HUB vs MID DRIVE - how can I compare?

[JRA]

It shouldn’t be about one system vs another system but which system works best for your needs.

Some will find it most expedient and convenient to follow the big manufacturers use and development of mid drives and their distribution and service channels. Nothing wrong with that but also not the end all be all solution for every current or potential e biker.

 

[Ken M]

Great point ... actually that was my intent. The issue is that it is difficult to find unbiased information. Manufacturers don't want to say a mid-drive is best for say mtn biking but less suited for fast urban pedelec riding. It is next to impossible to find information on long term cost of ownership of the different drive systems - chain & chain ring replacements, maintenance of the motor, etc., but my guess is that a hub motor is dramatically superior in this regard (this is something that universally matters regardless of rider needs but will fall way down the list of important factors for any enthusiast riding a high performance mountain bike).

Mtn biking has some unique performance demands that riding in an urban environment simply does not so in my opinion what should be considered best for you needs for urban riding should be best efficiency of the system. Vice versa, it makes no sense to put a 5kg hub motor on a full suspension eBike because that much mass will ruin the performance of the rear suspension and without a doubt mid-drives are more efficient for low speed climbing (the benefits of the motor's internal gearing and the gearing of the drive train both aid in this).

 

[TForan]

I don't care one way or the other, I just want whatever is the most "bike like"and has great climbing ability. My bike will cruise in the high twenties and on a fat bike, that's plenty for me. 40MPH ? No, thanks.

 

[Ken M]

I don't care one way or the other, I just want whatever is the most "bike like"and has great climbing ability. My bike will cruise in the high twenties and on a fat bike, that's plenty for me. 40MPH ? No, thanks.

As stated, if you like to ride slow and care most about hill climbing performance a mid-drive is the best solution. If urban commuting is the priority where time is money then speed matters and hub drives are simply a better drive system.

I have a saying .... "If you don't want to ride faster than 20mph, then walk." I don't work in the public sector so when I'm commuting on a bike I have to consider my commute time - I'm self employed and time is money.

http://www.ebikes.ca/learn/why-hub-motors-are-awesome.html

 

[TForan]

As stated, if you like to ride slow and care most about hill climbing performance a mid-drive is the best solution. If urban commuting is the priority where time is money then speed matters and hub drives are simply a better drive system.

I have a saying .... "If you don't want to ride faster than 20mph, then walk." I don't work in the public sector so when I'm commuting on a bike I have to consider my commute time - I'm self employed and time is money.


http://www.ebikes.ca/learn/why-hub-motors-are-awesome.html

How fast do you ride, Ken ? When I ride around town 28 is about it for me with a fatbike. I can see with a commuter bike and good roads, maybe a little faster. Riding faster than that in a urban situation, is a little crazy to me.

 

[Ken M]

How fast do you ride, Ken ? When I ride around town 28 is about it for me with a fatbike. I can see with a commuter bike and good roads, maybe a little faster. Riding faster than that in a urban situation, is a little crazy to me.

Good question. There is actually some studies on average riding speed for people that own Class 3 45kph speed pedelec in Europe. They average around 20mph/32kph so that data can make people think that there is no value to having a faster bike. Most of time I'm commuting (not stopped at a light) I'm cruising at around 23-25mph/40kph (my PIM/Polaris eBike assist ends at that speed so it's a comfortable cruising speed. But there are some long stretches I go faster but essentially on under my own power and I'm on the road where it would be nice to get up to 35mph/50kph crusing speed.

I have Schwalbe Moto X 27.5 x 2.4 tires on this bike and they provide the performance and handling that make higher speeds feel comfortable/safe. Just because an eBike has the capability to assist up to 50kph doesn't mean responsible riders are going to be running over pedestrians (although I would prefer they walk in the grass ) and running slower riders into the ditch (although like some bad drivers inevitably they end up there anyway). Anyway, I'm just joking around but when you are commuting approx 15 miles each way as often as possible (my bike does not replace my car) having the higher speed capability does save time. IT'S IMPORTANT! Bizarre that Europe has Autobahns with crazy high speeds for cars but they think bikes should be literally manufactured with speed limitation build in (I guess the conservatives were thrown a bone on that legislation as that is the only explanation I can come up with as to why they did this - sorry conservatives but you did fight to keep the highway speed limits here in the US at 55mph....thankfully you lost that debate...your scared of speed, I can respect that so stay in the slow lane and let me pass).

