Fast Electric Cargo Bike for my Bay Area Commute

I posted a few weeks ago asking some initial questions about building an ebike for my commute. I've updated my expectations and thought I'd make a new post with more information.

I'd like to build a fast ebike for my commute.

My Commute:
https://www.strava.com/activities/2740310450
I can charge batteries at home and at work.

The bike I'm considering:
https://sfbay.craigslist.org/sfc/bik/d/san-francisco-surly-big-dummy-long-tail/6995711420.html

My performance hopes:
30 miles distance, 30-35mph on flat areas
Slower on hills
I'm a strong cyclist and would likely assist 200+ watts for the entire commute

I'd like the conversion to be as simple and reliable as possible.

Questions:
1) I see a lot of mid-drive setups (Bosch?) - is this better than a hub motor for my purposes?
2) I'd like a simple charging solution with "built in" BMS. These used to be called A123 Batteries, I believe. Are those still around? I previously used LiPo batteries which I'd like to avoid this time because I don't want to worry about exploding batteries and balancing correctly.
3) Are there downsides to using this specific bike that I'm considering?

Any suggestions/advice welcome!

Mid drives would suit your needs quite well.
I highly doubt you'd be able to install a Bosch motor on your Surly, as those motors are for manufacturers. Companies like Specialized, for example would use their proprietary blend of parts - not good if something were to break a$ then you are a b!t(h to the man who bring$ $and and gla$$ for the bending over ceremony.

Grintech makes a neat mid drive system called Stokemonkey.
https://www.ebikes.ca/shop/electric-bicycle-kits/middrive.html

However even a regular style mid drive system would work, like the BBSHD and the CycloneTW.
https://em3ev.com/shop/?prod_cat_=middle-motor-kit
https://cyclonetw.com

Be wise to buy everything from one place, motor + controller + battery.




How will your bicycle be secured?

The Yuba Mundo Lux would be a better bike for about the same price because ... it is New and I think has a better aft end design on the frame .
https://yubabikes.com/cargobikestore/mundo-lux
I personally would buy a Yuba over a Big Dummy , look at the rear of both bikes .

You want to go that fast and want to do it on only 200 watts ?, on a upright and heavy cargo bike ?
No way Jose .

The people who have allot of experience in cargo bikes, commuting on a e-bike, and electronics is ... Grin Technologies
I will let them tell you all you need to know, just e-mail them they have have done what you want to do for many years now. It would be good to buy from them as well since it is best to support those who constantly make improvements in the E-Bike World .

markz said:

Mid drives would suit your needs quite well.
I highly doubt you'd be able to install a Bosch motor on your Surly, as those motors are for manufacturers. Companies like Specialized, for example would use their proprietary blend of parts - not good if something were to break a$ then you are a b!t(h to the man who bring$ $and and gla$$ for the bending over ceremony.

Grintech makes a neat mid drive system called Stokemonkey.
https://www.ebikes.ca/shop/electric-bicycle-kits/middrive.html

However even a regular style mid drive system would work, like the BBSHD and the CycloneTW.
https://em3ev.com/shop/?prod_cat_=middle-motor-kit
https://cyclonetw.com

Be wise to buy everything from one place, motor + controller + battery.




How will your bicycle be secured?

Click to expand...

Thanks for the response. When you say "Secured" are you asking where I'll lock it up?
My workplace allows me to bring my bike indoors to a secure bike rack. Someone would have to walk past our security team with my bike to steal it.
At home I have a safe garage.

ScooterMan101 said:

The Yuba Mundo Lux would be a better bike for about the same price because ... it is New and I think has a better aft end design on the frame .
https://yubabikes.com/cargobikestore/mundo-lux
I personally would buy a Yuba over a Big Dummy , look at the rear of both bikes .

You want to go that fast and want to do it on only 200 watts ?, on a upright and heavy cargo bike ?
No way Jose .

