Heavy cargo and steep hills: Will my plan result in injury and carnage?

arthurtuxedo

100 W
Joined
May 16, 2017
Messages
111
Location
San Francisco, CA
Max speed: 18 MPH
Range: 30 mi
Donor bike: Worksman Low-Gravity LGP
Rider weight: 150-250
Cargo weight: 200-300
Max grade: 20%+

I have started working for a company that hauls around small but heavy objects (6 objects weighing 35 lbs each, 8 or 9 of them would be ideal) to destinations all over the city, and I want to propose that we start using electric cargo bikes to do this. However, this is going to be a very specialized build given that our cargo will weigh around 200 lbs and we sometimes have no choice but to haul it up very steep hills. The only common motor that I can think of that can pull this off is the BBSHD, and I like the Worksman bikes because they are so heavily built and the LGP model has a steel box on the front that can fit our cargo and take a padlock for when we need to leave the bike for 5-15 minutes.

Worksman offers their bikes in either single-speed or 3-speed Sturmey Archer with either a 36 or 44 tooth front sprocket and 20t rear. According to Sheldon Brown, that gives 35-62 or 43-76 gear inches and a top speed of either 18.5 or 22.6 MPH @ 100 RPM. The low top speed is good because I am not confident in the ability of a Sturmey-Archer coaster brake and the Worksman front drum brake to stop ~500 lbs of gross weight at speeds higher than that. In fact, on a descent I'm not confident that they can stop the bike at all, which is one of my concerns and a reason that I am posting. The drum brake is listed as C6LG, and a Google search doesn't reveal anything about what kind of stopping power it has. I would just throw on a front hydraulic disc but I don't know whether the fork can accept one or not, or whether it has clearance for rim brakes either.

My other concern is the amount of torque that would be applied to the drive system carrying a lot of weight up a steep hill. It seems like a BBSHD could glide right up at only 35 inches of gearing, but I wouldn't want to order everything and find that the motor is burning itself up in the attempt or the chain snaps in two or the torque grenades the gear hub.

I also looked at the eRad 1000w Yuba Mundo, which has a lot more gear range and the huge advantage of being a turn-key solution that I wouldn't have to wrench together, but accessing the cargo from panniers or Wald baskets would be less convenient than a front box and I can't think of any way for us to leave the bike while we go around the corner and not have our gear get stolen.

Please let me know if the Worksman LGP + BBSHD is a good idea or would require a lot of additional work to be made viable!
 
Well, the first thing I see is the box position. Unless you have arms like "popeye the sailor man" controlling that much weight on the bars is not really feasible. You would probably have to do heavy modification to the bars, forks, and axle to reliably carry that much weight. Over time, that bike or any other stock bike will ware heavily to the point of breaking. Unless you crashed first..... :oops:

A better idea for that much weight is a two wheeled trailer. Or maybe a trike. Besides taking the weight off the bike for safety, a trailer could handle a larger battery for longer delivery times or repeat runs. People like BOBGear trailers because they are connected to the rear axle so they are stable going down hills. They may not be rated for your weight though.

BB motors are fine if they fit or you can make them fit. Rear DD motors are fine as well. For something like you want I would go with a 48v rear DD motor and at least 60v battery and controller that can handle the amperage.

Since you want to move the weight of two men, something like a converted bicycle taxi might be a better idea if the motor is in the back because front drive motors can slip going up hills. The BB motor is only as strong as your chain.

:D
 
I think you could make that LGP technically functional, if you throw enough time and money at it. I don't think it's worth your effort. the high center of gravity over the front wheel, massive weight, and trying to drive off the back wheel would be a handling nightmare. the IGH wouldn't hold up, so you would need to stretch and weld on the frame to fit a normal style derailleur and gears in the rear, and the massive battery would be hard to fit to such a small frame. Overall, it's just not a good bike for what you said you want to do.

A bike like that was designed to hold 10lbs of Pizza, not 200lbs of dead weight. It isn't going to be stable with that kind of weight.


