special challenges or limitations?

I believe it states that I don't use PAS as I don't like how it interferes with my natural cadence. I have a throttle that can be easily set to any watt output and locked there like cruise control in a car and match that to my desired cadence instead.

 

[SC00CHB00CH]

If you're using the throttle, what does the chainring have to do with it? I'm a bit confused by that. I'm referring to using my (thumb) throttle, but it sounds like your "throttle" might be your feet... apples & oranges. Or am I not understanding?

throttle refers to the thumb throttle , no pedaling
"throttle only" refers to using the bike like a motorcycle
I was saying if I move the left throttle in just 1/2 way the bike will jump up off the ground like a wheelie and throw the rider off , it has that much torque
the bike weighs about 22kgs with 120nm of torque using just the saddle bag battery

 

[tomjasz]

the bike weighs about 22lbs with 120nm

QFT. Um, so the bike weighs nothing? FFS a battery typically weighs 10lbs and most motors 7lbs so your frame and accoutrements weigh 3lbs? Me thinks you need to retype…

 

[SC00CHB00CH]

QFT. Um, so the bike weighs nothing? FFS a battery typically weighs 10lbs and most motors 7lbs so your frame and accoutrements weigh 3lbs? Me thinks you need to retype…

My apologies the bikes weighs about 33lbs total which is about 14kg , I was thinking kg and not lbs
I'm using a 6AH saddle bag battery under seat which only weighs 3lbs

The donor bike is a SAVA carbon fiber at 22lbs , stock OEM , all gears , brakes everything
the bbso2 weighs about 9.5lbs
the samsung battery weighs 3lbs
I have a shark pack also which you can add to frame via a magnetic mount it weighs 9lbs (which would bring it closer to 22kg)
If I scrap the seat for a ligher one and the pedals and scrap the kickstand I may shave a pound or two

My next build I'm planning on using the 18lb hummingbird folder (18lbs) blue bike

 

[Rexlion]

Okay, now I understand. That SAVA bike appears to have very little weight on the front, so I can see how it would pop a wheelie rather easily. That would contribute massively to a feeling or impression of high acceleration, obviously. In comparison, my ebike weighs more than 50 lbs and the battery is near the front, so it can't pop wheelies that way even though my motor has nearly as much torque (100 nm). I'm going to guess that if we were to hang 20 lbs from the SAVA's handlebar it wouldn't feel so fast at takeoff, because the rear hub would not be allowed to spin up as quickly; it would be forced to push the entire bike straight forward rather than allow the front to resist forward motion and rise up (the path of lesser resistance).

 

[SC00CHB00CH]

Okay, now I understand. That SAVA bike appears to have very little weight on the front, so I can see how it would pop a wheelie rather easily. That would contribute massively to a feeling or impression of high acceleration, obviously. In comparison, my ebike weighs more than 50 lbs and the battery is near the front, so it can't pop wheelies that way even though my motor has nearly as much torque (100 nm). I'm going to guess that if we were to hang 20 lbs from the SAVA's handlebar it wouldn't feel so fast at takeoff, because the rear hub would not be allowed to spin up as quickly; it would be forced to push the entire bike straight forward rather than allow the front to resist forward motion and rise up (the path of lesser resistance).

This was how it was when I sold it recently I put a Luna battery on the frame (see picture) that helped with front wheelies. Although it will still wheelie if you hit full throttle at a stand still. The bike was still fast. Top speed of 36mph with me on it weighing about 220lbs.

 

[Stefan Mikes]

FWIW, my Giant Trance E+ 2 Pro (a mid-drive e-MTB) was doing the wheelie when with maximum assistance and in a low gear.

 

[Jeremy McCreary]

He was saying mid-drives feel more natural IF YOU THE RIDER know how to drive a manual transmission like a car manual transmission.
If you're uncomfortable with manually shifting gears and want an automatic transmission like car then get a hub motor.

If you don't have good knowledge of manual transmission like in a car. A hub motor is going to feel more smooth to you. Not because of the motor itself versus a mid drive but because of your level of skill regarding shifting gears.

Saying hub motors are more zippy than a mid-drive is like saying a turtle is faster than a cheetah. It boils down to simple physics/mechanics of how the motors drive the bike. The video was comparing two 750 watt motors on the same bike , one was a mid-drive and one was a hub motor. Same manufacturer , same battery and the mid-drive was more zippy and had a higher top speed.
You have an actual test putting two motors with the same wattage and both were installed on the same bike , same battery and the mid-drive outperformed the hub motor.
You can dial in both motor types to feel smooth as you want by limiting the wattage of each respective pedal assist range.
My mother couldn't drive my bike to save her life because there is no gear shift sensor and you have to manually shift gears to propel faster. Like a manual car. But she has a pedego hub motor bike which she drives just fine.