The people who have allot of experience in cargo bikes, commuting on a e-bike, and electronics is ... Grin Technologies
I will let them tell you all you need to know, just e-mail them they have have done what you want to do for many years now. It would be good to buy from them as well since it is best to support those who constantly make improvements in the E-Bike World .

Click to expand...

Are you saying that 30-35mph on flats isn't doable on a cargo ebike? 200watts is what I would be putting out in addition to what the ebike does. I've ridden around on some cargo ebikes at work that are capable of 25mph (no pedaling) off of a battery that looks like a waterbottle. I'm surprised to hear an extra 5-10mph isn't doable with a beefier motor/battery.

A few issues here.

First you are in luck faster speeds are somewhat better with a long wheelbase bike like the Yuba.

The hard part is you want to go both fast and far. this does not work on e-vehicles unless they are aero and have very large battery packs.

For faster speeds on up right bikes you will need over 1k watts , even often over 1.2k and that is on flat ground with no wind .
The faster you go the more watt hours or some people use amp hours you will use .

So to do what you want to do, you will need ...
Powerful Motor over 1k watt constant
20-30 amp hour battery pack , at least a 14s/52 volt pack
and to get aero a dropper post for when you are going down hill to reduce drag
& aero bars up front if you are used to riding road bikes to get better a aero position .

Everything you want to do is possible as long as you count on using over 20 amps of battery usage per trip ( one way )
so a 25-30 amp pack will be better with a charger for work as well.

Do you expect to be able to do both forwards and backwards on 1 charge or are you alright with charging halfway?

Either way, I suggest you get the TSDZ2 motor because it has a torque sensing feature. It will make for a much more natural feel than throttle operated ones IMO.
If you are interested in nerding out, there is custom firmware avalable for this motor, which makes it even more awesome. If you don't feel like that, then don't bother.
I disagree with the power figures, the others are putting out. If you lean a bit forward and assist yourself, you will easily hit 20 mph with a 500w motor, but 25 might be stretching it a bit.

If you don't want to charge, you need a really big battery. I think that would have to be made to custom order somewhere, either in China or locally. This will also make the bike rather heavy. If I were you, I would look into long john style cargo bikes like the Harry vs Larry Bullitt, which is much more suitable to run a very heavy battery pack, as you can put it on the bed.

Edit:

Just read through your post again.

Honsetly, I think you should just get a geared hub motor. They are cheap and powerful and reliable. The feel is a lot crappier than a mid drive and the bike will feel more like a scooter, but it will be simle, powerful and reliable.
I also noticed that you can charge at work. That means you need a smaller battery pack than I thought, but it will still need to be pretty big.

I have pretty much built that bike (after many trials-and-error) and can share my experience.

Motor: Mid-drives are generally better for hills if you don't have much power. I find them not very reliable for commuting at the speed you are looking at. Hub-motors are much more reliable and cheaper. If you can take it easy on long hills you'll probably be ok just use a temp sensor and monitor temp. I'd recommend a 1500W 35H (35mm wide motor) often known as Leaf motor:
https://www.aliexpress.com/item/32684201103.html?spm=2114.12010612.8148356.3.5ae9c409tj8c5z

Battery: 52V min - but recommend 72V if you want to comfortably go 35 mph. 30 miles would require about 1.5 kWh, but I'd go a bit bigger if you can fit/afford it. I build my own know, but I hear emv3 is good.
Controller - assuming you are going hub, you'd want at least 40A @ 72V and make sure to get a sinewave controller.
https://www.aliexpress.com/item/32794585678.html?spm=2114.12010612.8148356.1.e749f9d1xKZDUt

Here's my heavily modded Radwagon (I got it used and was already quite modified, but the frame is a great platform:
I built a two separate triangle battery housed in polycarbonate cover (one is 52V 30Ah the other is 72V 21Ah - both 140 18650cells) - bike has 30-50 mile range at decent/fun speeds (no speed limiter). The battery (BMS) has bluetooth capability and display to indicate battery temp, speed, remaining capacity and estimated range as well as individual cell voltage for diagnosis. Second, the 1500 W motor is laced to a rear moped rim and 3" moped tire which pretty much eliminates the risk of rear flats. Added steel fenders that clear the wider tires and four piston Magura MT5e hydraulic brakes.




