Electric Bikes - New to Electric guy with questions - Especially high torque geared hub motor?

Okay, I have been an avid bicycle rider since I was just a kid. After I successfully completed the boy scout safe bicyclist course when I was still in elementary school my parents told me I could go anywhere I wanted on my bike so long as I could get back to the house by dinner time and was safe and careful especially on the roads with cars. Thus a bicycle was my first set of wheels and my first true taste of freedom.

This has continued into my adult life and if I have the time to spare I normally prefer to bicycle rather then drive for any local trips. I should start out by being very clear, however, that what I do with my mountain bike many other bicyclists would consider abuse of the bike and/or crazy. Among other things I skid logs out with it ~ No that is not a joke. When I get my firewood for the winter I take my truck and trailer, my bike, and my chainsaw out into the woods and look for nice dry lodge pole and cut them into six foot lengths or so and then skid them out of the woods with my bike to the truck and load up the truck and trailer with the poles. It is a lot easier then cutting them all up into little pieces right there and carrying them out by hand a couple pieces at a time to the nearest logging road that I can get the truck into. To accomplish this I have rigged my bike with a three point hitch assembly with a heavy duty aluminum bar that is just as sturdy as the rest of the frame extending out from the frame over the top of the rear wheel with a ring in the end. And then I have BMX trick type “pegs” on each end of the rear axel that have the ends drilled and rings put in them. I can then attach a three point chain assembly linking to all three of these points that connect to a single ring that I can hook a logging chain too with the other end of the logging chain around the end of the log I’m dragging. I can also hook up any riding lawnmower tractor type trailer to that assembly with another attachment that consists of a rigid, light weight aluminum triangle that attaches to the two lower peg end attachment points with a short cable to the upper attachment to take the tongue weight from the trailer. When I’m not using it for heavy towing (obviously in low gear) that bar that goes over the top of the rear wheel is fairly light weight and serves as a sturdy place to mount anything from a small little rack for holding a couple library books all the way up to fully loaded rear pannier bags with several days worth of camping gear and supplies in them for going back country camping via. mountain bike.

Long story short, I use my bike like a truck not a car. Yes, I commute with it as well just as one can commute with a truck as well as a car but it is set up more for carrying or towing heavy loads with low end gear ratios. Gearing is everything and I lean much more towards sacrificing some speed for the capabilities to carry or pull a heavy load and to climb steep hills. I also strongly believe in a modular system that allows me to quickly add or remove what I need to equip the bike to do the job I need it to do at any given time. Going out to get firewood? Throw the logging chain and link point assembly into the truck along with the bike for skidding out pole lengths. Taking a quick trip a mile down the road to farmer Joes place to get some black dirt for the garden? Throw the trailer hitch assembly on and attach the little dump trailer. Going into town to pick up just a couple small items? Snap the little flat rack onto the rear cargo bar with a couple bungee cords to hold stuff on. Going camping? Throw the rear pannier bags on.

I think you get the basic idea of how I operate. Speed is secondary to load carrying capability and I like to be able to keep the bike stripped down to just the basics and just attach what I need for the job to the bike and not have a whole lot of clutter junk on it that isn’t needed at the moment except what is necessary to allow me to quickly and easily attach what I need at a moments notice. In other words, the rear pegs with the rings in them stay on the bike since they serve as lower attachment points for the towing assemblies and the pannier bags but I sure as heck don’t leave the towing assembly on the bike or ride around with empty pannier bags unless I’m going shopping and they are going to be filled up on the way back.

At this point I am looking to convert my bike to have electric assist capabilities. I am strongly leaning towards a front hub motor type set-up since I would just have two front wheel assemblies and just swap out front wheels to remove the extra weight and complexity of the electric assist assembly for when I didn’t need or want it and put it right back on when I want it. In addition, to the ability to swap in and out would come the advantage of having 2x2 traction which I assume would be sort of like 4x4 on a truck with me peddling for the rear wheel and the motor on the front. I think this would be a significant advantage since I am an all weather rider who has a second set of studded snow tires for his bike as well as chains and I can see the potential for significant traction and control advantages with such a set-up in the ice and snow.

I should also stress that I am not looking to convert the bike to electric power so it is basically just an electric scooter. I enjoy the physical workout and it keeps me from getting fat since I love to eat. What I want is some help on the hills and those terrible nights when I’ve got a ten mile ride home after a 14 hour day in a 30+ mile an hour head wind that is a northeasterner blizzard cutting tracks through snow on the road that bogs me down while dodging snow plows.

What I would really like to find is someone that is selling a tough front hub motor that has a very low gear ratio for very high torque at low speed. Basically a geared hub motor that only had a 5-7 mph maximum speed because it was geared very low for maximum torque to climb hills and buck headwinds without getting bogged down. I think you could even do it with a motor that was less then 500 watts if it was geared correctly for torque instead of speed. It would be nice if the motor had a free-wheel assembly so when it wasn’t engaged it wouldn’t create any drag on your peddling.

