Several years ago, when I was getting into biking again (50 years after biking at college), I got a Downtube viii h for my birthday. http://downtube.com/images/2008_Bikes/8H/8H_Standing.jpg
It's a 20 inch wheel folder, aluminium, with hub gears; an 8-gear Sturmey Archer gearbox. The nice thing about that sort of gear, is that you can change gear while stationary. I rode it for about a year, and then realised I wanted an electric bike. And when I got one, it went into the shed.
A few years (and a few bikes) later, I had a Synergie 20 inch wheel rear hub motor electric bike, which was very nice until the frame just broke apart while I was stationary (I hate to think what would have happened if I'd been zooming along in heavy traffic). I took the broken bike home, put it in the shed, and I've been using it occasionally for spare parts on my other Synergie, bike.4.
So I had just destroyed bike.4's motor wheel; expert opinion says that the internal gears have broken, and I don't think that this is fixable at any price lower than what a whole new hub motor would cost. Downer.
And then I got to thinking. I have that Downtube, which actually looks even prettier than the picture posted (suspension front but not rear), and I have the motor wheel from the frame-broken Synergie, what if ...
So I did. First I checked the front forks. The bike is aluminium, but the front forks are, hurrah, steel! And anyway, I put on two torque arms. So the project is feasible. The inner tube on the motor wheel had perished from age and disuse, but I prefer thick thorn-resistant inner tubes anyway, because I'm mostly biking over ground that includes lots of thorns.
The first big surprise, is that only two wires come out of the motor wheel. It's a brush motor! No phases, no halls. I used a thumb throttle salvaged from I-can't-remember-where, I used 14 AWG silicon cable to run from the controller to the motor. I mounted an ammeter/voltmeter on the handlebars (as well as my PDA for navigation, a bell and a speedometer). I took off the front and rear mudguard. In a muddy field, the problem isn't mud getting on my nice clean (hah!) clothes, the problem is mud clogging up between the wheel and the mudguard and stopping the bike from even being pushed. The motor is nominally 24v, I'm running it on 8S Lipo (32 volts freshly charged, coming down to 26 volts empty). The rear carrier is great for panniers, which will hold whatever batteries I take on a circuit, plus water, a toolkit (I'll explain more about that later) and whatever else I need for a day out.
Today, I took it out for a test run. I got 25 kph on a slight uphill, 30 kph on a downhill. I get torque as soom as I give it some throttle, so it looks like a brushed motor isn't nearly as bad as I thought it might be. The controller is limiting the current to 10 amps, so the bike isn't very peppy, but I've ordered a 27 amp capable controller from Ebay (£9.99, brushed controllers are a lot cheaper than brushless).
I said I'd explain about the toolkit.
I like to carry enough tools to be able to fix most problems while I'm out, and the most obvious problem is a puncture. So I need two large spanners (front and rear), puncture repair kit, spare inner tube (lightweight), pump, bike lock, emergency front and rear lights and bike multitool. That means I need a bag about 12 inches long (to accomodate the pump and big spanners), 8 inches high and a few inches wide. I rummaged around my workshop, and found nothing suitable. Then I had a flash of inspiration, and I asked Ladysolly if she had any handbags she no longer used.
Ladysolly has more handbags than I would have thought possible, She has bags full of handbags, of every possible shape, colour and size, and all, of course, very expensive. My shoulder bag cost me £9.95, she laughs hysterically at such an absurd price and refuses to tell me what her handbags cost. It's a mystery, one of those female mysteries that I will never understand. So I asked her if she had any handbags that she no longer used, and no longer wanted to keep. Surely, I thought, some handbags must, from time to time, be discarded in favour of more fashionable and expensive hangbags? Apparently not. She needs them all.
