electric worksman front-loader cargo trike

[eobanb]

Hi all,

This is my first post here so I apologise in advance if I run afoul of any conventions. To get right to the point, about a month ago I acquired an old Worksman model STPT, which is a front-load cargo tricycle. It was previously used in a Ford transmission plant in Indianapolis that recently closed; I got it quite cheap from a nearby bike co-op.

Anyway, some of it was pretty damaged—I've replaced the front axle and some of the bearings, which at least got it rideable. The rear single-speed coaster brake wheel was badly bent, and so yesterday I replaced it with a new (old) Schwinn S-6 wheel with a Shimano 3SC hub (three-speed hub with coaster brake). For some visual context, here is the complete trike from a few days ago, before I replaced the single-speed wheel:



Here is the new three-speed wheel:

The trike rides well on flat ground, but unfortunately it is quite difficult to pedal uphill even in low gear. I would guess it weighs about 100 lbs unladen, and the steering dynamics don't really allow the rider to stand up on the pedals. Right now I live in a pretty flat neighbourhood, but in August I am moving a few blocks away up a hill. This seems like a perfect opportunity for a modest electric conversion. I am not looking for speed here, I am looking for torque. The sole point of this conversion is to be able to go uphill, not to keep up with motor traffic. Going more than about 12 mph on this thing would be suicide anyway. So begins my search for a decent but cheap electric setup.

Some things to know: there are no braze-ons for racks, fenders, or anything else; in fact it's not even drilled for a rim brake. Fortunately there is plenty of clearance for just about any sort of 26" wheel—I already had to bend it out a bit to fit the three-speed hub. I figure that because of the design of the trike, an electric conversion will almost certainly have to be a rear wheel hub, and the battery pack and controller will be stored in the front box (the front box is rated to hold 500 lbs, so this will be no problem). I think I'd prefer a pre-built wheel over a bare motor.

Apart from these constraints, I am open to just about any recommendations people have with regard to amperages, voltages, motors, controllers, and batteries. I assume something mid-range, (like a 36V / 500W system) would work fine? I once owned a cheap 24-volt Currie eZip electric bike about six years ago, but apart from that, my experience with electric bikes is limited.

Thanks!

 

[Drunkskunk]

Welcome to the forum. Nice bike!

A hub motor would be problematic with that build, as you would lose your only brake. The motor replaces the hub, and the coaster brake is in the hub. Also, routing the cable for a hand brake might be a problem because of the whay the steering works. Routing the cable without kinking it would mean a very long cable run.

The solution is a mid drive, like a Bafang BBS02 or a GNG drive. those get pricey, but run the motor through the gears and allow you to retain the coaster brake and rear hub. Also, a mid drive will have the highest torque of any type of conversion. There are some cheaper kits out there as well that might work, but would be more labor and maintenance intensive.

 

[eobanb]

Thanks for the advice, Drunkskunk.

Two issues I see with mid-drive is that the frame continues straight to the front of the trike from the bottom bracket rather than rising up in a triangle shape as on a conventional bike, so I'm not sure a mid-drive like the Bafang would fit, unless the motor itself were down below the bottom bracket instead of in front.

Second issue is cost. A Bafang kit alone is $550, plus a LiFePo battery pack would probably be $400, bringing my total cost to $1000. Unfortunately I'd like to spend about half that. I agree that mid-drive kits are probably the future, but I think for now I'll need to go with a rear hub.

As for the brake setup, I will probably just install some means of adding a rim brake, such as with this $25 gadget https://www.danscomp.com/products/489051/V-Brake_Plate.html . I have seen that kind of thing done with other Worksman trikes.

 

[Drunkskunk]

That brake bracket would work. they also make something similar for disk brakes, and most hub motors have mounts for them. the price difference in setting them up is probably about the same. there are also some cable operated band and drum brakes that might work. You could even bolt on a piece of scrap angle iron or flat plate, drill 1 hole, and add one of these style rim brakes. http://sheldonbrown.com/images/caliper-600.gif
Lots of possibilities. Most will work with bolting on, but be better if you can get them tack welded to the frame. But all have cable routing issues. a super long cable is going to be spongy.