 

[Ken M]

Good question. There is actually some studies on average riding speed for people that own Class 3 45kph speed pedelec in Europe. They average around 20mph/32kph so that data can make people think that there is no value to having a faster bike. Most of time I'm commuting (not stopped at a light) I'm cruising at around 23-25mph/40kph (my PIM/Polaris eBike assist ends at that speed so it's a comfortable cruising speed. But there are some long stretches I go faster but essentially on under my own power and I'm on the road where it would be nice to get up to 35mph/50kph crusing speed.

I have Schwalbe Moto X 27.5 x 2.4 tires on this bike and they provide the performance and handling that make higher speeds feel comfortable/safe. Just because an eBike has the capability to assist up to 50kph doesn't mean responsible riders are going to be running over pedestrians (although I would prefer they walk in the grass ) and running slower riders into the ditch (although like some bad drivers inevitably they end up there anyway). Anyway, I'm just joking around but when you are commuting approx 15 miles each way as often as possible (my bike does not replace my car) having the higher speed capability does save time. IT'S IMPORTANT! Bizarre that Europe has Autobahns with crazy high speeds for cars but they think bikes should be literally manufactured with speed limitation build in (I guess the conservatives were thrown a bone on that legislation as that is the only explanation I can come up with as to why they did this - sorry conservatives but you did fight to keep the highway speed limits here in the US at 55mph....thankfully you lost that debate...your scared of speed, I can respect that so stay in the slow lane and let me pass).

FYI - I'm 56 years old and have multiple fused vertebrae from a degenerative arthritis (in remission but the discs are fused already) so I definitely do not want to have a high speed wreck on my eBike. I ride at the speed that I feel safe at but that speed is sometimes faster than 20mph or 28mph which legislators, that probably never rode a bike faster than 20mph, feel should be the max speed an eBike can be produced to go......and then these guys/gals have such a bad reputation.

We need more people to start getting out of cars and on commute solutions that are more rational - an eBike uses like 1/50th the energy of a car so they make sense. Now I get all the burly idiots chiming in that it's god-given right to drive their 8000 truck because the were born with a small member. I get that.

 

[JRA]

My average speed is mostly in the mid teens on the mixture of terrain and road surfaces I generally do at a pace that I couldn't do under my own power. Today's 38 mile/2800' elevation gain ride for example was a 16 mph avg speed and a top speed of 38 (downhill with at tailwind no motor). 30 yrs ago I could have done the same thing on my push bike. I don't ride to race, but for exercise induced relaxation.

How I arrived at using a front hub motor was after years of trying all the different types of motor assist and drives possible, including gas ones. It works best for my needs and everyone should use what works for them. Quite frankly especially if it is your first e bike I wouldn't spend a ton on it because you may decide that you want more or less from your e bike experience after you get more with the program.

 

[Leon Washington]

Wondering why a company like Specialized would eliminate the rear hub drive and go with the mid - drive. The Specialized Turbo S looks like a pretty nice ride.

Thank you for this post. . . I thought I was missing something. When the Turbo S went on "Clearance", I grabbed it. It was next to the new Specialized mid-drive model. I asked the salesman (who didn't know much about electric bikes), hey, isn't this cheaper one faster and farther range? He said test drive them and see. Needless to say I have a "new" discontinued Turbo S. Awesome bike so far; not as good as my Stromer. . . . But for less than half the price, great bike. I ride a 7% 2 mile hill to work. I have a top-of-the-line Haibike (speed pedalec), the Stromer and the Turbo S leave the Haibike in the dust, at a standstill start. If I hadn't lost my Garmin a few weeks ago, I would have posted some screen shots.

Oh, and I'm not trying to start a feud, either.

