Are newer hub motors as capable as mid drives?

[Gordon71]

How steep and how long are your hills? That matters a bit.

Some are pretty steep but not particularly long.

 

[m@Robertson]

I HIGHLY doubt any bike, middrive or hub is hauling 400lbs up a 10% grade at 12mph throttle only.

I am, although I do it purely with pedal power. I put the front pedal assist at 3 of 5 because I don't want to break anything. My rear motor gearing is 40T chainring and the 34T rear cog. I stay away from the 40 and 48 because of skewed chainline on a bike with very short stays. I do max out the assist level on my BBSHD in the back but I have my motor de-tuned on pedal assist so it is putting out about 850-950w continuously. My display peaks at 1000 so I know I have more in it if I was willing to hit that throttle and take it to its roughly 1700w peak. But I build bikes to use that keep working so I have no interest in creating a failure by overdoing the power.

You are seeing 100 lbs of gravel. I weigh 250 lbs. 250+100=350. Add in my locking mech at about 20 lbs, and then the bike itself and I am well over 400 lbs. Probably around 450 when you tally in bike, battery and motor. Its only rated for 400 but the engineers @ LvH say the platform hits its weight limit at the wheels and I have had extra strong ones built, with oversized tires. Route is from Home Depot in Marina CA to lets say Trader Joe's in Pacific Grove CA. Use the climb up Prescott Ave. for reference. I actually live a bit down over the top of that hill, not at its peak, but I still have to get over it.

If I was willing to use throttle I could exceed the 12 mph, or if I forget to use the right 34T rear cog and stay in my 28T, I can get up to 14-16, but its really dumb to stress the drivetrain like that and I try to make sure am aware of my gears before I start my climb so I don't make that mistake. I have a front motor which makes this possible, but I could do the same load with my Surly which was rear-motor-only, but of course slower (36T front ring and IIRC 40T rear). Probably 8 mph and I was working pretty hard to get it up that high. The consequences for stopping mid-hill are failure to restart so you pedal hard with force to make sure you make it up.

Saying that a hub motor can make climbs even remotely approaching this is coming from people who don't ride the bike hard enough to know better. There's no nice way to say that.

The tests I recently saw on the new Lectric cargo bike are laudable as it is a single hub motor that can get up LA's Eldred St. grade, but if you think a little critically, you see the rider is puffing hard to grunt/assist/inch his way up, and much more importantly, he has no cargo. It is an achievement for a hub motor to get up that hill at all, but it is a stunt and not a measure of actual utility.

 

[linklemming]

Also, the hub-drive motor needs to have far more power to match the mid-drive performance, especially on climbing.

This comparison at grin seems to contradict your claim
https://ebikes.ca/tools/simulator.h...throt_b=100&autothrot_b=false&autothrot=false

With this gearing and speed, the BBSHD requires the rider to ride at 130rpm cadence, going to a slower cadence(90rpm) doesnt make the BBSHD any better than the GMAC.

No doubt the mid-drive is better for climbing (which is why I own several) but thats not the whole story

I ride a geared hub drive(GMAC 10t)/mid-drive(BBSHD).DD(RH212) on the same rides every day switching between the bikes every ride (I also have several Brose mid drives including a specialized). They all have their strengths and weaknesses

 

[Mr. Coffee]

Some are pretty steep but not particularly long.

Well, my experience is that it is a very rare hub drive that can push any bike and any rider up a ten percent grade much longer than a mile. If the road is rougher or has sharp switchbacks that make it necessary to slow down that makes it harder still.

 

[linklemming]

Well, my experience is that it is a very rare hub drive that can push any bike and any rider up a ten percent grade much longer than a mile. If the road is rougher or has sharp switchbacks that make it necessary to slow down that makes it harder still.

I would agree with that both from experience and using the grin motor simulator.