The Mundo looks like a good bike. Lots of people use them for hauling everything imaginable. the weight low on the sides over the rear wheel makes them far more stable.
Your motor choice is fine. the BBSHD should work. use a quality chain, and make sure you have gearing low enough for the hills. If you find it isn't enough power, you could always add a 500w front geared hub motor later, to assist on the hills.

If you need a big box for some deliveries, then get a trailer. One that holds 600lbs and can take the abuse of being used for commercial purposes is easy to get relatively cheap. Try a lawn tractor cargo trailer.

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You can carry a broken Yuba home on another Yuba, so there's that..... plus carry other stuff :D

yubayuba.jpgpassenger.jpg

But locking it all up is a challenge no matter what format you pick.
 
Thanks for the feedback! Is there a trailer that can carry ~300 lbs and features a locking box or an aftermarket one that can be installed without a lot of custom modifications? The Bikes at Work 32" looks like it would fit the bill, but I don't know about the box part.
 
Brainstorming, imagining hauling 8 25lb boxes of clay up and down hills in SF.

Surly Ted Trailer behind a Yuba Mundo with a BBSHD, huge gears in the back and a front hubmotor for extra power on hills? You could just use one motor or the other on flat ground, also run both quad piston disk brakes and rim brakes with dual levers. For security get a couple motion sensor alarms that really scream, if a thief set both off at the same time it would be hard to disable both, the one I've got can be hidden under the bottom bracket or under the racks. A couple of nice batteries of course, a couple 20+ah ones would be good.

I can't imagine going down wicked steep hills with 200 lbs of cargo would be real safe without a bike with a fairly long wheelbase and really killer brakes.
 
Why do you need a longtail if you're carrying the cargo on the trailer? Is it that a standard wheelbase bike would be more likely to tip instead of turning the trailer?

Are there any lockboxes / utility boxes that are a natural fit for a Surly Ted or a Bikes at Work 32" and only require some basic drilling to attach? I'm looking for a solution as close to off-the-shelf as possible. Money is a medium-sized object. It's not my money, but the more cost effective it is, the more likely my manager is to give it a shot.
 
arthurtuxedo said:
Why do you need a longtail if you're carrying the cargo on the trailer? Is it that a standard wheelbase bike would be more likely to tip instead of turning the trailer?

Are there any lockboxes / utility boxes that are a natural fit for a Surly Ted or a Bikes at Work 32" and only require some basic drilling to attach? I'm looking for a solution as close to off-the-shelf as possible. Money is a medium-sized object. It's not my money, but the more cost effective it is, the more likely my manager is to give it a shot.

Yeah I'm curious how a bike with a average wheelbase would do hauling a heavy trailer down hills as far as stopping, I just think of a lot of weight wanting to push you over the bars when braking hard. The Surly trailers sure look nice, I've thought about buying a Bill model just to cut out a few more car trips, could probably haul a bit of dimensional lumber and building supplies on one but I worry about me turning into a junk man riding around collecting free box stuff constantly since I always see so much good stuff on the curb.
 
arthurtuxedo said:
Max speed: 18 MPH
Range: 30 mi
Donor bike: Worksman Low-Gravity LGP
Rider weight: 150-250
Cargo weight: 200-300
Max grade: 20%+
[...]
Please let me know if the Worksman LGP + BBSHD is a good idea or would require a lot of additional work to be made viable!

That's a useful bike, but not for your application. It's a pizza bike, meaning the box already takes up most of its useful payload capacity before you put anything in it. It's optimized for very short delivery runs in a very flat city. (Those bikes are still handmade in Manhattan, for Manhattan conditions.)

Note also that Worksman bikes and trikes use American/one-piece crank bottom bracket shells, and it's not straightforward to mount a mid drive on one of those. It can be done, but it's a little bit hokey compared to using a frame with a threaded shell.

