Motor decision for long john cargo bike w/ steep hills

[Chalo]

Also, I'm very aware of my IGH torque limitations and gear ratio needs. I'm not experienced with the motors I've been asking about, but I'm plenty experienced with bicycle drivetrains and using them for cargo applications.

BBSHD's maximum torque is 160Nm, so you can add that to your estimated pedal torque. Then divide by your external gear ratio to get input torque for your hub.

 

[qwerkus]

What I mean is that I know what my chainline requirements are, and what the resulting chainlines are from the various motor chainrings, so I'm not worried about it. Also, I'm very aware of my IGH torque limitations and gear ratio needs. I'm not experienced with the motors I've been asking about, but I'm plenty experienced with bicycle drivetrains and using them for cargo applications.

Check this out: https://www.endless-sphere.com/forums/viewtopic.php?f=28&t=16264&start=100#p1464217 and this https://www.electricbike.com/mid-drive-kit-igh/

I've been riding ighs for years too before building my first ebike, and it was a though landing: you cannot base your motorized expectations on your un-motorized experience. Power level are just a magnitude higher. There is quite some discussion here about which igh can handle how much power, and besides super strong 3 speed hubs, plus that one sachs p5 cargo hub and perhaps the old nuvinci, none is built to withstand the power of bbshd, or a 1kw unleashed 02. There is not much feedback about the new nexus 5 speed, but I don't expect miracles from it, as it's targetting the european market where 250w is the limit.

Anyway, it seems to me your mind is set on the drivetrain, and you'll have to make you're own experiences. Let's see where this goes - Keep us posted!

 

[Nightdiver13]

Check this out: https://www.endless-sphere.com/forums/viewtopic.php?f=28&t=16264&start=100#p1464217 and this https://www.electricbike.com/mid-drive-kit-igh/

I've been riding ighs for years too before building my first ebike, and it was a though landing: you cannot base your motorized expectations on your un-motorized experience. Power level are just a magnitude higher. There is quite some discussion here about which igh can handle how much power, and besides super strong 3 speed hubs, plus that one sachs p5 cargo hub and perhaps the old nuvinci, none is built to withstand the power of bbshd, or a 1kw unleashed 02. There is not much feedback about the new nexus 5 speed, but I don't expect miracles from it, as it's targetting the european market where 250w is the limit.

Anyway, it seems to me your mind is set on the drivetrain, and you'll have to make you're own experiences. Let's see where this goes - Keep us posted!

I really do appreciate all the feedback and I know all the extra advice is intended to be helpful as there are a lot of people who do crazy/stupid things with bikes. But my experience does extend into motorized applications as well. I work for a bicycle manufacturer who produces electric cargo bikes and as such am involved in loads of product testing as well as discussions with product managers from all the major manufactures (Rohloff, Enviolo, Shimano, etc).

All this experience has been limited to Bosch and Bafang integrated motor systems. Now with this long-john project I am forced to use an aftermarket kit. I realize that the BBSxx is capable of higher inputs, however I don't necessarily plan to use all that extra input and if I do, am doing so with the understanding of the consequences. This was one factor in making me consider the hub motor options.

 

[Nightdiver13]

I'm late to this thread, but I recommend buying a BBSHD while they are still being produced. 52V battery.

The stock sprocket has 46 teeth, so get something with fewer teeth. I believe there are 30T-36T sprockets and a 2-piece chainring/spider set with 40T (steel teeth/aluminum spider)

I missed your post originally. Thanks for the input. Mind me asking... if I plan on rarely using the full output from the BBS02, would you still recommend the HD instead? I have read about the design being an improvement in several ways, but then have read conflicting opinions (such as qwerkus in this thread). What is the reason for going HD over 02? What is this about "still being produced"?

 

[spinningmagnets]

BBSHD uses Interior Permanent Magnet/ IPM configuration, BBS02 is not only slightly smaller, it uses surface mount magnets. This protects the magnets from heat-spikes and eddy current waste-heat. Under the same exact loads, the BBSHD will run cooler than the BBS02. Nothing wrong with the TSDZ2 or BBS02, but you mention steep roads and heavy cargo.

