What reliable, low-power motor for 3rd world touring?

Drunkskunk said:
Its nice that you have an opinion on those tubes. Other people have a different opinion based on other facts and experiences. You've had 8 posts in this thread rehashing your opinion. It's time to let it go my friend.



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I am countering their wrong statements about something I have used for 5 years..trouble free...friend.
 
On very bad roads you don't want hard riding tires. Hard means more rolling resistance than compliant tires in terrain. Pneumatic tires lets you adapt the hardness to the terrain. Use high volume tires and deflate and inflate according to the surface.

How much does a solid tire weigh compared to a folding pneumatic tire?
 
tahustvedt said:
How much does a solid tire weigh compared to a folding pneumatic tire?
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Foam tires weigh a little more than pneumatics, and they have more rolling resistance even on smooth surfaces, but that's not why they are bad for most applications. They are bad because they simply don't do the job a tire is supposed to do. Mechanically, they are the equivalent of wrapping a lot of tape around the outside of your rim. They don't suspend the wheel.
 
hjns said:
Hmm, nice challenge! If it is really for assist, I would recommend something like a 8t or 10t geared mac, and try to pair it with a sensor less controller. For low speed application, that should work. Furthermore, a 6 FET controller is small enough so that you could carry two or three, so that this electronic part is not the weakest link. Take two small batteries, so you can partially charge one while driving with the other. You will have a natural limit to your normal e-range on the battery your driving with, while still having the second battery for crisis should this occur.

Don't use a CA or any other computer, it can only break down. Just a simple throttle, with the controller programmed for 15 amps max. Again, throttles are small enough that you can carry two.

Build everything in a modular way, so you can easily swap controllers or throttles or batteries. Don't expect an e-range of more than 15 km and plan your trip for pedal-only, that way you won't be disappointed. ..
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Curious, why would you opt for a 8t/10t mac vs something like the Outrider? It's double the weight, which I'd like to minimize. I think the biggest factor in motor selection will ultimately be reliability. With something smaller like a Outrider I could probably bring a full extra set of internals, but that would be quite a bit more with a mac. I also don't really want/need more than 350w at the most.

I really like your thought of having two swappable batteries, so one can be charging on a fully standalone solar setup. Less integration, less failure points. I also like your suggestion to avoid a CA and just go with a barebones interface (throttle). I'd probably want to have SOME kind of battery monitoring, but that could be something as simple as a tiny voltmeter.

I'm figuring my entire battery would be 8ah at the very most, maybe two 4ah packs... or smaller. I care far more about weight than range. Lifepo4 seems like it might be an appropriate chemistry.
 
I just spent some time exploring the greater depths of the interwebs looking for additional feedback on airless tires. Trying to get as many data points as possible, ya know?

The consensus among people who have tried them out seems to be in line with most of the concerns that have been voiced in this thread. Harsher ride, 2-3mph loss, damaged rims. Sounds like nearly everyone who tried them out ended up reverting to inflated tires. Which is a shame, because on a conceptual level they do seem like a great fit for a crazy middle-of-nowhere trip. But after reading more first-hand accounts, I'm thinking it may make more sense to just get the most puncture-resistant tire/liner/tube combo that I can find and bring some spares.
 
As the miles stack up, conventional liners cause punctures by chafing the tube at the edges and ends.

The most effective puncture protection is to get a heavily armored tire and add a thick thorn resistant tube. It doesn't ride all that well, but it works. Check your tire regularly for embedded objects, and don't overinflate it.

If you need extreme protection, you can get a smooth-treaded belted tire with thin sidewalls-- a little narrower than your outer tire-- cut off the wire beads, and use it as a seamless liner that won't chafe your tube. You'll get a crummy ride along with doubled puncture resistance.

In poorer countries where people run their car tires until they disintegrate, highways are littered with wire pieces from steel belts that are falling apart. These can be a real nuisance for cyclists.
 
I respect the first class advice offered regarding keeping air in a pneumatic tire.

I personally think it would be easier to work on making a wheel survive the added stress of a foam tube replacement. if you can shoot them with a urethane expanding foam or something, perhaps you could find a way to glue in each bead and mount multiple tires thick. No doubt it would ride awful, but it would be awesome to get to ride through wearing out multiple tires only needing to trim off whatever starts flapping.

Alternatively, if you could use motorcycle rims, tubes and tires, you might be better off than the best of the bicycle options.
 
Also, yes, riding across Mongolia sounds awesome.
 
liveforphysics said:
I respect the first class advice offered regarding keeping air in a pneumatic tire.

