Thoughts on cargo bikes

I am thinking about building or buying a bike that can carry large loads including a large battery or a second adult human. This bike would effectively be a car replacement for me. I would like the ability for long distance travel, say ~70mi or so.

I was looking at the juiced bikes odk-u500. What has me concerned is the small geared motor, a 500W BAFANG BPM, on a heavy bike ~70lbs + ~400lbs of human. A weak motor plus a 20" wheel may have this bike going pretty slow. I wouldn't mind being able to hit ~25mph once in a while. I am worried that there may also be the risk of the motor overheating with so much extra weight on it.

https://www.juicedbikes.com/products/odk-u350?variant=28381726226

I was also looking at a Kona Ute. I would convert this myself with a 26" 1000W rear hub motor I have. Hopefully, with a big enough tire, the switch from 700c to 26" on the back wheel will work.

https://2017.konaworld.com/ute.cfm

Any thoughts on which would be the better choice?

What's the terrain?

The Yuba's are pretty popular in my area. If you have hills, maybe the Spicy Curry?

https://yubabikes.com/cargobikestore/spicy-curry-bosch
https://www.youtube.com/watch?v=44QeMdPNQh8

Wish they'd make an open (non-Bosch) version.

Big hills + heavy loads need lots more oomph

A really capable car replacement is going to need a direct drive motor or something else that's simple and durable. It also needs enough power; more than what is available in the white market

So you're going to need to build your own.

john61ct said:

Wish they'd make an open (non-Bosch) version.

Big hills + heavy loads need lots more oomph

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The Sweet Curry makes for a great conversion. Lot's of room for battery. I can cruise at 22-25 mph with 450W, but less when fully loaded up. A bigger mid-drive should do it. The small rear wheel leads me to use a 50T chainring, which reduces chain force for a given crank torque, so you can put a lot of power through the bike chain!

neptronix said:

A really capable car replacement is going to need a direct drive motor or something else that's simple and durable. It also needs enough power; more than what is available in the white market

So you're going to need to build your own.

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I agree on the reliability of a DD. I want something I know will just work, especially if I plan on long trips. I was considering buying the juiced cargo bike and swapping in a more powerful motor. Hopefully I can find something in the 1000W-1500W level in a 20" wheel. Of course I may need to bump up the voltage to get any kind of decent speed with it.

E-HP said:

What's the terrain?

The Yuba's are pretty popular in my area. If you have hills, maybe the Spicy Curry?

https://yubabikes.com/cargobikestore/spicy-curry-bosch
https://www.youtube.com/watch?v=44QeMdPNQh8

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Terrain will be mostly road use. Mostly city, so some hills and stop and go. I'd like to make a long trip, 60-70mi a couple of times a year.

transposon said:

I agree on the reliability of a DD. I want something I know will just work, especially if I plan on long trips. I was considering buying the juiced cargo bike and swapping in a more powerful motor. Hopefully I can find something in the 1000W-1500W level in a 20" wheel. Of course I may need to bump up the voltage to get any kind of decent speed with it.

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Yeah, the sad thing is that you'd be buying this bike and ripping out every electric part :/
The xtracycle edgerunner is kinda cool because it can handle a 20" rear wheel. Then you can pop a motorcycle/scooter tire on the back and stop worrying about rear flats so much.

If you are 400lbs then you'll want to be very picky about the weight rating of regular bike frames.

I'm not 400lbs yet! Although pizza is delicious. 400lbs would be for two people.

I'll check out that bike. edit - wow, those are expensive!!. Way out of my budget unless I can find them used.

neptronix said:

A really capable car replacement is going to need a direct drive motor or something else that's simple and durable. It also needs enough power; more than what is available in the white market

So you're going to need to build your own.

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That's how I ended up with first the CrazyBike2, and now the SB Cruiser.