Sure the geared hub drive can go up steep hills, just not for long. I did an exhausting analysis on the grin simulator a few years back and the GMAC10t would start overheating at anything over 6% (at full power). I can do longer 10% climbs just fine as long as I keep the power lower (about 500 watts)

 

[m@Robertson]

Yeah as respected as the Grin simulator is, if its saying a hub drive is in any way in the league of a mid drive going up hills with a load, there is a variable somewhere that isn't being plugged in. This is one of those things you figure out real fast in real life, on the bike. I abandoned a twin-hub 2wd bike that on paper has 80 nm per axle, twin 35a controllers and a battery well-capable of handling the peak and continuous loads. It was obvious listening to those poor motors groan up a hill (literally, you could hear them laboring) that a bike that was able to live forever and barely warm up on flat ground was out of its league when you take it hill climbing and give it a job. I didn't spend that kind of money on a bike to kill it prematurely when it can liver forever and haul ass in terrain suited for it.

My next move was my first 2wd build with a mid drive in the back and the superiority of its performance made it obvious I was done building bikes with hub drives as primary power.

 

[m@Robertson]

I haven't run these in awhile, and unfortunately, the Grin simulator will not let you use the BBSHD's built in controller for some reason. But picking matching cold Baserunner controllers - you can use one on a BBSHD - and using the Bafang bigfoot 750 as the hub to compare it to, I ran simulations on a 10% grade with 400 lb, 308 lb and a bantamweight 220 lb load. Then I plugged in my own 40T/34T preferred gearing. I used an 80% efficiency rating simply because the G060 has 80% efficiency and I was looking to eliminate that as a variable, but I think the BBSHD has a better efficiency value and these results should improve a bit. I don't see a place to plug in cadence so just tossed it on 100% throttle with 100w added for human power. It pretty much shows what you expect. The hub motor can boil water and overheats. The BBSHD never does (the Advanced options are shown but I did not use them).

In fairness, you aren't going to be going up too many hills that are 7-10 miles long, but that ">250 degrees celsius" temperature is going to have consequences on the nylon planetary gears long before it gets to 250.

I ran it using the GMAC 10T and surprisingly got worse results. For something like my own bike the GMAC would be the real option since mine is not a fat bike.

 

[gromike]

Maybe it's because all my steep hills are short, but I really love riding my DD hub motor bike. The motor is next to silent.

I installed a suspension fork on my mid-drive bike today and went for a spin. Yeah, that thing does rock it up the hills. Though, without rear suspension, it's kinda like riding a hardtail Harley.

 

[linklemming]

I haven't run these in awhile, and unfortunately, the Grin simulator will not let you use the BBSHD's built in controller for some reason. But picking matching cold Baserunner controllers - you can use one on a BBSHD - and using the Bafang bigfoot 750 as the hub to compare it to, I ran simulations on a 10% grade with 400 lb, 308 lb and a bantamweight 220 lb load. Then I plugged in my own 40T/34T preferred gearing. I used an 80% efficiency rating simply because the G060 has 80% efficiency and I was looking to eliminate that as a variable, but I think the BBSHD has a better efficiency value and these results should improve a bit. I don't see a place to plug in cadence so just tossed it on 100% throttle with 100w added for human power. It pretty much shows what you expect. The hub motor can boil water and overheats. The BBSHD never does (the Advanced options are shown but I did not use them).

In fairness, you aren't going to be going up too many hills that are 7-10 miles long, but that ">250 degrees celsius" temperature is going to have consequences on the nylon planetary gears long before it gets to 250.

I ran it using the GMAC 10T and surprisingly got worse results. For something like my own bike the GMAC would be the real option since mine is not a fat bike.

Isnt the grin motor simulator fun. You can also play with I think their trip analyzer and use actual terrain data.

Lots of variables to play with (lots of videos on how to use).