I personally think it would be easier to work on making a wheel survive the added stress of a foam tube replacement. if you can shoot them with a urethane expanding foam or something, perhaps you could find a way to glue in each bead and mount multiple tires thick. No doubt it would ride awful, but it would be awesome to get to ride through wearing out multiple tires only needing to trim off whatever starts flapping.

Alternatively, if you could use motorcycle rims, tubes and tires, you might be better off than the best of the bicycle options.
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I could envision an airless tire working better with a multi-durometer profile. Maybe a thin/hard center rib and a pair of outer ribs. Fill the remaining profile with much softer foam. The hard center would have a reduced rolling resistance, but if you hit a bump and experienced a dynamic impact (of say, 3x), the center rib would buckle to provide some shock absorption. I dunno, it's a thought.

For this time around though, I'm thinking just spec out some super puncture-resistant tires and tubes and bring some extras, and maybe some tire goo.

Kinda torn on the brakes thing too. A v-brake seems like it has less failure points, but it could still fail somehow I'm sure. I'm guessing an extra caliper/cable doesn't weigh too much. The disk brakes would sure be nice on long downhills, especially with all the cargo weight.

Still trying to think about motor choices. It seems like the Q100H/C and Outrider are good candidates, don't know much about the Leaf or MXUS unit. Not understanding enough about the differences in internals - is one of these geared hubs inherently more serviceable or reliable? The Xiongda would be neat but I'm afraid the additional mechanisms would add additional failure points. Direct drive is heavier and doesn't seem as well suited for climbing. Mid-drive could be a good fit. I'm thinking it's a toss-up between [the best geared hub motor] and the BBS01

The present list...
Q100C or Q100H
Outrider
Leaf geared hub
MXUS geared hub
BBS01

I'm rather excited to get the motor aspect figured out because I'm ready to start shopping for a suitable used bike for this swap. I've been needing something comfy for getting around anyway - my little road frame is putting too much weight on my wrist.
 
Very few riders are happy with airless tires. They belong to carriage harware and antique IMO. Not so hard to make a reg tire reliable, and to carry some slime for emergencies.
 
I think the mid drive would be a less good choice for really primitive conditions, if the chain breaks or something goes badly wrong with the drive you are stuck with no ability to move under pedal or electric power,with a hub motor even if the chain breaks you would still be able to roll under electric power. Also I think a small hub motor would be easier to make reasonably stealthy visually than a bottom bracket drive.

I have a Bafang geared rear hub not a lot bigger than the Outrider and it's been reliable in my usage (mostly smooth street but up and down a long and steep rocky dirt driveway every time in and out) for thousands of miles so far, I have a direct drive on another bike that's a good bit faster now but the Bafang was retired in good working order still.

If a hub drive quits even if the motor is flambeed and clutch is seized you can strip out everything but the bearings and still use it as a regular hub. If the custom parts in a BB drive fail changing everything out is quite a task with a whole different set of major parts.

It also occurs to me that a torque throttle rather than a speed one might be preferable, the right controller should be able to keep you from burning up the motor at low speed high load conditions which is where it will want to get hot. In a 29" wheel getting a low enough gear for that grunt use is probably the most important factor in practical useability. There's a tradeoff in wheel size with the motor too, all else equal smaller wheel makes more linear thrust down the track but at a slower speed but a bigger wheel goes over and through stuff better.

If you go here you can play with different situations and see how some different motors will respond, the Outriders are in there.. At max amps on the Outrider you are only going to get at most a few minutes of thrust up a steepish slope before the motor overheats. In a hot climate that will probably be worse, hopefully you don't have enough battery to do the job properly and the motor just smells funny after. :)

http://www.ebikes.ca/tools/simulator.html
 
Aw shoot, I totally forgot that the BBS01/2 is all internal gearing. For some reason in my mind I had been equating it with something like a GNG/LightningRods kit, where you could just remove the chain if the motor crapped out. I still think a mid-drive could be advantageous for the gearing benefit if I went the route of something that uses a chain and tandem BB, especially after playing with that calculator (thanks!) and seeing that the geared hub motors I'd been looking at will likely overheat quickly on an uphill grade.

Are there any mid-drive kits in the 350-500w range that use an external gear reduction like the LightningRods kit? The power handling of that motor seems pretty overkill for my purposes.

Looks like if I want to keep with a geared hub I'll have to investigate the next size up from the Outrider/Q100 to combat thermal issues. Weight/reliability are still at a premium though. Back to trawling the forums for info...

I'd really like to keep with the 29" wheels if at all possible...
 