I have no proof, but I'm hearing rumors the BBSHD might be discontinued because Bafang is doing quite well with their factory proprietary drives, which the majority of the public definitely prefers. Drives like the Bafang Ultra Max and M600

https://endless-sphere.com/forums/viewtopic.php?t=100777

https://www.electricbike.com/bafang-ultra-max/

 

[kevinscargobike]

This is a super interesting thread for me. I live at the top of a 200ft climb that has a couple of sections of 15-20%. My family has two long johns, a Packster 80 (Bosch obvs) and my Cetma using a front Mac hub motor with a Phaserunner at 52v.

My Cetma came with a Stokemonkey, and it may have been set up slightly wrong, but I couldn’t keep up with the Bosch Packster using it. I used a Tsdz2 on a Boda Boda, and I wouldn’t try to do heavy cargo hill climbing with it.

My plan had been to do dual motor, but since I found a used bike with a belt and IGH, I decided to see how well I did with the single motor. The Mac up front is worlds better on the climb in every scenario other than if I have 200lbs of cargo and I’m on the very steepest part.

What I grew to appreciate about the hub motor from a bikey POV is that I really liked that the bike drivetrain is just for me and I never have to shift because the motor needs it. I also found that I really liked the combo of torque sensing and infinite assist adjustment with the infinite gearing on the nuvinci.

I have hit thermal limits for the motor and controller, which makes me a little nervous for you with the longer climb, but honestly, I feel there’s no great solution. The torque needed from a mid drive isn’t necessarily super compatible with a bike drivetrain, and it’s hard to get enough torque or thermal breathing room from a single hub motor.

One piece of advice I can add is that high power batteries do a much better job of getting you home at the end of the trip.

I recently bought a silly super heavy 700lb capacity bike trailer and found that I can barely get it up my hill when it’s empty, which has me thinking about adding that second motor after all. I might throw the Stokemonkey back on, because I have it, or I might give up my beautiful belt drive to add a GMAC, but even if I do, it’s after putting 6500 miles on with just the front Mac.

btw, which long john do you have?

 

[Jil]

Very intersting thread ! I have indeed the same kind of question.
--> I'm thinking about building a long-john cargo bike (26" rear, 20" front), suitable for heavy-duty professional use (heavy loads -up to 150kg payload- and high daily mileage).

For having tried mid-drive motor (BBS01 48V) on my Surly Krampus, the wear of the transmission was already problematic depiste good-quality components. I cannot imagine with a cargo bike and a BBSHD. Perhaps with a Rolhoff + belt (the kind of setup found on high-end Riese&Muller cargo bikes) ? In addition, with a mid-drive there is no regen braking and I guess the wear of brake pads on a cargo bike must be quite huge.

I currently have a GMAC on my ebike, which I like. But for a cargo bike I prefer the idea of front direct drive motor : 2 wheels drive (muscular rear, electrical front), 20" wheel well-suited for hub motors, no maintenance apart from bearings replacement from time to time. And this also :

What I grew to appreciate about the hub motor from a bikey POV is that I really liked that the bike drivetrain is just for me and I never have to shift because the motor needs it.

What would be the best setup ? Frankrunner/Phaserunner for the controller, but I'm hesitating between the Grin All-Axle and the RH212 (or else ?)

On 25% grade with 500 lbs all-in and 300 watts peak pedaling power, the RH212 is slightly more efficient :
https://ebikes.ca/tools/simulator.html?motor=MGRIN_STD_SA&batt=B4816_GA&cont=FR&wheel=20i&mass=227&grade=25&hp=300&cont_b=FR&motor_b=9C212_7.5T_SA&batt_b=B4816_GA&wheel_b=20i&mass_b=227&hp_b=300&grade_b=25&bopen=true
And the BBSHD is more efficient than the RH212 (but it overheats as quickly) :
https://ebikes.ca/tools/simulator.html?motor=9C212_7.5T_SA&batt=B4816_GA&cont=FR&wheel=20i&mass=227&grade=25&hp=300&cont_b=FR&motor_b=MBBSHD&batt_b=B4816_GA&wheel_b=20i&mass_b=227&hp_b=300&grade_b=25&bopen=true&autothrot_b=false&autothrot=false&throt=100&throt_b=100&mid_b=true&gear_b=1&tf_b=42&tr_b=30