Justin also gave some good insights to his BBS02/BBSHD testing and incorporation into the tool on endless-sphere
https://endless-sphere.com/forums/viewtopic.php?f=2&t=100461

For the grade/load you have as an example(at full throttle), no doubt the BBSHD is the better bet. For my more casual rides, the GMAC and BBSHD are basically identical with the GMAC being better at higher speeds/and loads (20mph+, rolling hills with strong headwinds) and the BBSHD being better in the hills (although most of mine are short enough(less than a mile) to not really have a difference). For strictly offroad (i.e. MTBing) its Brose all the way.

 

[linklemming]

Maybe it's because all my steep hills are short, but I really love riding my DD hub motor bike. The motor is next to silent.

I installed a suspension fork on my mid-drive bike today and went for a spin. Yeah, that thing does rock it up the hills. Though, without rear suspension, it's kinda like riding a hardtail Harley.

I love the silence of my RH212 as well.

It definately is a dog below 15mph and starting from a stop. Hills take quite a bit more power (i.e. 0% to 6% I go from a constant 300W to 600W. I can also use my legs).

All that matters is that you like it

The hub vs mid-drive debate will never end (usually heavily debated by those who only have one or the other)

 

[MinnBobber]

Pardon my ignorance but do any of the comparison charts show a Rear Hub Direct Drive motor??

IMO, the rear hub Geared can be great for short steep climbs but long steep climbs overheat it..

The rear hub direct drive is the coolest running motor, with no reduction gears/belts/etc.
It is a bigger motor with more magnets and ability to take big current without overheating.

Just my experience, but a direct drive + me going all in …a hill has never stalled me.
And , after a hilly ride on a 95 F day, the motor is barely warm to the touch.

I have probably only ridden .000005% of my miles on 20% grades so don’t need a mid drive with granny gear for my use.

A hub motor is not like a car with a one speed tranny.
It is like a one speed tranny electromotive freight train that pulls hundreds of tons of cargo with electric motors. And it also climbs a few hills.

Ride what you enjoy!

 

[ElevenAD]

The vid is based on a very short 20% grade segment. I wonder what would have happened to any of those motors on a 4 mile climb of the average grade 5.7% with long segments of 8.6 or 10.4% grade (that was something I had to climb on a 520 W peak power mid-motor e-bike with a 21.4 gear-inches granny gear).

I took my hub bike on a run with similar condition only once, the bike is 750watt nominal and peaks at just under 1000watts and even with generous rider input this is not something i would do again, i felt it was just to much motor stress. In my experience you cant beat a middrive for climbing.

 

[m@Robertson]

Just my experience, but a direct drive + me going all in …a hill has never stalled me.
And , after a hilly ride on a 95 F day, the motor is barely warm to the touch.

The issue with a direct drive hub is it has the lowest available torque of all of the motor types. You overcome this with increased size. Throw on something like a QS 205 v3 and you can climb anything and take off like a bat out of hell. Its a 3000w-rated motor that can go to 5000w if you want to take it there. But a big hub to overcome that low torque a lot of weight, and the battery needed to push it up to higher performance is going to be big too. Generally if you take a DD hub to this level it creates more of a light motorcycle than it does a bicycle. Thats where you usually see big, powerful hubs used.

But its also a maintenance-free solution which certainly counts for something.

With a mid, there's no need to go all in as you say. You can still pick your exertion level. In those 400+ lb loads I was mentioning, I still can back off of the pedal assist if I need to and hit the throttle to crank up the boost.

Every motor type has its ideal use case. None of them are ideal for everything.

 

[tomjasz]

Grin simulator will not let you use the BBSHD's built in controller

Custom controller settings?

 

[PedalUma]

Over the weekend I had to deliver a Bafang 750W geared hub drive that is a 20" fat folder. I replaced the motor core earlier in the day. After 5 miles of mostly flats it took a dump on the final hill with thermal shut down. Hot to the touch. That would never happen with one of my 350W mid-drives. I have done extended 12% grades with them.

 

[AHicks]

Over the weekend I had to deliver a Bafang 750W geared hub drive that is a 20" fat folder. I replaced the motor core earlier in the day. After 5 miles of mostly flats it took a dump on the final hill with thermal shut down. Hot to the touch. That would never happen with one of my 350W mid-drives. I have done extended 12% grades with them.