A Stokemonkey type drive probably makes the most technical sense for what you want to do but that is far from stealthy and requires some custom frame work. Perhaps an Outrider driving the chainring Stokemonkey style would be an option, you could probably fit a small geared motor in the triangle of a more or less standard frame and there is also a small diameter DD motor available that might work for that sort of drive..

http://www.conhismotor.com/ProductShow.asp?id=84

If you plan on getting much steep slope climbing ability out of an 8AH 36V battery the gearing is going to have to be really low so the motor can spin up and keep the amp draw down, you can play with wheel sizes in the simulator to give the effect of different gear ratios for the motor. For a 29" wheel if you set wheel diameter at 14.5" then that is equivalent to a 2:1 chain drive to a 29" wheel, a 10" wheel size would be equivalent to 3:1 drive and so on.

For instance with the 29" wheels and 220 lb total weight if you had a 3:1 gearing from an Ezee geared motor from ebikes.ca to the wheel (10" simulator wheel size) you could climb a 15% grade for 3.3 miles at ~7 mph on 8AH without pedaling and the motor would not overheat..

With the Outrider you would need an even lower gearing 3.25:1 (8.25" wheel size in simulator) and your speed would be closer to 5 mph but you would get 3.2 miles of 15% climb out of the 8AH battery and no motor overheating, again without pedaling.

Add 150 watts of pedal power to the second system and you could climb for about an hour at just over 5 mph for 5.2 miles of 15% grade on your 8AH 36V.. 150 watts pedal power for an hour in a tropical climate is likely to overheat you though.. :)

The Xiongda 2 speed motor would probably be closest to ideal for your application but reading the thread about it makes me wonder a lot about the long term reliability of that system, if the manufacturer keeps on developing it I don't see why it couldn't be reliable but it doesn't seem to be quite there yet, I came very close to buying one of those systems last year but after several emails back and forth to the manufacturer finally decided on a 9C clone instead.

If it were me I'd probably opt for the small DD motor driving the chainring Stokemonkey style with the lowest ratio I could manage and count on spending some time fiddling with with the mechanicals during the trip. But I'm a bit of an artful bodger and I would find making field repairs almost entertaining...
 
Jonathan, thanks so much for all the information! Especially for holding my hand through usage of the motor calculator in a mid-drive setup.

What's making the most sense to me at this point is using a small geared hub stokemonkey-style to the bb. I looked at that dd hub but it's about double the weight - at that point I could just carry an entire extra motor with me. Much larger diameter too, for what that's worth. It seems like a lot of the small geared hubs are fairly well developed and reliable at this point.

To run a fwd motor like the outrider, I'm guessing I'd have to kludge some method of attaching a chainring? Using an adapter that ties into the disk brake threaded holes makes the most sense to me, from what I can see in pictures of the motors. Then a simple custom frame mount for the motor axle. I'm guessing I could avoid the chainring kludge if I went with a rwd motor that can accept a freewheel, like a Q100h?

For the batteries, I'm thinking a pair of 10s3p packs could work well, so I could have one charging while the other is connected. Sounds like I'm looking at close to 5miles of 15% climbing ability per pack while pedaling - pretty good if you ask me.
 
I'm not a good one to talk to about batteries, all my experience is with salvaged 18650 laptop cells since I have a connection for getting them in moderate quantities at low/no cost.

I'd forgotten how heavy that DD motor is..

There is probably going to be an issue with the clutch when trying to turn a rear geared motor the wrong way for a Stokemonkey type setup, the disk adapter for a sprocket on a front motor is the more straightforward solution. A freewheel in the crank chainring is just asking for problems under primitive conditions where all kinds of crud are likely to get into it so you should leave that out and just pedal any time the motor is on. Pedaling the motor when it's turned off shouldn't be much of a problem though because it does have a clutch in it to allow freewheeling in the forward direction.

Problems with ingress of contaminants aside a Stokemonkey type setup shouldn't stress the motor much if you are keeping the revs up and the amps down. Reliability of the motor and controller should be good if you can keep the crud out of them.

If you know what your normal comfortable cadence range is you can work backwards to figure out the gear ratio needed between motor and cranks, the simulator can be set up to give you an rpm reading rather than mph or kph. I spent a lot of time playing with the simulator last year figuring out my latest bike before I built it and my measured numbers come within a few percent of the estimates I got from the simulator.
 
I run a MAC10T as a commuter pushing over 2kw... over 5000km of riding so far, so I can say it has the reliability stakes in the bag.

The other good parts... I'm on my original Schwalbe big apple. I've pulled wires/thorns/rocks out of that thing and it's been pretty solid as a 2" wide balloon tire. The tread is pretty much all gone down the centre though. 5000km aint that bad.

The bad parts... Chewing through disc brake pads with repeated stop/start on commutes. Taking a hub motor off is a pain in the ass. There's no other way to describe it. Cut the cable ties, take off the torque plate, undo the bolts etc. I was using shimano organic for the zero squeal factor but they don't last long at all. I'm using Nuke Proof Enduro sintered pads now. Seems to last longer than 2 months.

