Hello all

[ReclaimedCycles]

Hello everyone. Was referred to here by bikeforums.net

I operate a not for profit organization that takes bicycles that have been thrown out or abandoned and recycles them back into the community so they can be used again.

I am brainstorming right now about a bike trailer that I will assemble to carry several bikes from the dump. The problem is that I can easily see 100+ pounds being carried and there is a significant grade up to the dump site (think 30-35%, huge incline).
My legs can only take so much so I need some assistance from some type of electric motor.

I'm looking for some solution that is cost effective. As you can imagine, our organization has a very tight budget. I really want to see this happen though as I will be able to transport a whole lot more bikes for later refurbishment.



Thanks for any input

 

[xyster]

Welcome. So am I correct in assuming that you can't get from the dumpsite with a car/trailer or pickup truck, but you could use, say, a small electric scooter or e-bike towing a trailer?

How far would you need Device X to haul these bikes?

 

[ReclaimedCycles]

Its possible to get to the site with a car but I don't own one and like to do everything I can solely by bike

The site is about 6 miles from where I am. Most of the route has only gradual hills and the route back home is mostly downhill. The problem area is that steep grade at the entrance to the site. Its probably only 1/8 mile long but its sharp

 

[TylerDurden]

Greetings,

As much as I admire the goal of an end-to-end bike process, I would suggest a car/trailer or truck; mostly on the issue of the dump being murder on tires. Car tires are bad enough with the sharp debris, but bike tires....? Yikes.

If you are determined to proceed with bike trailering, I suggest rigging a team/tandem rig with two bikes joined at the sides and two riders (four wheels). If this is a community program, get the community invested... volunteers can help you do the pickups at the dump using your team/tandem setup.

( perhaps put solid tires on the trailer, too)

 

[xyster]

Yours' is a tricky problem because there is no off-the-shelf small EV solution that'll pull a 100lb trailer up a 30% grade. It can be done, and a few of us here have bikes and scooters that could probably do that, but it'd take a kit, it'd take modifying some components of that kit, and it'd take carrying in the trailer or on the vehicle either a lot of very heavy batteries, or very expensive batteries to provide the power necessary.

If you could verify this hill's steepness, you might find it's much less than 30% (very easy to overestimate grade). And if it is, then this project becomes much more doable with a small electric vehicle on a limited budget.

Pedaling two connected tandems up a 30% incline doesn't sound doable at all though as it'd take at minimum 3000 properly-geared watts to move 4 people and 200 lbs of equipment up a 30% grade at a few mph.
http://www.kreuzotter.de/english/espeed.htm

 

[Mathurin]

Hi, excellent idea!

I'd suggest starting with a tricycle, it would allow going very slowly while still going onwards, and I expect this is going to happen pulling a large load up a 30 - 35% grade, that's steep. A trike makes it more realistic to carry lead batteries for the job, imagine hauling a cinder block on a bike and you get the idea... The advantage lead batteries have is that they're really cheap. A motor that drives through the trike's gears would allow both reasonable speed on the flat and the ability to crawl up that hill pulling a heavy load. Also by virtue of the space available on a trike, it should be possible to make do with junk parts for motor / drive train, so that would reduce costs also. I'm thinking some brushed motor + cheap controller + throttle. I'd expect this setup would attract attention though, so it would be a very good idea to check the laws where you live. You've not posted your location, but for example if it's in NY it would kill this project in the egg...

 

[Mathurin]

I was thinking something kinda like this, in a lighter/more bike-like way though.

 

[CGameProgrammer]

If the road truly were a 30% grade, in 1/8 mile it would go up almost 200 feet, the height of a 20-story skyscraper. Is that accurate?

In any case, please give us some sense of budget. Any electric bike will at least make the job easier by alleviating the load, and even the weakest ones still produce more power than you likely do. The most powerful motors (2000 watts) can definitely handle the job themselves without pedaling, but they're not cheap; one retailer sells a complete pre-wired kit for $1000. Weaker motors and batteries are cheaper, perhaps half that?

According to the above calculator, 2000 watts ought to allow you to do it at 9 mph, if the weight of you, the bike, the electrical components, and the cargo all totalled around 350 lbs. But 30% is ridiculously steep.

 

[Geebee]

You guys are over complicating it, put a geared 750w unite cheapo motor driving 1 rear wheel on a trike through a 6/7 speed derailleur set to allow super low speeds.
Drive the other with the pedals again with low gearing, that way you have 2 wheel drive on the steep stuff. put the sla'a over or under the rear axle for traction and stability
With the above setup you should be able to tow a car on the flat.
If you are willing to go slow up the hill you could even do it with a 250w setup with pedaling.
The trike could be built with 2 rear triangles out of bikes, so you get the derailleur mounts etc. all set to go, 20" wheels would be a good move as it will give you a good start on low gearing and there are lots of tyre options. Plus a trike will give you the option of brakes on all 3 wheels.

 

[Mathurin]

what 30-ish degrees looks like

http://lawheelmen.org/fargo.htm
http://vmac.smugmug.com/gallery/445104/1/17909643

Story about it
http://home.comcast.net/~wymanburke/FargoStreet.html

 

[numberonekiwi]

and here is a very steep hill claimed in the guiness book of records as being the steepest in the world

http://scasagrande.tripod.com/NZ3b/

 

[xyster]

From the Fargo street site, a thousand words:

A much steeper slope, rise over run in negative territory:

 

[Geebee]

I just tried the figures for the trike setup I described above and it should romp it in.
Even allowing a 100kg for the trike and load about double what the OP specified a 1000w (750w motor 250w human) would climb at 7 kph, and that is running the motor at its continuous rating.
If the road is actually 25% the speed will almost double.