If you're set on a hub motor, check with member Dogman Dan here on the forum, he may have a lead on a low RPM motor that would be better for that kind of trike, a normal hub motor would be too fast. If operated at slow speeds and under load like that kind of trike will be rode, it could overheat. I think a company he works for sells a motor designed for trikes

The BBS02 is the top end. The GNG run ~$200 cheaper, but aren't as seamlessly designed. Having the "downtube" be horizontal shouldn't be a problem, it would just move the motors a little lower, or alternatively, higher and above it.

 

[dnmun]

maybe save that trike for another use so find a real bike and build a real ebike which would allow you to use a regular hub motor and battery.

this thing should not be used for an ebike since it is too heavy and unsafe at any speed.

 

[dogman dan]

Hmm, How steep a hill? I could see how stopping it coming down the hill could be a much bigger problem than the motor to go up.

I'm actually starting to wonder if something like the Ezip you had before might not be such a bad idea after all. They are torquey things, and could be added to the existing rear wheel couldn't they? If the hill is not so long or steep, a 36v one might have enough power to get you up it without overloading it to death.

A mid drive might still be a good solution? Maybe a GNG kit if a Bafang cannot work slung under the frame.

Anyway, that keeps the brakes foot activated which seems a good idea. Lot of welding to do front rim brakes, lot of cable and a pretty strange routing to add a rear rim or disc brake. Some kind of handle down by the seat could work, but then you have to take one hand off the steering just when you need it most.

In any case, what a great collectors item bike you have. That worksman really worked! Love the F 5 brand on it!

 

[cjh]

The freewheel in the Bafang won't let the coaster brake work.

 

[dogman dan]

Ahh, of course. That makes sense now that I think it through.

Sort of takes you right back to this again. (same motor you had before) I think you could make one of these work on the coaster brake wheel.

http://www.thesuperkids.com/cueldrelbico.html

Do you weld at all? A frankenbike setup that uses a motor to drive the rear wheel seems like the best thing you can do.

Second sprocket on the other side of the wheel sort of thing is what I mean, but it could be a bigger motor than the currie kit.

Or something with no freewheel. Second sprocket on the pedals, so a motor will drive the pedals. Hit the throttle, pedal or get your ankles whacked. So like a GNG kit, but omit the freewheeling front crank part of the kit.

 

[2old]

Look at identiti forks V Brake adapter for one possible solution although other companies make a similar product. and you could fashion one yourself by welding posts to a split clamp. This device clamps on the frame or fork and allows V brakes or calipers to be mounted.

 

[gogo]

A 9" diameter hubmotor mounted underneath the seat area and used as a friction drive. It would be super cheap, quiet, wouldn't upset the dynamics of the trike, and would operate with high torque at trike speeds.

A pivoting friction drive would allow the motor to disengage when unpowered by gravity causing it to rotate forward. You could make it lever operated with a spring to have more control over engagement. The pivot arms could be made from the rear stays of a donor bike.

 

[daddz]

looks to be enough room behind the seat post to mount a cyclone motor, but you would need to make sure the gearing is matched to what you want.

 

[JoyRiddin]

What about a front geared hub motor or two?

 

[eobanb]

Hey all, just a short update for now. I decided to order a Danscomp V-brake plate just to see if that works; I figure if I use either a mid-drive or a hub motor, the coaster brake is going to have to disappear, so ensuring a V-brake will work keeps my options open.

I checked Worksman's site to see if they offer electric; unfortunately they only have front-wheel options for their delta trikes (like the Adaptable).

Doing a Currie-type chain drive solution occurred to me (especially since I have prior experience with that) but my instinct says no. It's really a last-generation type of ebike system and I clearly remember it didn't offer much torque even on a regular bike. It's also kind of loud.

Friction drive sounds interesting but I think it would probably take a lot of DIY, potentially slip a lot, put extra wear on the tire, and probably look kind of messy in the end.

I took a test ride on Tuesday with roughly 200 lbs in the front box on a nearby rail trail (very flat, perhaps a 1-2% grade maximum). Even on a very modest hill, it got pretty tiring in first gear on the three-speed hub. I did find that if I get a 'running start' I can get up a fairly steep hill if the box is empty. I'm getting fairly good at riding this thing. It's still not quite as intuitive as regular bike, but once you're at speed, you can really cruise on flat ground going straight.