I have a front loader that I built, and it's bigger and badder than the Worksman (with a smaller box), but it starts to get shaky and unpleasant once I load 100 pounds into the box. For perspective, I'm 6'8" and close to 350 pounds. I don't think a 2-300 pound front load would scale well to a normal sized person.

rps20180301_005946.jpg

I think the Yuba would work fine if your small-but-heavy items are small enough to put two or three along each side and another two or three on the rack top. It's way more competent to carry the weight without drama, and it has the added benefit of a particularly nice ride quality because of the mid-wheelbase seating. It will go faster and farther on the same amount of battery power compared to the Worksman bike.

A bakfiets like the Cetma Cargo or Human Powered Machines Long Haul would do your job nicely, with easy supervision of the cargo, but at a higher price than the other options that have been brought up. (Except for the super heavy and super expensive pedicab trikes that speedmd suggested.)

Another option is a heavy duty trailer like the Surly Ted or a Bikes At Work trailer that would allow you to do the job with a relatively normal bike that could serve as a commuter when not hauling big loads. This option becomes scary on steep hills when the trailer weight exceeds the bike's gross weight.

Once you stipulate 20% grades with a heavy load, the BBSHD looks like one of the few good options you have. That's a harsh thing to do to your drive components, so my advice is to use 7- or 8-speed shifting so it's affordable to replace chains and cassettes as often as you need to. Get a chain checker and use it often.
 
I think a trailer with a "regular" ebike (middrive) is probably your best bet, but if you want the cargo on the actual bike:

If you don't mind trikes, and you're willing to build your own, you can copy the SB Cruiser's basic design. There's a number of tradeoffs in it due to parts I had to use that I already had, that could be improved if designing from scratch with whatever was needed (rather than whatever you had to work with).

But even as it is, it'll haul the cargo, and you can easily make the whole back end a lockable box design instead of an open one. If you have tall cargo, leave the rack off. If you don't have a lot of sun or rain, leave the canopy off for better aerodynamics (and better range for the same battery).

If you have cargo bigger than the bed will take, hook a trailer to it (as-is, it's hauled almost 600lbs of dog food at once, most in a trailer, some in the bed, albeit on the flats).

You'd probably want a middrive thru a transaxle (maybe a peerless diff) rather than the DD hubs I've got (because of your hills).

If you built them out of good cromoly instead of the mild-steel junk I built it from, they'd probably be notably lighter than mine.

https://endless-sphere.com/forums/viewtopic.php?f=2&t=67833
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Some thing like AW's trike, or a big two wheel trailer towed. its way too much weight for the food delivery bike design. Ever carried 300 pounds in a wheelbarrow? imagine it starts to tip, but its 2 feet higher in the air. Yee hah! Even popeye could not keep it from dumping.

Cargo bike to carry the battery would be nice, as well as better on the wheels and your ass. (because it teeter totters, instead of just pounding that back wheel) but in fact, the battery could go on the trailer.

20" wheel, even with the mid drive is definitely what you need.
 
I'm liking the trike idea, if a person could afford to have a custom frame built with a long wheelbase and 200mm double or triple crown forks extending out in front like the one pictured above, a nice locking cargo box built on the back, motor (motors?) with enough power to enable you to pedal it up most any hill, killer brake system (motorcycle quality dual disk?) it could be an incredible delivery vehicle and quite safe if overbuilt.
 
Trikes are awesome for carrying big loads. Cargo trikes are not awesome for going 18mph, and they're awesomely terrible on steep hills. They will fight you for the right to go straight down whatever hill you're trying to go up or across. I own a couple of trikes and I build a lot of trikes, but for the kind of hills the OP specifies, I'd use a two wheeler.
 
Would think a Big advantage of a trike is that it does not need to be kept from crashing to the ground when it has a 300 pound load. Don't have a clue what you would do with such a load when coming to park on uneven ground and not having a well thought out stand setup on a bike. Trailer would solve much of those issues. None of these scenarios sound very appealing on steep stuff.
 
speedmd said:
Don't have a clue what you would do with such a load when coming to park on uneven ground and not having a well thought out stand setup on a bike.

Locking brake levers make all the difference for my cargo bike. Yes, I need something to prop the bike against, but that's really all I need to park it securely. Many of the pedicab trikes in the fleet I work with have a locking front lever too, to keep the trike from pointing downhill and taking off on its own.
 