I’ve been looking around on the net and doing a lot of google searches. I’ve found some hub motors that say they are geared but so far none say exactly what kind of gear ratios they have and most of what I’m seeing seems to be bent more towards the upper end of the speed spectrum. I’ve been looking for a hub motor advertised as being an assist for climbing hills since I figured that someone out there would have thought along those lines and be marketing a hub motor built for torque rather then speed but so far I haven’t found much.

If anyone on this board could point me in the right direction towards that end I would appreciate it. I did some google searches looking for the most active electric bicycle forum and this one seems to be it.

In addition, most of the hub motors I have looked at are brushless motors that use a special controller unit that also serves as the charger with cell equalization leads for a Lipo battery pack. The big question in my mind is whether those controller units can only be used with a Lipo pack or if they will also accept other power sources as well. I was thinking of doing two set-ups. One with a big battery pack to go on the rear similar to my rear pannier bag set-up with dual packs slung down low just over the axel height to keep the center of gravity low, probably LiFePO4 packs instead of standard Lipo packs since I am not a fan of standard Lipo battery packs since they have a nasty habit of starting on fire in my experience which is not good anyway much less for something that costs as much as they do. And I also wanted to rig up a small 5AH pack made from those super high capacity, high discharge rate 5,000mA sub-C NiMH cells that the electric powered remote control airplane boys love so much as a single pack made up of two or three ten cell packs that could be charged in parallel by any 12V battery charger and in series could provide a couple short 5 minute bursts of 24 or 36 volt power (depending on the voltage of the hub motor I end up getting) that would fit in a water bottle holder. Basically, a cheap little pack that could be easily charged by almost any automobile battery charger and would give me a couple short bursts of assistance on a commute to climb a couple hills and that is all. I understand that NiMH is an inferior battery technology compared to LiFePO4 but in a ten cell 12V pack configuration they don’t need a fancy charger and any old automobile type battery charger will do and are thus more versatile and for a small pack intended to give just a couple short bursts of power for hill climbing on a commute they should do just fine and are probably a better choice then a lead acid type battery.

How about a Xtracycle and Stokemonkey (http://clevercycles.com/products/stokemonkey/)?
The long tail will give you lots of carrying capacity and the Stokemonkey works with the bike's gearing giving you lots of torque.

I love the idea of how the Stokemonkey works through the existing gear system. It doesn’t quite fit into my modular methodology with my existing bicycle though.

I might just end up building a completely separate commuter/cargo bike. I like the long tail idea but I have often thought it would be very usual and unique to have an inline trike with tandem inline rear axels with a set of smaller size heavy duty BMX freestyle type wheels with a cargo rack built around them. For what the long tail frames are selling for I could probably find an old early 90’s name brand steel frame mountain bike swap out the front fork for one that will accept a disk brake and then rebuild the rear end to a custom long tail and do a tandem axel rear end like that with the smaller wheels. Double the drive traction with double load bearing points on tough BMX freestyle rims in the rear, smaller wheels in the rear also bring the rear cargo deck down lower for better center of gravity of the cargo, and of course last but not least the uniqueness factor.

Looking at how the Stokemonkey is set-up I also think one could use an off the shelf rear axel hub motor and just unbolt the side plates and swap them end for end so that the rotation on the freewheel was reversed so the hub drove the freewheel rather then the freewheel driving the hub and mount the hub in the frame by its axel ends and route the top of the drive chain to its freewheel with a down pinch loop with idlers on either side of the hub to hold the chain up tight looped under rather then over the freewheel gear spool with the ability to adjust the gearing ratio of the motor by changing which gear on the freewheel spool it was looped under. It would be a motor up in frame that drove the chain just like the Stokemonkey is set-up only without having to use a second chain on the left side of the crank. Combine that with a freewheel crank set-up like what Cyclone-USA uses in their kits (and also sells the crank freewheel parts separately as well incidentally) and it would work very much like the Stokemoney set-up with the advantage of being able to use any off the shelf controller for the hub motor and not having to have driven petals (not that I’m apposed to the idea in principle but rather it would take some getting used to and makes it a little incompatible to let someone else use your bike who isn’t used to driven petals). Yes, the hub motor would be spinning away on its axel mounted tucked up in the frame which might look a little odd but it would work I think and would allow easy replacement with the ability to drop in any rear hub motor where the side plates could be unbolted and flipped end to end so that the hub would drive the freewheel rather then vice-a-versa as is normally done with a freewheel on a hub.