On Saturday I'll be heading to the local bike co-op to find a suitable V-brake to mount to the Danscomp plate and at that point I can test out how well it works for braking downhill before I commit to a certain type of electric.

Side note: I think it would be hard to do anything with the front wheels, whether electric or brakes.

More updates to come.

 

[eobanb]

Another update:

I went again to the bike co-op where I had found the trike originally in hopes of seeking out some other trike parts. Fortunately I was able to find a rear rack that mounted directly on to the rear axle, which should be of help in carrying the controller, batteries, tail light, or whatever else I want. This was something I was worrying about a lot since the front box I want to keep available for cargo, plus the box is some distance away from the rear wheel.

I also found a suitable V-Brake and mounted it to the Danscomp plate, but I did have some trouble finding a suitable brake lever. Almost every bike brake lever clamps with a single bolt and is designed for a certain diameter of handlebar, but the trike handlebar is considerably thicker than a regular bike bar. I was faced with either trying to find a motorcycle brake lever or figuring out some other braking method. Fortunately I did manage to find a double-bolt clamping lever, and it even has a parking brake feature (it's just a little button you push down that keeps the lever pulled). I haven't actually hooked up the brake yet (it seems I might need a longer cable than usual, maybe one designed for a tandem) but I'm getting closer.

I'll try to post pictures of this stuff tomorrow.

In other news, I used veloroutes.org to calculate the actual percent grades of nearby hills, and they're actually not as steep as I believed. There are a couple of hills in my neighbourhood that I figured were at least 8 or 9% but even the steepest hill I can find is barely 6%, and these sections are only about half a block in length and fairly easily to avoid—the route from my new place to/from the nearby flat trails maxes out at 5%.

A friend of mine agrees I will probably want to look at a 500 W motor if I expect to be able to go up a 5-6% grade at about 15 km/h. What I'm wondering is, how much does it matter if I go with a gearless motor versus geared? Obviously geared will provide more torque at the expense of speed (which is what I want) but most geared motors are lower wattage.

Can anyone recommend a rear-wheel 36V 500W geared motor/controller kit?

 

[Drunkskunk]

For that bike, the best geared hub option is probably the 10 or 12 turn MAC. http://em3ev.com/store/index.php?route=product/product&path=36&product_id=107

 

[eobanb]

Just a few more pictures from the other day.

Trike



Rear rack basically fits



Brake plate and V-brake



Peregrine BMX brake lever



Rear rack (probably will hold some electric stuff)



Still need to hook up the rear brake but it's getting there.

 

[ddk]

where did you acquire the vbrake plate?

inquiring minds and all that...

 

[MadRhino]

That is a good candidate for a front build. I mean, with that big cargo bin, you could hide everything on the front and leave the rear neat.

For brakes and mud guard, easy to weld mounting tabs on this steel frame.

 

[CaverX]

I am wondering how you have progressed on this project. I also have a Worksman Frontloader that I want to use for an art project. As I will be carrying quite a bit of weight in a difficult environment, I am thinking of adding electric assist.

Here is the only apparently complete conversion I have found so far, Sorry, it is a Facebook link... https://www.facebook.com/electricbi...8621521624929/629710183849395/?type=3&theater

 

[housegreening]

Hello all - i'm the owner of the electric conversion that CaverX linked to on FB. I came across this thread while searching for info on installing a rear disc brake because my direct-pull cantilevered v-brake setup is not working out very well.

At top powered speed (~8mph), it requires 15-20 feet of braking before stop. Not even close to enough stopping power. I've since lowered the governor on the motor to 6mph resulting in a slight improvement.

It's also proven difficult to keep the brakes adjusted properly. Everything is as tight as possible to get the most stopping power and the pads tend to rub the rim, thus stressing out my motor.

This is one heavy trike with a full load! I'm putting my employees (most young ladies) out on the street with this thing and I can't sleep some nights for worrying about their safety.

That all being said, mine has a full cargo box which adds a considerable amount of weight compared to eobanb's platform. A v-brake system (properly tuned) may suffice for him.

For anyone interested, here's a closer look at what modifications i've (with the help of a welder buddy) made to this trike.