As I said I've built mid-drive commuters (BBS02 and BBSHD), but sold them in favor of hub motors but YMMV.


If you like pedaling at +30mph (like I do) get a large chainring in front at least 56T, I have a 60T on my other fast ebike


Also, this Mongoose on Amazon might be a decent platform too:


https://www.amazon.com/Mongoose-8-Speeds-Drivetrain-Mechanical-Kickstand/dp/B07XHNSHTP

Note in regards to hub motors if using a geared rear hub motor then only a battery pack up to 52 volts.

If you want to use higher voltages , which is better for higher speeds then a Direct Drive rear hub motor only.

I am now running 14s ( 52volt ) for slower speeds and up hills , then 16s for more speed and 20s ( 72 volt ) for better speeds on my bikes now .

Some people buy from internet but it is much easier and better in the long run to buy all components from the same seller . If you can not call and e-mail a company then do not buy from them !
Make a test call before buying to make sure they speak English and will warranty or at least help with after sales of the Kit .

Only after you have converted a couple of bikes to electric should you buy different components from different places .

Battery packs should be bought from the leaders in battery pack making ... Grin Technologies , eM3ev.com , Luna , California e-bikes ( which sells the eM3ev.com packs ) .

Seems like you’ll need a final setup with something close to a 52 tooth chainring to pedal 90 rpm at 33.3 mph. As you ride faster, it’s difficult to contribute the same power that you can at slower speeds. If you go mid drive, not sure what your max chainring size would be for off the shelf motors.

With the factory gearing, it looks like you’d need to pedal 125 rpm, so if you can do that for 30 miles, you’re good to go, since I recall that there are 42 tooth options for some factory mid drive kits.


Sent from my iPhone using Tapatalk

cbr shadow said:

I posted a few weeks ago asking some initial questions about building an ebike for my commute. I've updated my expectations and thought I'd make a new post with more information.

I'd like to build a fast ebike for my commute.

My Commute:
https://www.strava.com/activities/2740310450
I can charge batteries at home and at work.

The bike I'm considering:
https://sfbay.craigslist.org/sfc/bik/d/san-francisco-surly-big-dummy-long-tail/6995711420.html

My performance hopes:
30 miles distance, 30-35mph on flat areas
Slower on hills
I'm a strong cyclist and would likely assist 200+ watts for the entire commute

I'd like the conversion to be as simple and reliable as possible.

Questions:
1) I see a lot of mid-drive setups (Bosch?) - is this better than a hub motor for my purposes?
2) I'd like a simple charging solution with "built in" BMS. These used to be called A123 Batteries, I believe. Are those still around? I previously used LiPo batteries which I'd like to avoid this time because I don't want to worry about exploding batteries and balancing correctly.
3) Are there downsides to using this specific bike that I'm considering?

Any suggestions/advice welcome!

Click to expand...

That's quite a commute. 60 miles a day. 300 miles a week. 1200 miles a month. If you do the usual 5 day/week job. This would be in range for most commercial ebikes at 20 mph. At 30+ it needs a lot more of everything - energy, wear, motor heat, brakes, battery capacity. Your commute is about equal to my round trip commute in distance and climbing. On that I found that regular ebikes barely had the range and climbing capacity for the one way of my trip or half your trip. Eventually my commuting machine would do the whole round trip without charging and at your speed, so equivalent to your one way trip. You can read about that machine, the link is in my signature, the SuperCommuter. Not quite what you are contemplating, but this is a machine that will do what you are seeking to do, so this is what you need to compare to.

A few crumbs from the experience of building and commuting with a bunch of ebikes.