On 7% grade @100 watts pedaling power, the RH212 is also slightly more efficient:
https://ebikes.ca/tools/simulator.html?motor=MGRIN_STD_SA&batt=B4816_GA&cont=FR&wheel=20i&mass=227&grade=7&hp=100&cont_b=FR&motor_b=9C212_7.5T_SA&batt_b=B4816_GA&wheel_b=20i&mass_b=227&hp_b=100&grade_b=7&bopen=true&autothrot_b=false&autothrot=false&throt=44&throt_b=36.7

On flat terrain, the Grin has a better efficiency :
https://ebikes.ca/tools/simulator.html?motor=MGRIN_STD_SA&batt=B4816_GA&cont=FR&wheel=20i&mass=227&grade=0&hp=100&cont_b=FR&motor_b=9C212_7.5T_SA&batt_b=B4816_GA&wheel_b=20i&mass_b=227&hp_b=100&grade_b=0&bopen=true&autothrot_b=true&autothrot=true&throt=6.8361606833450805&throt_b=5.994712603576505

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I would be inclined to choose the Grin, because it is all-axles compatible (I'm not found of the standard axle setup (i.e. not thru-axle) for hub motors, it damages the dropouts and is not as clean as a thru-axle setup), and it's made by Grin in Canada.
Your thoughts ?

Another question : on wet roads and driving an empty cargo bike, can the front hub motor be more difficult to handle than a rear hub or mid drive in terms of grip ?

 

[Jil]

There is not much feedback about the new nexus 5 speed, but I don't expect miracles from it, as it's targetting the european market where 250w is the limit.

Remember that this limit is nominal power, not peak power. In real-life, many mid-drive motors have maximum outputs above 500 watts (but manufacturers communicate only on peak torques, not peak powers).

 

[kevinscargobike]

I’ve only had a bad motor spinout on my front wheel once, I was riding on this wet wooden bridge and I turned the wheel and accelerated at the same time and the bike went sideways under me and then slid like 20 feet.

My ideal is probably GMAC in the back, all axle in the front (mostly for the nice torque arms) and a belt drive with a pinion gearbox that magically also has torque sensing. Maybe if they existed, I’d do GMAC in the front combined with a torque sensing DD in the rear? (My secret suspicion is that the upcoming rear all axle will have torque sensing)

I briefly had a Bionx and front Mac on my old Yuba Mundo at the same time and I wish I’d played with it longer because it was so awesome having all of that torque, so on any bike that has a derailleur anyway, dual motors seems so appealing.

 

[Phasedout]

My lwb recumbent, loaded up for travelling,.weighs about 350 odd pounds. I had a Mac as a midrive, and could climb walls, but grew tired shifting, and fussing.
A 3540 in a 20" wheel, has been perfect, in this gently rolling countryside, but I sure wouldn't want to stop on a steep, or even semi steep, hill.
A Mac 10t in the same wheel, was also excellent, but slow, and hot.
The simplest, most reliable, and most expensive solution, is a slow, fat hub, with many amps, and, a big, powerful battery.

 

[qwerkus]

There is not much feedback about the new nexus 5 speed, but I don't expect miracles from it, as it's targetting the european market where 250w is the limit.

Remember that this limit is nominal power, not peak power. In real-life, many mid-drive motors have maximum outputs above 500 watts (but manufacturers communicate only on peak torques, not peak powers).

Yes I'm aware of that. Someone on the german forum measured 800w during startup on a bosh cx. And that was with a "250W motor". The legislation is somewhat obscure there, since motor power is supposed to stay below 250w on average over a fixed period of time (iirc 15min?). Overall, my experience is that nobody cares. Speed limitation of 25km/h is much more important.