@transposon:
At the weight you're looking at, and speed and distance you want to go, I think you should just build your frame from scratch, and I would recommend a motorcycle rear wheel if you're going to use a single 20" rear wheel (like the bikes you're talking about converting, and my CrazyBike2). It'd be a 16" MC wheel, for the equivalent, and it'll come out more like 22" outside diameter.

Otherwise there is just so much load on that wheel that if you don't have suspension, you're likley to damage a bicycle rear wheel (I've done in quite a few on that bike, and on SB Cruiser, before going up to something halfway between MC and BC, but even with those, the rims get damaged by potholes with all that weight). Even *with* suspension you may break the bicycle wheels on bad roads, if it's not designed to give you the travel/etc you need for the load you have on it at the time and the road conditions.

If you go with a delta trike (like my SB Cruiser), it spreads the load between the two rear wheels, so in my case I've had far less problems with the hybrid wheels (bicycle spokes, small MC/moped rims, big DD hubmotors) than CrazyBike2, and even bicycle wheels survived longer on it.

But if you can go with larger wheel diameters, 26" or 29", bicycle wheels would work better, for ride quality, with no or not much suspension.


As for motors, controllers, and batteries...what kind of acceleration are you looking for, under max load?

I recommend you go to http://ebikes.ca/simulator , read the entire page so you know what things are and how they work, and then play with various systems both single and dual motor, to see which will do what you want.

With 500lbs+ of mass on SB Cruiser, using only one of the two rear MXUS 3K hubmotors in the 20" (22") wheels, at between 1500-2000w (14s pack, 35A max Grinfineon controllers x2 ATM), it can take 10-15 seconds to reach 20MPH from a stop, depending on conditions. With both motors, it's more like 5-6 seconds.

Similarly, the 1/5th lighter CrazyBike2 when I had the same pack type/etc but 2x 40A controllers and an HSR3548 in a 20" rear and 9C 2810 (I think) in the front 26", would be 4 seconds to 20MPH with both motors, but again, much slower acceleration with just one or the other (the smaller rear wheel accelerated better than the front larger one).

Hi

I don't know how serious you are about using it as a car replacement, but if it is so, I would recommend that you get a bike with a bed for your stuff. I'm from DK where this style is all we use, so I might be a little biased, but IMO this is by far the greatest kind of cargo bike because it is so flexible.

Something like the harry vs larry bulitt



Or the triobike cargo



Or even the triobike cargo big



With these sort of bikes, you can not only move yourself but also a little bit of stuff, which I find a big advantage over the other suggestions here.


As far as drivetrain, I disagree with the others that recommend DD hubs, as I honestly think they're the dinosaurs of ebiking. I think a geared hubmotor with a torque sensing BB is the way to go, because you are building a bike and not a scooter

Edit:

Just browsed through what might be locally available to you and found this riese and muller bike with a bosch motor. It is ridiculously expensive, but ticks all the right boxes IMO.

https://www.r-m.de/en-us/models/load-60/

transposon said:

I'll check out that bike. edit - wow, those are expensive!!. Way out of my budget unless I can find them used.

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What's your budget, then? 70 miles worth of battery isn't cheap on its own. Neither is a bike that can carry a passenger.

My budget would ideally be ~$1000 not including the battery. I built a ~1.2KWH 52V pack already. I also have some lipo as a backup.

transposon said:

My budget would ideally be ~$1000 not including the battery. I built a ~1.2KWH 52V pack already. I also have some lipo as a backup.

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Well, that eliminates a few options. If I were trying to do what you're describing, I would get a good sturdy used MTB from the '80s or '90s (rigid fork, straight tubing) and try to find a secondhand Xtracycle Free Radical. That would leave enough room in the budget for a BBS02, and maybe even an upgraded rear wheel.

transposon said:

My budget would ideally be ~$1000 not including the battery. I built a ~1.2KWH 52V pack already. I also have some lipo as a backup.

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Probably should have started out with that.

Hopefully your Craigslist skills are up to the task.