Mid drives put a lot of wear and tear on everything. Chain, cogs, brakes, tires, battery, motor. A lot of maintenance is involved with over 1,000 miles per month. Bosch is a closed system, they won't let it meet your requirements.

Flat tires are a problem. Changing tires on the way to work can be problematic if you are on a time schedule. I don't like to change tires on the road. So I went for tough tires. I found that the toughest bike tires were not that great. Moped tires however worked. They brought the flat rate down to once per year. And they are about half the cost of a good bike tire. But they are heavy and require moped rims.

Brakes wear fast on ebikes, especially those without regen used in hilly country. With good regen or elecric braking the brakes don't wear out.

Geared hubmotors also wear out clutches and gears when they are used a lot, and they don't let the heat out. They are very prone to failure if their limited power capacity is pushed.

Regular DD bike hubs are pretty good. In my case the gradients (to 15%) were too much and they were getting very hot. So I went to a larger DD hubmotor. QS motor type, 50mm wide magnets. Churns out a lot of torque and also very good at regen for electric braking.

This wide hubmotor did not leave room for many gears on my 135mm wide frame. A wider frame could solve this. In my case I used an ATS two speed crank with one chainring to a single speed freewheel, set up for about 12 and 25 mph, so I could pedal and help it at up to near full speed, or at slower climbing speeds. It worked out pretty well. If the motor was offline I could pedal it on the level in the low gear. I can kick in 600 watts for a short time when climbing, on the flats I can help if I reduce the throttle a bit, at full speed I'm pretty much spun out. I tended to treat it more like "wind sprints" so I got some nice exercise without sweating. Pedal hard for a short time during a startup or climb, then rest a few minutes. No shower needed.

Maintenance wise there was very little. Fix the occasional flat, replace the rear tire every 3000 miles or so, the front lasted 3x longer. The single speed freewheel needed replacement occasionally so I eventually just changed it with each rear tire replacement. With electric braking the friction brakes did not wear out. Chains and sprockets didn't wear out, eventually they would but not often.

The battery ended up 18S 32AH (75V charged). It happens to be lipo but could easily be 18650 with BMS since you are interested in that. It was enough for the round trip, though I generally charged it at what would be the halfway point for your commute. Depending on your hills and speed you might need a bit more capacity.

Dual 203mm hydraulic brakes did a good job in the front. In the rear there was no room for a disc so the electric braking was rigged to a linear magnetic sensor and switch in the rear brake lever. This operated the regen/electric braking in the controller which was very controllable and didn't heat up the front discs.

Best of luck on your challenging project.

Linear Magnetic Sensor ... What does that look like ? Where can one be bought ?

And the switch as well ?

Did you connect the linear magnetic sensor and/or switch to the brake wires of controller
or
To the 2 white wires / connectors on the controller that is often used for regen on infineon/lyen controllers ?

Did the linear Magnetic Sensor adjust the amount of regen ? and or dictate at what speed regen started ?

Alan B said:

In the rear there was no room for a disc so the electric braking was rigged to a linear magnetic sensor and switch in the rear brake lever. This operated the regen/electric braking in the controller which was very controllable and didn't heat up the front discs.

Best of luck on your challenging project.

Click to expand...

I want to pause for a moment and ask about your requirements.
The first thing is, why a cargo bike? I see the length of the commute and I understand the need for speed but I'm curious to what's getting hauled with you?

I wonder if maybe you're trying to get one bike to fit two tasks, your local grocery/stuff hauling, and your long commute.

I wanted to share my thoughts on the donor you've posted. I've got a big fat dummy and it rides great. Steel is real. Everyone suggesting mundos or rad wagons might be underestimating how much power you are going to be adding yourself. Getting a big heavy frame like a Mundo is going to make your life harder. The big dummy is going to feel so much better to ride and handle those speeds so much better.

Have you looked at the Big Easy? It's expensive, but it might be a good choice just due to your use case.

