Mid Drive vs Hub Drive Electric Bikes?

["A"]

Even when it comes to life & death in combat zone.. mid-drive or hub-drive?

British soldiers may adopt electric bikes fitted with rocket launchers

British soldiers may be getting a new type of military vehicle, only this time it will come with just two...

electrek.co

 

[neutron]

I need one of those for the bike trail on weekends!

 

[hsdrggr]

Since someone inquired about the hub in my fat bike build, referencing the Nuvinci N171 CVP hub’s ability to climb hills. I’ll post it’s ratio specs. It has a 350% ratio range (0.5 Under-Drive to 1.75 Over-Drive) So on my bike it’s similar to a 11-38 cassette. I’m running a 42T front chainring on the BBSHD and 22T rear track cog. It climb’s serious grades extremely well. It’s low end ratio is actually a little too low in this configuration for pedaling; the cadence is too fast for me to even match it. However where it shines is in its torque/climbing ability under throttle. I made this bike as a fun bike, for beach, off road hilly terrain and for general goofing around. It only has a 10.4ah battery because I don’t really care about distance. I have another e-bike for that. However I have found that I really like it for short trips on the road with my wife on weekend jaunts to restaurants, concerts, and to the beach. These rides are about 25 miles max round trip and battery is more than capable for that.

 

[CrossRoads]

I would put mid-drive in the middle of a hierarchic list of increasing speed / power / performance / price as follows:

1: Super simple, inexpensive, easy to install, easy to maintain e-bike that will get you to the grocery store and back at 25 - 27 mph, you want a geared rear hub motor 500- 750 watts. Kits start as low as $600.

2: More power, better climbing efficiency, better top-end speed (35 mph) better over-all performance, you want a mid-drive, 750-1000 watts (bbs02 or bbshd). Also higher price tag. Kits start at $1100. Plan on replacing your chain and cassette often, but that's not too expensive if you keep it to an 8 speed drive-train.

3: Getting into "basically almost a motorcycle" territory, putting over 1500 watts into a traditional bike chain will tear it to shreds, so you need to go back to hub motor. You really want a direct drive hub motor for the better speed and you probably want higher voltage (60v to 72v) and you might even want to do dual-hub motors for more power and redundancy. You can also do regenerative breaking with a direct drive hub motor. You're into a cutting-edge creative and new category that is honestly beyond e-bike and hedging into electric-vehicle territory. 45mph + speeds and 100 mile ranges are possible but plan to spend more money.

 

[hugh]

I know this an old thread but heres my 2 cents worth anyway. I have both types of motors and like them both. My fatbike with the BBSHD is used mostly for trailriding and it works well. The home built delta trike uses a 500 watt geared front hub motor and used with it's 58 tooth chainring effectively has 2wd and it also works well and is used primarily for trips around the city from 60 to 80 km's in length. I just finished a 2nd delta and it has a BBS02 mid drive. That one I'm just waiting for the snow and ice to go before testing and debugging.

 

[biknut]

Unless you live at the top of a mountain, and need to ride home every night, get a hubby. Mid drives are very hard on bicycle drive train components, and will be a source of constant maintenance. The difference in reliability is like comparing an anvil to a Yugoslavian washing machine.

 

[m@Robertson]

Nah. Thats just not true. Mid drives with maintenance issues were built wrong or the rider caused the problem and blamed the equipment.

My "constant maintenance" is lubing my chain every few weeks. Nothing else. I put 2000 miles on my main daily bike last year and it still has the original chain, chainring and rear cluster. Thats a bike that carries 100 lb loads regularly, in addition to my 235 lb self. My Surly Big Fat Dummy with a 210-link chain is at 1500 miles and same deal. Original chain/cluster and nothing broken. I am far from unique in this kind of result.

I have both types of motors and like them both.

Same here. Mid drives may have a wider range of use (they can go places hub motors cannot) but the most fun I had with an ebike (and the most mileage I've ever put on a single bike as a commuter) was one with a geared hub motor (actually it had two of them). Each has its advantages and disadvantages. I started building mid drives when my hub motor bikes hit the proverbial wall when I started having to live with hills.

Speaking of which, an objective demonstration versus having to listen to preaching fanatics would be useful for anyone who wants to learn and judge for themselves. Since this thread came and went, I came across an outstanding illustration of geared hub motor performance in hills. The Youtuber who did it made the test repeatable, tested only the bike (throttle only) and repeated the test with 14 different direct-to-consumer bikes. Big wheels, small wheels, varying motor power up to 1000w and a variety of battery voltages. This is what you get with a geared hub motor in hills.

 

[addertooth]

Yes, I agree with much of what was said above, let me add.....

With a hub motor, you will make it home even if:
1. Your Chain breaks.
2. Your rear cog strips.
3. Your derailer fails, or gets smashed.
4. Your derailer cable breaks, and you are stuck in top gear.