Sounds like you are in for some experimenting. I love the way you use your bike. Before mountain bikes, we used to use our stripped down single speed Columbia bikes to bring the cows in across the fields in northern MN. I have tried a number of set ups for cargo biking and find the torque on the hub motors to be crap. I have read there are now geared hub motors but the gears may be plastic so make sure they are sturdy for the amount of work you want to do. I stay on the roads with my electric recumbent with an Ecospeed drive that goes through the gearing so I can get as low as any gearing and as high. Ecospeed now makes a version for upright bikes too. They are worth looking at for ideas even if you don't want to spend that much money.
Also check out Endless Sphere for crazy electric ideas, they have some very knowledgeable tinkerers over there.
During my experiments here is one piece of equipment that seems useful but I haven't had time to use it yet. On a normal tandem bike the pedals are linked so the cadence has to be the same for both riders. They sell a crank for converting tandems that has a freewheel device in it that would allow a Stokemonkey to be used more like a normal motor setup. Something for you to look into.
I tried to set up some front hub motors so that they were quickly convertible back to a non-electric bike. I think it would be possible but the wiring that the kits supply is so thin and crappy that you need to plan on beefing that up and enclosing it in a sturdy tube (maybe a heat shrink tube?) so that sticks and twigs won't tear it off your bike. I was so unimpressed with hub kits that I gave up before I got very far on that. You would also be in danger of ripping the front wheel off with that much torque. I am now working on a bike like a dutch style bakfiets that I am making special for my part Corgi (short legs) dog as she is getting too old to trot along side all the time on the way to construction jobs. At the moment I have found using an Xtracycle to be a great tool because it rides like a regular bike but can carry plumbing pipe and 2x4's to my small remodel jobs. I put a Bikes-At-Work 8 foot trailer on the back when I need my tablesaw and compressor and other larger tools. I haven't motorized the Xtracycle. For the type of logging you are doing, a Big Dummy type of solid frame would probably be more appropriate.
As far as small batteries for bursts, you might look into Lithium tool batteries. They probably have an accessory that charges from a car battery. Worse case you could get 3, 12 volt tool batteries and attach them in parallel on your bike.
After my experience, I would suggest you pick up some piece of crap frame from the dump and experiment with welding ideas on to it. Then you can just cut them off and move them or rework them without caring about the frame or how you are beating it up. Then when you get it just right, get a halfway decent frame and do it right.
Good luck and keep us informed if you can.

I would consider getting the hub motor for the back wheel instead of the front, especially if you are using the bike for towing.

At this point from the responses posted here and what I have been able to learn further through the net I don't think anyone makes a geared hub motor that is geared low enough to provide the kind of output I desire (high torque & low wattage use at the sacrifice of speed). It looks like the only way to get what I want is to use a system where the motor drives the rear wheel through the existing gear system to allow access to all the bikes gears.

I do think though, that it may be possible to use a hub motor to accomplish that, I have found several rear axle hub motors that have side plates which can be reversed side for side and also rear hub motors that already come with a side plate with freewheel threads on both sides of the motor where in normal use (installed as a hub inside the rear wheel) one would screw the freewheel on the right hand side of the hub and then screw on a brake disk adapter (with same threads as freewheel threads) to the left side of the hub. The important point with that being is that if you take such a hub without a wheel attached to it and mounted it up inside the bike frame and screwing a freewheel on to the left side of the hub motor rather then the right side then the hub motor drives the freewheel gears rather then the freewheel gears driving the hub due to the reversal of direction from clockwise to counterclockwise when the freewheel is screwed on the other side of the hub. This would allowing the hub motor to serve as a power output motor when not installed inside a wheel but rather mounted in the frame that just needs a conventional bicycle chain attached to it to drive the bike through its existing chain/gear system. This could be done just like the stokermonkey set-up by using a tandem bicycle crank and running a second chain on the left side of the crank to attach to the motor up in the frame (conceivably mounted behind the seat post) or you could just flip the motor end for end and loop the top of the drive chain up to it.

Such a hub-motor with the freewheel installed on the other side of the hub and mounted up inside the frame with an off the shelf hub-motor controller would be considerably cheaper then the actual stokermonkey set-up as sold with its one of a kind motor and controller and would allow much better availability for replacement of either the motor or the controller.

So long story short, I think I will still probably use a hub motor but not inside the hub but rather installed in the frame and driving through the bikes gear system. Obviously, this also means a separate bike build rather then an addition to my current bike. Probably a long tail cargo/commuter since the main reason I wanted a power assist in the first place was for climbing hills or bucking a heavy head wind on a commute especially when hauling or towing a load.

I do not have the time to read such detailed posts but the guy who said Stokemonkey is on it. There is no bicycle front end that can withstand what the o.p. has in mind. Its not the motor, its the bike chassis. Or rather the torque acting through that long lever of bike fork.

H

The Stokemonkey is a hub motor mounted in the frame. He stopped producing it for a while because of some problems. I don't know if they were mechanical problems or some other type of problems. Ecospeed also drives the gears but they don't use a hub motor.

So far this is the best set-up I have found and I will probably end up building something similar:

http://endless-sphere.com/forums/viewtopic.php?f=3&t=25685&start=31
http://urbancommuterstore.com


I also think the Yudo Mundo frame is the best I have found so far for my needs. As I said in my OP what I tend to do to and with my bikes is border line abuse and it appears that the Yudo Mundo frame is built to withstand people like me.