 

[Leon Washington]

I wanted to add some very relevant information that no one seems to ever mention when comparing mid-drives and hub motors.

Mid-drive do tend to be excellent climbing systems because they benefit from the drive ratio of the front to rear sprockets at slow speeds where the torque of the motor can actually be increased to the rear wheel. The problem is that at high speeds that advantage becomes a disadvantage. If you say running at 20mph on a 44T front and 11T rear sprocket only 1/4th the axle torque of the mid-drive is delivered to the rear wheel because of the 4 to 1 reduction to achieve the speed at a reasonable cadence. In my opinion this is the equivalent of inefficiency - decreases the drive system efficiency because an 80nM mid drive will only provide 20nM of torque to the rear axle at that speed.

Hub drives (at least the gear-less more simply ones) do run at lower RPMs which is a less efficient dymanic state for a brushless motor but the torque is delivered directly to the rear axle. So if you are riding at 20mph, a rear hub motor only needs to be providing 20nM to equal the "effective" power of the mid-drive at this speed. The higher the speed the more efficient a rear hub motor becomes so I would venture to say that if you spend a significant % of your riding time over speeds of say 15mph a hub drive may be more efficient and provide more power to the rear wheel.

I would venture to say this is why some of the premium speed pedelecs still utilize hub drive motors.

If you think you will spend the bulk of your riding time below say 15mph and on trails, no doubt get a mid-drive but if you want a fast urbam mobility bike I would give hub drives serious consideration.

I have both a mid drive Haibike and a rear hub Polaris and the Polaris has better fast performance and the Haibike with the Yamaha mid-drive is awesome up to about 15mph. I think the Bosch mid-drives with the smaller front chain ring that spins at 2.5X cadence do provide better high speed assist than the Yamaha but at the cost of some low speed torque to the rear wheel.

This post was really helpful, and from my experience, I whole heatedly agree. I ride the back roads to work with my speed pedalec, mid-drive mountain bike. My DD hubs just get me from point A to Point B on paved surfaces really fast. Thankfully I have a loud horn.

 

[Trail Cruiser]

Thank you for this post. . . I thought I was missing something. When the Turbo S went on "Clearance", I grabbed it. It was next to the new Specialized mid-drive model. I asked the salesman (who didn't know much about electric bikes), hey, isn't this cheaper one faster and farther range? He said test drive them and see. Needless to say I have a "new" discontinued Turbo S. Awesome bike so far; not as good as my Stromer. . . . But for less than half the price, great bike. I ride a 7% 2 mile hill to work. I have a top-of-the-line Haibike (speed pedalec), the Stromer and the Turbo S leave the Haibike in the dust, at a standstill start. If I hadn't lost my Garmin a few weeks ago, I would have posted some screen shots.

Oh, and I'm not trying to start a feud, either.

Man, I would feel like in e-bike heaven with those puppies!

 

[Rooster]

-Ohm
-Bulls Outlaw
-Smartmotion
-The new generation Easy Motion hub drives
-Juicebikes CCS - Torah names his power assist as "dynamic assist", no jerky on-off propulsion.
-Radcity
-Magnum- some riders report jerky on-off feel at low speeds.

I have the juiced ocean current and can attest to the torque sensing on that, Tora definitely got that right.

 

[Ed P]

Enjoyed Mike's erudite post last month on this topic. I have a Kalkhoff Include 8 Premium (with which I have been v pleased), and thought it was a Hub, but I guess it is actually a Mid-drive--is that right?

 

[The duke]

What a great and informative thread. I read every post and every link! My local ebike salesman told me if I climb a paved road with a 10% grade for 3 miles on a hub motor, the motor would burn out after 50-75 trips. I asked him if a geared hub would help that. He said the difference between the gears is extremely small and wouldn't make a significant difference.

I wonder what pace I would have to maintain up that hill to keep a bafang 750w hub motor happy and cool....I'm thinking 10mph? Is it true the geared hubs do that little to address the slow climbing/overheating problem?