1) Welded cantilever bosses to the seat stays: http://www.niagaracycle.com/categories/rear-canti-boss-with-3-spring-holes-bag-10 The adapter option doesn't look beefy enough to me.
2) Mounted 110mm v-brake system with dual-compound 72mm pads. I've tried two different sets now with no difference in performance.
3) Fabricated support bar to mount stem and handlebars. This was necessary in order to use a conventional brake lever and other handlebar accessories. Has also greatly increased comfort and control.
4) Routed long brake cable through cabinet and down to frame at center of front axle. With a little slack this worked out very well.
5) 36V 500W Direct Drive Motor Hub from Jason @ http://www.electricbikeoutfitters.com. ~20 mile range and will carry my ~200lb a** right up a hill no sweat.

Happy to answer any questions and would love to receive any advice on proceeding with a disc brake system. Thanks!

 

[ddk]

...

1- check with your motor supplier about regen or ebs braking for the motor. Regen brakes coupled with the v-brake should work "not just good... just good enough!"
2- I use either light gray-colored pads or koolstop pads on v-brakes and they work pretty gud compared to the other pads. The light grey pads wear quickly but stop faster than the koolstop salmon-colored pads, with both of them providing better action than other pads. Nowadays I just use koolstop pads with regen brakes.
3- on the trike I use that has no regen brake capability (geared hub motors) I use disc brakes in conjunction with a v-brake. The disc brakes need attention every few months but otherwise work well

Distributing braking to more than one wheel, particularly to the front wheel(s) will get you the best braking action. Consider adding discs to the hollow hub rims wheels or replace them with disc compatible wheels. Welding will be required.

 

[Drunkskunk]

Hello all
...
Happy to answer any questions and would love to receive any advice on proceeding with a disc brake system. Thanks!

Welcome to the forum. I like that handlebar mod.

A disk brake would be easy enough considering you could fab that handlebar mount. A disk brake mount is nothing more than a piece of bar stock, welded to the frame, with a couple holes drilled in it. You would also want to add another piece of stock between the seat stay and chain stay near the brake, to help distribute the load and keep the frame stiff around the brake.

However, that's not what I would recommend. Maximum braking force is achieved at the point just before the tire begins to skid. Therefor, any brake that can skid the tire is capable of the maximum braking force and the shortest possible stop. Any brake that can't skid the tire belongs in the waste basket, as they just aren't safe. The larger the disk, the more heat they can dissipate, and the finer control you have on modulating your brakes. What many people don't realize is that a rim brake is a giant disk brake. Instead of a 160mm, or 185mm disk, a 26" wheel is a 559mm disk brake.

Yes, there some good reasons for wanting a brake disk independent of the rim, but for a heavy cargo bike with only one braking wheel, the best brake is the rim.

If your brake is not skidding the tire, I'd suspect it's the cable. Long cables and tight curves like that make for poor brake performance. Switching to a disk brake wouldn't cure the problem. What you need is to eliminate the cable.
The answer is hydraulic brakes. hydraulic lines don't lose pressure over long runs, and can handle curves around the forward steering pivot like your line needs to do. Hydraulic rim brakes exist, and would do well for your bike, like these from Magura: www.chainreactioncycles.com/us/en/magura-hs33r-brakes

If you can skid the tire but aren't stopping well enough, then the problem is your tire. Since it's the tire that actually does the stopping, you need better contact between your bike and the road. a wider tire, a softer compound, or better tread for the road conditions can all improve your braking performance.

 

[WoodlandHills]

Before I altered anything, I would change the cable to a Jagwire setup and see if that makes a difference. On a long cable any compression of the sheath/housing or stretch of the cable will be noticeable......

 

[Chalo]

Before I altered anything, I would change the cable to a Jagwire setup and see if that makes a difference. On a long cable any compression of the sheath/housing or stretch of the cable will be noticeable......

While that's true, a V-brake system minimizes this effect by moving the cable through a longer distance at a lower force, compared to most other brakes.

Just a guess, but I suspect the OP may not be using a V-brake specific lever. If you use the wrong kind of lever with a V-brake, you get mushy feel and easily run out of lever travel before maximum braking is reached.

If I were trying to improve braking on the OP's trike, I'd consider fabbing a pair of spoon brakes or plunger brakes for the front tires. Braking power will never be good if the only brake is on the rear wheel.

 

[WoodlandHills]

Good points, do you think a brake booster will help?