Here my two cents:
- long johns are less versatile than long tails, and usually quite a bit heavier and super expensive (Bullitt 1600€ for just a framekit - really!?!)
- With a long john, you basically always carry the extra weight, even if empty, while with a long tail, extra weight is minimal.
- Packing is easier on a long john though, as is carrying kids (you always see them) but not adults.
- Long johns are also not built for higher speeds,as the front wheels tends to flatter. Putting the motor front seems to help though.
- Long tails with steel frames provide some sort of suspension.
- hub motors are great for cargo (regen = 3rd brake), but work MUCH better on small wheels (like 20")
- small wheels have limited carrying capacity and make for a harsh ride if unsuspended
- rear suspension seriously limits the bikes stability when heavily loaded and limits trailer options
> solution is either a 20" front motor in a suspended fork, or a a 20" rear wheel with large tires. First one you can do on any long john, second one is trickier. I find 20x3 a good compromise, like this bike:


I didn't try it though. One bike I have here is this one:

Very comfy; perhaps I'll post the build thread.

I hope this helps.

The juiced bike has a good idea for the frame. I copied it for the best e bike I ever built. But yes, the 350w motor will be inadequate for climbing big hills with a double load.

dogman dan said:

The juiced bike has a good idea for the frame. I copied it for the best e bike I ever built. But yes, the 350w motor will be inadequate for climbing big hills with a double load.

Finished cargo mixte..jpg

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I believe this is the version with the 500W geared hub motor. Would this be adequate for heavy loads at 20mph?

transposon said:

dogman dan said:

The juiced bike has a good idea for the frame. I copied it for the best e bike I ever built. But yes, the 350w motor will be inadequate for climbing big hills with a double load.

Finished cargo mixte..jpg

Click to expand...

I believe this is the version with the 500W geared hub motor. Would this be adequate for heavy loads at 20mph?

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Based on the specs for the 500W version of the bike, assuming the largest battery capacity. Used an 18A controller based on the peak spec, and twice that for the phase limit, assuming no pedaling:

https://www.ebikes.ca/tools/simulator.html?motor=MBPM&batt=cust_48_0.2_32&mass=213&axis=mph&wheel=20i&hp=0&cont=cust_18_36_0.03_V



You can play with the assumptions and put in a grade if you have hills.

What's missing is the temperature data, so you can't tell whether it will over heat. I noticed reducing the weight down to 220 only increased the speed by 0.5 mph and dropping 50 watts, so I assume it wouldn't be an issue on flat or small grades.

You won't hit 70 miles unless you pedal, or if you can drop your total weight down to 145 lbs. Also looks like anything over a 3% grade will kill the motor.

EDIT: Looks like if you slow it down to 17 mph, you can get the 70 range, no pedaling.

transposon said:

I believe this is the version with the 500W geared hub motor. Would this be adequate for heavy loads at 20mph?

Click to expand...

The problem with a hub motor for a heavy cargo bike is that it will only behave optimally within a narrow range of speed. Driving the crank is a much better technical solution, because you can use the bike's gears to match load, speed, and available power in changing conditions.

With a hub motor, you either have to have an abundant surplus of power to make it all work, or you have to match the RPM of a low powered motor to the highest load it will encounter (and accepting the low cruise speed that imposes).

If you know what hub motor you are considering, and how much weight and slope you have to deal with, you can use the Grin motor simulator to figure out the speed your motor can go at its peak output, with that much weight, up that steep a slope. BLDC motors generate their maximum power at half of their free speed, so you can figure out what maximum RPM you're looking for. My guess is you'll need a fairly slow winding, or else a high powered motor, battery, and controller.

I think you may want to take a look at this build.

https://endless-sphere.com/forums/viewtopic.php?t=78828

wturber said:

I think you may want to take a look at this build.

https://endless-sphere.com/forums/viewtopic.php?t=78828

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Recumbent layout seems like a great way to make an extra-long and ungainly cargo bike that carries a small fraction of the usual amount of cargo. Doing less with more, the recumbent way!