 

[hugh]

I now own 3 Bafang mid drive bikes. The fat bike has roughly 4,000 miles on it's drivetrain in the 9 years of using it. In that time it has needed the freehub replaced once and has had it's chain replaced once as well. The chain was not worn out and I keep it in my small backpack as a spare. It was used once when the master link broke while powering up a rocky hill.
One of my past delta's used a Magic Pie direct drive rear hub motor. That unit failed, it's still waiting for a teardown but I suspect some of the internal magnets came loose. That made it impossible to pedal and my wife had to pick it and me up in the truck. Prior to that the motor was a lot of fun and pretty fast as well. I also has a Bion X rear hub which was nice but taught me to never want to buy another brand where you have to buy only their battery.
Having said that I really like the geared front 500 watt motor on one of my Delta's. It gives the best of both world's when used on our roads which are mainly flat since Winnipeg is on the edge of the Canadian prairies. Pedal power is me and the front wheel is powered so it should be very dependable

 

[m@Robertson]

Yes, I agree with much of what was said above, let me add.....

With a hub motor, you will make it home even if:
1. Your Chain breaks.

I have never broken a chain across I think 8 mid drive bikes that are subject to pretty extreme use. BUT I also carry an entire spare chain. Its in its original package so its very compact. Also a mini chainbreaker and a couple of spare quicklinks, so even though I have never used it, a broken chain is not a showstopper. This is an extreme but as a rider who has to depend on his bike daily I have learned to trade a bit of weight for certainty. Less committed riders just carry a chainbreaker to shorten a chain if it breaks. You can always get home on a single gear.

Doesn't have to be one of my behemoth cargo bikes to make this practical. My little Apostate has chain and all tools in the back pouch. Its a tubeless setup but you see I still have a tube strapped on back there. I believe in redundant backups across the board whether I need them or not.

2. Your rear cog strips.

I have never seen this happen. If you mean strip as in the threads below the cog, only hub motor bikes should be forced to use freewheels. Cassettes don't have threaded cogs. Freewheels went the way of the dinosaur in favor of cassettes until Cheap Far East ebikes revived their use. If you mean stripping the actual teeth off a cog, never seen it happen. I cracked an 11T cog once but it held together fine and I only found it on a postflight inspection. A $7 item. BUT that was an alloy cog used before I found steel cassettes. Nowadays that can't happen with a $35-$45 Microshift cassette that has all steel cogs right down to the 11T mini.

But as I've said earlier, to get an absolutely bulletproof mid drive you have to think thru your build and pick parts that don't break. People break things because they don't know enough to make the right choices but build it anyway with the wrong parts.

This freewheel failed on one of my hub motor bikes (My steel-frame Sondors, in 2017). It split apart less than 2 miles from home and froze the rear wheel solid when it came apart. I had to carry it home. But that is not the fault of the hub motor and I can't blame hub motor ebikes for the component failure. A hub bike can go down just as hard from a drivetrain failure.

3. Your derailer fails, or gets smashed.

True of any bike including hub motor bikes. Since the derailleur is on the return side of the drivetrain, it is not subject to the torque a mid drive applies. So if you smash into a rock going downhill on any bike or ebike, you are walking. Now, the hub motor can keep going so long as the freewheel is not damaged. Granted. But think for a minute whether this is a real benefit: For many decades just plain bicycles were around and they ALL suffered from this potential for disablement, and still do. It didn't stop anyone from riding bikes, right? Or buying bikes with derailleurs either.

4. Your derailer cable breaks, and you are stuck in top gear.

Every bike ever built with a derailleur has the same potential. Derailleur cables are under no duress from a mid drive. So this is a reason for not riding any bicycle if you concede it as a real thing to worry about. It DOES give a hub motor bike an extra fail-safe, but not much of a real-world risk. And even in the lowest gear you can still ride home just fine. Just slower.

 

[Ghill]

I see that it is a single speed, doesn't really take advantage of the drivetrain gearing for hills that mid-drive is known for.
Have you tested its hill climbing ability?

 

[munirider]

Good video. The hill from town to our house climbs 1,800 feet in six miles an average of almost 6% with sections of 9% grade, from 6,985 to 8,800 ft.. I have a neighbor who tried to ride his Matte folding bike with 20" wheels up it and fried his motor before he was 1/2 way up.

Our mid drive bikes make it up without any problem, with either BBSO2 or BBSHD motors and 26" wheels.

Living where I live I have no interest in hub motors.

 

[Calsun]

My bike has a mid-drive motor and I can turn it off to provide zero pedal assist with no issues. My first e-bike had a hub drive as these are cheaper to make but I dreaded having a flat tire and having to remove the rear wheel. My Class III bike with the mid-drive is exactly like my regular road bikes in terms of its tires.

It comes down to how much you want to pay for your e-bike. I wanted as natural a ride with adjustable pedal assistance and smooth transitions in the assistance at speeds up to 25 mph and few e-bikes provide that.