Check the link I posted with shimano limitations: 500w is the given upper limit. I broke my hub at around 900w.

 

[Chalo]

Someone on the german forum measured 800w during startup on a bosh cx. And that was with a "250W motor". The legislation is somewhat obscure there, since motor power is supposed to stay below 250w on average over a fixed period of time (iirc 15min?). Overall, my experience is that nobody cares. Speed limitation of 25km/h is much more important.

Check the link I posted with shimano limitations: 500w is the given upper limit. I broke my hub at around 900w.

It's not power that breaks internal gear hubs, it's torque. Doubling power by doubling RPM has no negative effect on them.

In this use case (high mass, steep slopes), input torque limits are a factor even with a low powered motor, or no motor. Exceed them at your own risk.

 

[qwerkus]

Finally had some time to take a pic. Batteries are under the front half of the loading space. Box is hommade 70x70cm. Kids-seats are from a swiss trailer maker (leggero). By far the best seats i ve seen.

 

[Nightdiver13]

btw, which long john do you have?

Same one as you. I messaged you back when I was starting this whole process after I came across your build thread. You can see I've made a lot of progress...

 

[Nightdiver13]

Finally had some time to take a pic. Batteries are under the front half of the loading space. Box is hommade 70x70cm. Kids-seats are from a swiss trailer maker (leggero). By far the best seats i ve seen.

Oohh... very nice. That box build is great looking. Do you have a thread detailing that? I've seen that frame used by a few different "brands" but never seen one used by a real person. How is it treating you?

 

[qwerkus]

Oohh... very nice. That box build is great looking. Do you have a thread detailing that? I've seen that frame used by a few different "brands" but never seen one used by a real person. How is it treating you?

No, sadly I didn t document the process of building that box. It s phenol wax pre treated wood pannels (9mm sides and 12mm bottom) screwed and glued together. Aluminium reinforcement are bolted on the sides and glued on top. As mentioned, the best parts are the seats: super smart design - takes 1min to mount/umoun them out if required - and they protect the kids neck.

That frame is so-so. Cheap copy of a bullit. If properly re-designed, one could easily make it 10-15cm shorter. The turning radius is awful, but the main reasons I got it were the possibility to fit wide tires (up to 2.5"), clean chain tensioner (sliding dropouts) and above all the two parts design which allows you to disassemble and transport it in the back of a large car. Also the aluminium is overbuild: heavy but sturdy. And finally, price was very good at the time. Now it s also super expensive.

In hindsight, the sliding dropouts were not a smart choice. Looks clean but it's not designed for heavy loads. I keep re-adjusting them after wide temperature and load changes. Sturdy vert dropouts would work better; the weight of a chain tensioner on that system is negligible.

 

[Jil]

Finally had some time to take a pic. Batteries are under the front half of the loading space. Box is hommade 70x70cm. Kids-seats are from a swiss trailer maker (leggero). By far the best seats i ve seen.

1.png

Beautiful bike :thumb:
What is the frame ?
And what is the controller/battery you've paired to this FH212 front motor ?

 

[qwerkus]

What is the frame ?
And what is the controller/battery you've paired to this FH212 front motor ?

Phaserunner, CA, pas sensor and 2x 13s5p batteries in parallel. Frame is from an obscure chinese would-be-bullitt maker sold under various brands.
https://www.clamberbikes.com/Cargo-Bike-pl3386622.html
https://bbf.bike/cargo?catID=1213

 

[Jil]

Thanks !

 

[Jil]

I have discussed the possibility to install a motor on the front wheel of a long john with a bespoke frame manufacturer.
He has some doubts about the resistance of the fork/headset on the long term.
What are your thoughts ?

 

[john61ct]

By resistance, do you mean durability?

 

[Jil]

Yes. He fears that the motor could create constraints on the fork and the headset.

 

[amberwolf]

Yes. He fears that the motor could create constraints on the fork and the headset.

constraints?

 

[Jil]

Yes. He fears that the motor could create constraints on the fork and the headset.

constraints?

I mean mechanical strain on the fork and the headset.