As someone mentioned, you're doing 500kms a *week*. Immediately I think that rules out the tsdz2, as with your use, you'll be doing maintenance on it multiple times a month. They are not the most reliable mechanically. The bbshd however is. The one thing I can't speak to is how a non torque sensing middrive feels when you're putting in 200 watts. I see this series of motor being put on mundos to be ridden by weaker riders at low speeds.

I almost wonder if it's worth you getting a custom titanium frame built to accommodate the 1000w bafang m620.

ScooterMan101 said:

Linear Magnetic Sensor ... What does that look like ? Where can one be bought ?

And the switch as well ?

Did you connect the linear magnetic sensor and/or switch to the brake wires of controller
or
To the 2 white wires / connectors on the controller that is often used for regen on infineon/lyen controllers ?

Did the linear Magnetic Sensor adjust the amount of regen ? and or dictate at what speed regen started ?

Alan B said:

In the rear there was no room for a disc so the electric braking was rigged to a linear magnetic sensor and switch in the rear brake lever. This operated the regen/electric braking in the controller which was very controllable and didn't heat up the front discs.

...

Click to expand...

Click to expand...

This is in my SuperCommuter thread with photos. The linear magnetic hall sensor looks like a small signal transistor, three leads, small plastic body. There's one in most throttles. I don't recall the part number but they're not hard to find.

I started with an ebrake lever, which has the switch and is set up to pull a cable. I removed the cable pulling part and epoxied a magnet there. The magnetic sensor was placed near it on a small perf board attached inside the hood. The magnet moves away from the fixed sensor when the lever is pulled. The switch is actuated first with a small movement of the lever, a variable voltage is produced as the lever is moved farther. It isn't set up as well as a good throttle, so the voltage range is less, but doubling the ebrake gain in the controller compensated for it. The controller has ebrake inputs, a switch to put it into braking mode, and a separate analog input for the braking level. It uses regen and reverse current, so is stronger than just a regen. The controller is a Sabvoton. It was adjusted to provide braking just shy of losing traction with the pavement (which it was fully capable of doing). It does quit ebraking at very low speed. Going down a big hill it feels like a parachute. It has ABS like properties, it doesn't skid much though it is close to that point. Reverse current is only used at low speeds and doesn't require much power.

I've ridden my BBS02 for four years of fairly rough off road MTB with a 52V battery, have never even added/changed the grease, but wouldn't consider it for regular commuting. Several individuals have logged 15K to 25K+ miles with inexpensive DD systems and everything should be increased with better motors. You need something like Alan or Mad Rhino have developed (my YESCOM 1000w, 48V project is in its fourth year with no problems, but much fewer miles since used for errands only). Remember though it's not "legal" as a bike in CA.

The bigger and heavier your bike gets the less your leg power becomes a significant factor in the overall performance. You can certainly still put the effort out there, just be aware of the reduced effect.

I would have thought you might want to go in the opposite direction with a lightweight road bike with a minimal booster motor that would help flatten the hills. I guess it all depends on how fast you you need to cover that 30 miles. If speed is key, then a longer bike than can carry the necessary batteries to drive a strong DD motor and have higher stability at higher speeds makes a lot of sense.

You might also want to look at Grin's new GMAC 8T motor. It is a geared drive, but it has no clutch and can do regen. I think the slower wind is what Grin now recommends for cargo bikes.

What Sam Rich said.

For that 35 mph cruise, you really do need a larger hub motor, one that can handle a 1500w to 3000w load for a long time without overheating. Yep, the rig will be heavy, but its quite amazing how nimble a longtail gets when you have a moped size motor on the thing. It won't be as efficient as a mid drive, but it can handle the hills with enough copper wire in that motor.

If you could lower you requirements to 25 mph, then a mid drive would be much lighter, and going 15 mph or less, get up any hill in town.

But as I often say, when you want all that, maybe you should consider what I choose for fast two wheel rides. A 90 mph capable scooter. Yeah, its gas, but at 65 mpg, not a carbon problem.