Too much throttle and not enough pedaling maybe?

 

[PedalUma]

Exactly. You got it @AHicks. The thing is 100 pounds with 20" wheels and knobby low pressure tires. Also, the PAS sensor was bad. I just got the replacement and will ride it back to my workshop in about 40 minutes. It is so funny how many people are proud fat folder owners. It is like a guy who thinks his mom is the best cook in the whole world but has never eaten anywhere else like Singapore.

 

[linklemming]

Pardon my ignorance but do any of the comparison charts show a Rear Hub Direct Drive motor??

IMO, the rear hub Geared can be great for short steep climbs but long steep climbs overheat it..

The rear hub direct drive is the coolest running motor, with no reduction gears/belts/etc.
It is a bigger motor with more magnets and ability to take big current without overheating.

Just my experience, but a direct drive + me going all in …a hill has never stalled me.
And , after a hilly ride on a 95 F day, the motor is barely warm to the touch.

I have probably only ridden .000005% of my miles on 20% grades so don’t need a mid drive with granny gear for my use.

A hub motor is not like a car with a one speed tranny.
It is like a one speed tranny electromotive freight train that pulls hundreds of tons of cargo with electric motors. And it also climbs a few hills.

Ride what you enjoy!

Here is one using a RH212(DD) with statorade compared to a GMAC 10T(geared hub)
https://ebikes.ca/tools/simulator.h...b=29i&mass_b=140&bopen=true&grade=9&grade_b=9

The DD starts to overheat over 9% grade, the GMAC much sooner.

I recenty started riding a RH212 with statorade in addition to a BBSHD and GMAC 10T, The RH212 stays cool ALL the time. Most average rides its below 50C the whole ride (typically 25 miles, about 1300ft elevation, usually average 16-20mph, high power section at the end on rolling 4-6% hills, some about a mile long, headwind usually 15mph+, about 6 miles). Worst I have ever seen it was 72C and that was 100% throttle on this high power section (I dont typically ride this way, just wanted a worst case).

Note that if you use a controller which has temp sensing and ability to limit power (like the Grin Phaserunner/CA3), it starts cutting power at 90C. Who knows what the upper limit is...highest I have ever seen was 110C on the GMAC and that was limping home on a motor that had partially seized bearings.

All that being said, my BBSHD is without a doubt the 'most versatile'. It does have limits at the upper end of mph and power (its max rpm(cadence) with 52V and 28mph or so is about 140, when brought down to a more realistic 90rpm, it isnt as efficient)..basically it becomnes a contradiction as to whether the rider should supply power for best performance.

 

[m@Robertson]

All that being said, my BBSHD is without a doubt the 'most versatile'.

Thats what I have found as well. Its not perfect but its reasonably effective for the widest range of use cases, and best of breed in one of them. I've also found that thinking through a build and then riding it smart eliminates the negatives you hear with regard to wear and tear. Net result has been I just stopped trying to work in alternatives as what I've got works and doesn't break.

 

[linklemming]

Thats what I have found as well. Its not perfect but its reasonably effective for the widest range of use cases, and best of breed in one of them. I've also found that thinking through a build and then riding it smart eliminates the negatives you hear with regard to wear and tear. Net result has been I just stopped trying to work in alternatives as what I've got works and doesn't break.

Definately agree....its also the most fun to ride, not sure why that is..perhaps lowest cg. If it had torque sensing thats all I would own.

I have high hopes for the CYC proton

I did do a 6 month stint on just the BBSHD (on both DIY ebikes). When I went back to the GMAC with torque sensing it was such a nice change. WIth the BBSHD, you just dont go much faster when pushing harder so you tend not to. The rush of more electric power when you push harder on a torque sensing system inspires me to workout harder.

Note that my rides are all for fitness. Commuter and/or sightseeing types might prefer cadence sensing more