Chalo said:
speedmd said:
Don't have a clue what you would do with such a load when coming to park on uneven ground and not having a well thought out stand setup on a bike.

Locking brake levers make all the difference for my cargo bike. Yes, I need something to prop the bike against, but that's really all I need to park it securely. Many of the pedicab trikes in the fleet I work with have a locking front lever too, to keep the trike from pointing downhill and taking off on its own.

Curious how steep of a slope can you safely take your Pedicabs up?
 
Chalo said:
Cargo trikes are not awesome for going 18mph,
SB Cruiser is. Whatever is different about it's geometry and weight distribution, it isn't tippy and it makes turns at speed fine, even as high up as the seating position is. It'd be even better if I lowered the seatbox top to lower the CoG with me on it.

and they're awesomely terrible on steep hills. They will fight you for the right to go straight down whatever hill you're trying to go up or across.
Can't say much about how SBC would do on long steep hills, but it works on the down and up ramps on the canal path underpasses (that go under the major roads so you never have to cross any roads for miles, staying just on the path). They're pretty steep, but I don't know what angle, and they're not very long, maybe a few dozen feet from top to bottom, then again back up to the top, at a guess.

Maxed out on the almost-4kw power going up, though, even if I conserve momentum by not slowing on the descent. ;)


As long as the road is not crowned steeply, I can let the bars go and it'll track relatively straight at speed, though since until today it was throttle only (I can't pedal enough to go more than a few MPH), I dont' know how long it will track.



FWIW, one thing about a trike is you can go up the hill as slow as you need to, assuming you have the gearing to do that and not burn out the motor (or pedaller), since there's no worry about balancing (a problem with at least some, maybe most, 2-wheelers at very low speeds, and worse with a heavy load).
 
Raisedeyebrows said:
Curious how steep of a slope can you safely take your Pedicabs up?

That's a good question. They're long, with really good brakes and deep reduction gears and fat 29" tires. I imagine it's all a matter of how low the gearing and how much pedal or e-bike motor power is available. Traction, braking, and weight distribution are all covered.

I once built a parade trike with 11" low gearing and used it to drag 3200 pounds gross up a significant hill (~5%), pedal power only. So where there's a will, there's a way.
 
About the heaviest load I've carried up hills on the Yuba Mundo is a couple boxes of clay and a couple gallon buckets of glaze, like that it definitely is a lot easier to handle than a fully loaded touring bike with weight hanging off the rear rack. I think the guys I've read about who were doing the cargo bike music collective were hauling a couple full sized PA Mains on the Yuba side racks, My old PA Mains were about 105 lbs each and I do not think I could have handled the bike with those on it (I'm a flyweight, Chalo probably could have no problem at his size) I replaced them with lighter ones because I couldn't move them up the stairs without assistance. Theirs might have been a bit lighter and I don't know if they climbed any hills although since they were in the Bay Area I suspect they did, if they climbed any just pedaling without the assistance of a motor I've gotta give them props, with just my 60 lb daughter on the back of mine I'm dead in the water as soon as I hit any hills without the motor.

I think the Yuba has a claimed max weight rating of 400 lbs and probably anything approaching that is putting the rear wheel to the test although they are a decently strong 48 hole wheel with 14mm axels. Swapping wheels to a 20" would get weight down lower like someone commented above.

Teklektik's Yuba Mundo build really impressed my since I first saw it, he had a great idea with the two motors, what a beautiful and practical bicycle!
 
Thanks for all the great feedback! I don't think there's another place to come for advice on such a niche application. I'm currently thinking that the best bet might be a 32A Bikes at Work trailer with a utility box screwed onto it. There seem to be a variety of such boxes made for pickup trucks that have similar dimensions to the trailer and can take a padlock. For the bike I'm leaning towards the Roam Fusion from Lunacycle since it comes with the BBSHD already setup, has a warranty, and has enough range to last for an 8-hour shift with its 34 Ah monstrosity. Other than attaching a utility box, which our mechanics should be able to manage easily, it's a completely off-the-shelf solution and a relative bargain.
 
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