Edit, i confused this thread with another I think, one that included some large hills. I'll leave the text anyway, for those that do have hills. The thing to do to go 70 miles, regardless of the weight, is slow down. ride 15 mph tops, and your battery will last. Assuming your second person will not pedal, you need a lot of battery. It will take 500w continuous to go 15 mph if you weigh 500 pounds or more. so 15 mph, into 70 miles. About 7 hours of ride time. 500 watt hours per hour, so you would need about 3000 to 3500 wh of battery. looking at about 50 pounds of battery.

To carry that second person and go 70 miles,, you really need to build an electric tandem. double the amount of pedaling, and your can pedal up a lot more of those watt hours it will take.

A 500w rated geared motor will have about a 300 pound total load limit when climbing long, steep, above 5%, hills. That is in 26" wheel though. I never tested to melt down a motor of that class in 20" wheel. It ( 20" hub motor) should be able to do closer to 400 pounds up 5%. ( in the 26" wheel test, 5% melted the motor with 400 pounds, but 300 pounds worked ok to 7 or even 8%)

My advice is to evaluate your load. If its 400 pounds or above, meaning everything, you, bike, battery, motor, cargo, then you should be looking at a DD motor at least, and ideally one with a lot of copper wire and magnet. In other words, shop in the category of motors that weigh 25 pounds or so without spokes or rim.

Or, go with a mid drive. Mid drive can gear down, and then run up the mountain very slow without getting the motor rpm into the making more heat than motion rpm. 1000w ( on a 500w class motor) can get you up a mountain with lots of load, but much slower of course.

Any hub motor, needs to climb a mountain at 15 mph at least in 26" wheel, or 12 mph in 20" wheel to stay cool. No matter what type. As the load increases, you simply need more power. So a big DD that can pull 2000w continuously, even for an hour or two to climb a mountain, is best for a very heavy cargo bike. And again 20" rear drive wheel if possible.

That bent build is very cool. Looks like a 500w geared motor to me on it. But what I don't see, is the 100 to 150 pounds of cargo, or any talk about it climbs the rocky mountains.

There is a similar trend though, the best cargo bikes do tend to employ some frame modifications, to carry the battery. On my custom frame the 20" wheel was a definite part of the design, but the bike was really built simply to carry batteries. Two in the frame, for 2000 wh, plus the possibility of two more in the panniers. The cargo was to be essentially, 60-80 pounds of batteries. I did some nice long rides on that thing, before the garage fire took it.

Balmorhea said:

wturber said:

I think you may want to take a look at this build.

https://endless-sphere.com/forums/viewtopic.php?t=78828

Click to expand...

Recumbent layout seems like a great way to make an extra-long and ungainly cargo bike that carries a small fraction of the usual amount of cargo. Doing less with more, the recumbent way!

Click to expand...

Recumbents or semi-recumbents are worth considering since the OP specified long distances of around 70 miles. The recumbent provides lower wind resistance and for many people greater comfort. This particular recumbent covers 100 miles in a day with ease. It goes well over 30 mph, and with a 22 mph average on a long trip consumed 17.4 wh/mi. These are desirable attributes. And if cargo carrying was more of a priority, it would be easy to add a rear rack for additional capacity.
But yes, there are always trade-offs.

dogman dan said:

That bent build is very cool. Looks like a 500w geared motor to me on it. But what I don't see, is the 100 to 150 pounds of cargo, or any talk about it climbs the rocky mountains.

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It is a Crown 4080 and he sends it over 2500 watts at times. I'm betting it handles hill fairly well. Though I'm not sure with 400 lbs of human beans onboard.

I agree that this particular bike is not optimized for the 100-150 lbs of cargo - though he does haul his recycling stuff on it. But it would be easy to add a rear rack/platform where you could also attach a seat.



Anyway, I'm not saying this is what the OP should do. But it does cover some of his criteria and provides some food for thought.