Must be reading this wrong. Sounds like you're saying that ebikes with hub motors either lack useful gears or don't benefit from gearing the way mid-drives do.

My Class 2 ebike has a 500W hub motor with torque-sensing PAS, a 9-speed casette, and a single chainring. A common setup here in SoCal.

I've cycled a lot in my time. I use the gears on this ebike all the time -- just like I did pre-ebike, and just like I still do in my 6-speed manual sports car. Changing gears has exactly the same effect as pre-ebike.

Hard to imagine it's a lot different with a torque-sensing mid-drive. What am I missing?

 

[AHicks]

Must be reading this wrong. Sounds like you're saying that ebikes with hub motors either lack useful gears or don't benefit from gearing the way mid-drives do.

My Class 2 ebike has a 500W hub motor with torque-sensing PAS, a 9-speed casette, and a single chainring. A common setup here in SoCal.

I've cycled a lot in my time. I use the gears on this ebike all the time -- just like I did pre-ebike, and just like I still do in my 6-speed manual sports car. Changing gears has exactly the same effect as pre-ebike.

Hard to imagine it's a lot different with a torque-sensing mid-drive. What am I missing?

Nothing....

 

[SC00CHB00CH]

Must be reading this wrong. Sounds like you're saying that ebikes with hub motors either lack useful gears or don't benefit from gearing the way mid-drives do.

My Class 2 ebike has a 500W hub motor with torque-sensing PAS, a 9-speed casette, and a single chainring. A common setup here in SoCal.

I've cycled a lot in my time. I use the gears on this ebike all the time -- just like I did pre-ebike, and just like I still do in my 6-speed manual sports car. Changing gears has exactly the same effect as pre-ebike.

Hard to imagine it's a lot different with a torque-sensing mid-drive. What am I missing?

Yes even though you have 9 speeds , almost all hub motors only allow a single gear ratio. The single largest advantage that mid-motors have over hub motors is their gear ratio. They allow the rider to power the rear wheel via the same chain and gear set as the pedals, which means that a low gear can be selected for powering up steep hills or accelerating from a stop with massive torque. There would be a difference on your bike if it were powered with a mid-drive and 9 gears.

The typical hub motor there is only one gear. Even if there are gears visible on the rear wheel, these visible gears solely affect the power provided by your pedaling – the power delivered via the chain. The rear hub motor itself does not benefit from these gears.

Think about it if you break a chain on your rear hub motor bike , you can still move right at or near to top full speed , you're still powered by the rear hub motor , but what gear are you in ??? The chain is gone so the gear is ONLY one gear ratio. You can't shift gears on a broken chain. Since the power comes from the REAR wheel. If you break a chain on a mid-drive you go nowhere since the entire mechanism is built upon powering the gears. You'd have to walk the bike home.

I think there is a misunderstanding of the mechanics of rear hub motors. Mid-drive motors don’t power the wheel directly like hub motors. Instead, the mid-drive motor provides power through the bike’s drivetrain. IE: THE GEARS

A mid-drive ebike motor can take advantage of the bike’s gears because it is integrated into the drivetrain. You can use the mechanical advantage of the gears to multiply the motor’s power.

For example, when you shift down it becomes easier for the mid-drive motor to turn the cranks. This allows you to easily power up steep hills. When you shift up, the motor has to work harder to turn the cranks. The mechanical advantage of the gears allows you to reach higher speeds. You can also use the gears to keep the motor in its ideal RPM range. Using the gears allows you to ride faster and more efficiently and ride varied terrain.

The hub motor directly powers the wheel it’s built into. In other words, it applies torque directly to the wheel. It operates completely separately from the bike’s drivetrain. A hub motor is not affected by gear changes. Hub motors can’t take advantage of the bike’s gears.

Now YOU can pedal the gears with rear hub motor assistance but the gears are only powered by your feet not the hub motor. A mid-drive motor ADS POWER TO THE GEARS.
This isn't a conspiracy against hub motors it's just how they work mechanically.


Basically think of a rear hub motor as being in 3rd gear always.

 

[SC00CHB00CH]

Nothing....

The typical hub motor there is only one gear. Even if there are gears visible on the rear wheel, these visible gears solely affect the power provided by your pedaling – the power delivered via the chain. The rear hub motor itself does not benefit from these gears.

 

[Djangodog]

The typical hub motor there is only one gear. Even if there are gears visible on the rear wheel, these visible gears solely affect the power provided by your pedaling – the power delivered via the chain. The rear hub motor itself does not benefit from these gears.

Yes, the hub motor powers the wheel directly, but the torque sensor would apply assistance based on the torque furnished by the rider, (or do I misunderstand something here?, which is completely possible).

If that is correct, then the assist system should have the same feel as a mid drive. I ride a mid drive class 1 with a 1x11, 46 to an 11-42. If I had a rear hub motor, I would want that gearing as well.