 

[indianajo]

I haven't burned any hubmotors yet, and I have some significant short 15% grades on my routes.
I have to say buying a mid drive marries you to electricity. Whereas I ride without power most of the time unless I can blast across a 6 lane highway before the light turns red. Or today, when the wind was gusting 68 mph in my face. **** global warming, it never used to blow this hard here. I think the salesman is blowing it out his *** because he gets higher commission on the more expensive mid-drive.
Vendors are getting out of selling 48 v geared hubmotors, replacing them with 36 v. I think perhaps
people are over accelerating and stripping gears. electric-bikes.com cancelled my order for geared hubmotor because "you are too heavy" at 170 lb me and 60 lb supplies, and I refused to buy a 36 v battery . ebikeling.com has dropped 48 v geared hubmotors. I want one, this 1000 w DD motor is dragging me down 2 sprockets and 25% of my speed unpowered. Geared hubmotors don't drag unpowered. Luna still has a MAC rear geared hubmotor, maybe next week I'll order it. The ebikeling geared hubmotor I do have is a front drive, and I've changed my mind about that. The hubmotors themselves are $180 to $350, less than 15% of the price of the bike shown left. Always remember, if you burn out a hubmotor, you can still pedal home. I've done it thrice with defective batteries. You destroy a mid-drive, you call for a tow truck or push it home.

 

[erider_61]

My local ebike salesman told me if I climb a paved road with a 10% grade for 3 miles on a hub motor, the motor would burn out after 50-75 trips.

While I am no expert on hub drives, I believe most motors today have thermal limit cutoffs in the controller and will shut down before the temps in either motor or co

 

[harryS]

Temp sensors are more common in commercial mid drives because the controller is already in the motor. Just stick it on the circuit board and use it to shut down everything when hot. I'm sure Bosch does that. I don't know about the Bafang Ultra, but the BBS02 and BBSHD don't have them.

With a hub motor, the wiring to it already is chock full of wires. Asking for another wire for a temperature sensor will just tick off the head designer, but I believe some of the really big motors advertised for heavy duty work might have them.

Indianjo knows his big DD motor inhibits pedaling. I believe him. I will say though that my Bafang BBS02 middrive spins free, while my Tongsheng TSDZ2 middrive (still in box) does not. I can feel the friction when I turn the pedal arm on the Tong Sheng. Geared hub motors only have the slight friction of the clutch, imperceptible when coasting,.

10' grade for 3 miles? Wow, sounds like something I'd want to avoid, unless it's scenic. I'm told that Going to the Sun Road (Glacier) is 6' for 12 miles. I think I and my 500W ebikes could do that, given many cyclists do it now on touring bikes with only 200W of power. I wouldn't expect to glide up on thottle, but add my meager output to the pedals.

 

[The duke]

10' grade for 3 miles? Wow, sounds like something I'd want to avoid, unless it's scenic. I'm told that Going to the Sun Road (Glacier) is 6' for 12 miles. I think I and my 500W ebikes could do that, given many cyclists do it now on touring bikes with only 200W of power. I wouldn't expect to glide up on thottle, but add my meager output to the pedals.

It's not scenic.....it's the end to my daily ride home. Could you do it with a rear hub motor?

 

[harryS]

It's not scenic.....it's the end to my daily ride home. Could you do it with a rear hub motor?

I do own a Bafang G60 series fatbike motor. Justin Le at Grin EBikes has modeled this motor on his simulator.
https://www.ebikes.ca/tools/simulat...C&cont=C25&grade=10&axis=mph&wheel=28i&hp=100

He says it will overheat on a 10' grade after 12 minutes. If he sez so.

 

[The duke]

I do own a Bafang G60 series fatbike motor. Justin Le at Grin EBikes has modeled this motor on his simulator.
https://www.ebikes.ca/tools/simulat...C&cont=C25&grade=10&axis=mph&wheel=28i&hp=100

He says it will overheat on a 10' grade after 12 minutes. If he sez so.

Ok, I am a college graduate but i avoided science and math classes like the plague. So you'll have to excuse my ignorance. It looks like it assumes 100 watts of human power. Is that average? 12 minutes sounds really quick. Can anyone speak to how accurate this is in the real world?