There are no quality freewheels in 9 speed 11T. I don't know if its because I'm heavy or its a 29er, but I'm smashing drivetrain parts. First one was the pedal... pretty much the same as the one Kiriakos posted before. It snapped down the middle. Giant MTB Core pedal with screws is 100x better. 2nd drivetrain failure was the freewheel. Stripped the ratchet in gears 7/8/9. Lucky the MAC motor is strong enough to just ride like a motorbike for a week while waiting for replacements...
 
Raged said:
There are no quality freewheels in 9 speed 11T.
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Since Shimano's 11-34 and 11-28 7-speed freewheels went out of production many years ago, there are no quality freewheels with 11t sprockets at all. And that's really just as well, because running in your 11t more than once in a while wears out your chain, which in turn wears out your other sprockets. It's actually a blessing in disguise that better quality freewheels have a 14t small sprocket.

Mechanically, the right way to get high gears is with large chainrings, not small rear sprockets. In my pedicab fleet, we use "road triple" cranks with 52-42-30t rings instead of the more common "mountain triple" cranks with 42-32-22t. Then we do a reduction on the second chain stage (with heavier industrial chain) to get the gear ratios down low where we need them.
 
Ok, here's a new functional requirement to throw at this project: the battery system must be capable of charging under pedal power.

As far as I can tell, a stokemonkey-style setup should still work fine, but with a small direct drive motor instead of geared. I'm thinking maybe the NSM, as it's pretty light/thin/compact. As far as I can tell though it doesn't have disk mounting holes, so I'd have to kludge up something else utilizing the spoke holes (or...?). It also seems like the NSM is targeting a smaller nominal wheel diameter so I'd have to adjust the motor->bb gear ratio accordingly.

The idea is that the bike can be propped on a center stand and pedaled to charge the batteries when solar/other is not available. This is actually less critical to my planned solar voyage and more relevant to a friend's effort, which involves providing power in the 3rd world backcountry for 12v things (via a dc-dc) like lighting and cell phone charging. Or the bike could provide a micro job opportunity for some local kid who will pedal-charge your battery for you.

I'm increasingly convinced that a hub motor being used on the wheel is the wrong choice. If *anything* fails, I want the bike to absolutely be able to revert to normal bike status. The gearing advantage of a bb-drive is a big factor too.

The only real alternative concept that stands out is a friction drive of some kind. What do you all think of those? Can they be made reasonably reliable in wet/muddy conditions? On a fat-tire bike? My understanding is that they already benefit from some gearing advantage. Are there other pro's/con's that I should consider? I don't have a very good sense of which friction drives are well-regarded on ES...
 
Zymosis said:
I'm increasingly convinced that a hub motor being used on the wheel is the wrong choice. If *anything* fails, I want the bike to absolutely be able to revert to normal bike status. The gearing advantage of a bb-drive is a big factor too.
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Two observations:

I have never seen any crank drive setup that is exactly a normal bike once you subtract the motor. Some of the not-normal bits like freewheeling cranks are by an order of magnitude the most likely parts to fail. If you think an unpowered hub motor is a show stopper, just try a freewheeling-both-directions crank.

When you apply greater-than-human power through gears designed for only-human power, things wear out and break at a substantially accelerated rate. That might be an acceptable compromise when you're near your parts pile, your local bike shop, and your FedEx guy. Not so much in Botswana.

EDIT: A non-freewheeling Stokemonkey type crank drive more or less avoids the pitfalls described in my first observation. It's still very much subject to the increased wear and breakage I describe in my second observation.
 
After having two bikes stolen I'm all about the homeless bike look as a fashion statement and peace of mind. 14 or 13/14 spokes, no 12ga. Plus a few spares. I like slime thick tubes, but I run a rear hub.
 
Run 2 sets of anderson connectors off your battery. Off this, one set of andersons go to the controller and the other set is loose so you can plug in a DC-DC buck converter for 12V (should be about $16 from ebay) So you dont need to unplug the controller to use it. Off this buck converter set to 12V, have a 12V ciggie plug where you can put in a USB 2A charger or power any 12V accessories you need to run. So you now have 12V and 5V power to run any of your stuff. Ciggie plug is so you can plug in any other automotive plug like a small air compressor... And USB so you can charge your phone if you get lost (like I do ALL THE FRICKEN TIME IN THE MOUNTAINS... =)

I sorta do the same for a camping setup to provide power to remote sites.

Edit. Come to think of it... is there a reason you cant use the charge plug to power accessories?
 
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