 

[tomjasz]

Oh FF sake. try a BBSHD as a single speed, ZOOM ZOOM....

 

[SC00CHB00CH]

Yes, the hub motor powers the wheel directly, but the torque sensor would apply assistance based on the torque furnished by the rider, (or do I misunderstand something here?, which is completely possible).

Yes the hub motor adds more assistance to the wheel itself but it's not through the gears or drive-train like a mid-drive.

A rear hub motor can't use the gears , those gears are only powered by YOU , the assistance felt is not through the gears but the motor in the rear wheel propelling you forward. Hub motors do not rely on the gears to propel the bike. They may use a torque sensor to apply more wattage and power to the rear hub motor , but the propelling forward motion of a hub motor is not the rear cassette or gears. YOUR leg power is the only power applied to the gears in a rear hub motor. When the rear hub senses you pedaling hard it applies more wattage to the motor so it may feel as though it were through the gears but mechanically it's not.
You could essentially remove the chain from your rear hub bike and if you had a button on the bike to control torque sensing it would essentially drive just like the bike had a chain on it with gears. It would apply more power or wattage based on the torque sensing. NO CHAIN OR GEARS necessary.

A mid-drive absolutely needs a chain since the forward propulsion relies entirely on the gears.

 

[SC00CHB00CH]

Oh FF sake. try a BBSHD as a single speed, ZOOM ZOOM....

yes I do that all the time , just leave in it one gear it zips around

 

[Djangodog]

Yes the hub motor adds more assistance to the wheel itself but it's not through the gears or drive-train like a mid-drive.

A rear hub motor can't use the gears , those gears are only powered by YOU , the assistance felt is not through the gears but the motor in the rear wheel propelling you forward. Hub motors do not rely on the gears to propel the bike. They may use a torque sensor to apply more wattage and power to the rear hub motor , but the propelling forward motion of a hub motor is not the rear cassette or gears. YOUR leg power is the only power applied to the gears in a rear hub motor. When the rear hub senses you pedaling hard it applies more wattage to the motor so it may feel as though it were through the gears but mechanically it's not.
You could essentially remove the chain from your rear hub bike and if you had a button on the bike to control torque sensing it would essentially drive just like the bike had a chain on it with gears. It would apply more power or wattage based on the torque sensing. NO CHAIN OR GEARS necessary.

A mid-drive absolutely needs a chain since the forward propulsion relies entirely on the gears.

I understand that the motor does not use the gears, but if it is equipped with a torque sensor, the output from the motor is dependent on the output of the rider. If you want to ride efficiently, then you use the gears.

How would a torque sensor sense torque without chain, (the cranks would be freewheeling, nearly zero torque).

 

[SC00CHB00CH]

I understand that the motor does not use the gears, but if it is equipped with a torque sensor, the output from the motor is dependent on the output of the rider. If you want to ride efficiently, then you use the gears.

How would a torque sensor sense torque without chain, (the cranks would be freewheeling, nearly zero torque).

You'd have to create a controller to trick the motor into sensing a certain amount of torque at certain intervals. But this creation does not exist because you don't need it. Unless perhaps your were to build a bike for someone without legs , then perhaps it would be a necessary creation. I was only trying to make it more clear how mid-drives work versus hub motors by using a somewhat hypothetical example.

 

[AHicks]

The typical hub motor there is only one gear. Even if there are gears visible on the rear wheel, these visible gears solely affect the power provided by your pedaling – the power delivered via the chain. The rear hub motor itself does not benefit from these gears.

Geared hub AND mid drive can both excel when properly selected for the job at hand. The fact it runs at a fixed 5:1 ratio, makes the geared hub brain dead simple to ride for starters, and noticeably more "zippy" at speeds under 10mph. Why? No NEED to shift!!!

Place that same 5:1 geared hub in a steep hill or heavy load scenario where it can't get the job done (causing it to overheat maybe), and you've described the exact scenario where the mid drive shines.

One bike cannot possibly excel in both areas where it will outshine the other completely....no bike I know of anyway.

There's a darn good reason I own and ride both types frequently....

 

[Rexlion]

Plainly, a mid drive will provide more mechanical advantage in low gears than in high gears, whereas the hub motor is simply providing the same mechanical advantage no matter what gear you're in (we could get more technical and start talking about motor speed and torque, but I'm keeping it simple). However, from what I've read, when climbing a steep hill the amount of work provided by the legs is considerably greater than the work done by the motor. Without doing any actual measurements, I'm thinking that the difference between roughly equivalent mid drives and hubs is less significant than the strength of the rider. If I ride a torque sensing hub ebike up an incline and then ride a torque sensing mid drive ebike up the same incline, assuming equivalent motor power and assuming the use of the same low gear in each case, I'm confident that the mid drive should feel somewhat easier to pedal up the incline but I don't think it will necessarily feel like a 'night and day' difference. That is my hypothesis.