So I was glumly rummaging through Ebay looking for a lady's handbag that wouldn't get me laughed at by passing motorists when I took it out to fix some problem, when she came back. Yes, actually, she has just the thing. It was given to her as a freebie when she was buying something else (lipstick, I think, probably with a pricetag that would turn my grey hair white). It has a designer label, and a £105 price tag. She's never used it, and never will, it being a very inferior specimen, apparently.
But it's just the right shape and size!
Here's a picture of it; a very nice leopard-skin bag
. You can see the "Jaeger" designer label, and on the left I've left the price tag on.
And here's a bird's eye view of the contents. Although I'm reliably informed that it isn't the contents that matters; all that matters is the designed label and the price tag
It's a 20 inch wheel folder, aluminium, with hub gears; an 8-gear Sturmey Archer gearbox. The nice thing about that sort of gear, is that you can change gear while stationary. I rode it for about a year, and then realised I wanted an electric bike. And when I got one, it went into the shed.
A few years (and a few bikes) later, I had a Synergie 20 inch wheel rear hub motor electric bike, which was very nice until the frame just broke apart while I was stationary (I hate to think what would have happened if I'd been zooming along in heavy traffic). I took the broken bike home, put it in the shed, and I've been using it occasionally for spare parts on my other Synergie, bike.4.
So I had just destroyed bike.4's motor wheel; expert opinion says that the internal gears have broken, and I don't think that this is fixable at any price lower than what a whole new hub motor would cost. Downer.
And then I got to thinking. I have that Downtube, which actually looks even prettier than the picture posted (suspension front but not rear), and I have the motor wheel from the frame-broken Synergie, what if ...
So I did. First I checked the front forks. The bike is aluminium, but the front forks are, hurrah, steel! And anyway, I put on two torque arms. So the project is feasible. The inner tube on the motor wheel had perished from age and disuse, but I prefer thick thorn-resistant inner tubes anyway, because I'm mostly biking over ground that includes lots of thorns.
The first big surprise, is that only two wires come out of the motor wheel. It's a brush motor! No phases, no halls. I used a thumb throttle salvaged from I-can't-remember-where, I used 14 AWG silicon cable to run from the controller to the motor. I mounted an ammeter/voltmeter on the handlebars (as well as my PDA for navigation, a bell and a speedometer). I took off the front and rear mudguard. In a muddy field, the problem isn't mud getting on my nice clean (hah!) clothes, the problem is mud clogging up between the wheel and the mudguard and stopping the bike from even being pushed. The motor is nominally 24v, I'm running it on 8S Lipo (32 volts freshly charged, coming down to 26 volts empty). The rear carrier is great for panniers, which will hold whatever batteries I take on a circuit, plus water, a toolkit (I'll explain more about that later) and whatever else I need for a day out.
Today, I took it out for a test run. I got 25 kph on a slight uphill, 30 kph on a downhill. I get torque as soom as I give it some throttle, so it looks like a brushed motor isn't nearly as bad as I thought it might be. The controller is limiting the current to 10 amps, so the bike isn't very peppy, but I've ordered a 27 amp capable controller from Ebay (£9.99, brushed controllers are a lot cheaper than brushless).
I said I'd explain about the toolkit.
I like to carry enough tools to be able to fix most problems while I'm out, and the most obvious problem is a puncture. So I need two large spanners (front and rear), puncture repair kit, spare inner tube (lightweight), pump, bike lock, emergency front and rear lights and bike multitool. That means I need a bag about 12 inches long (to accomodate the pump and big spanners), 8 inches high and a few inches wide. I rummaged around my workshop, and found nothing suitable. Then I had a flash of inspiration, and I asked Ladysolly if she had any handbags she no longer used.
Ladysolly has more handbags than I would have thought possible, She has bags full of handbags, of every possible shape, colour and size, and all, of course, very expensive. My shoulder bag cost me £9.95, she laughs hysterically at such an absurd price and refuses to tell me what her handbags cost. It's a mystery, one of those female mysteries that I will never understand. So I asked her if she had any handbags that she no longer used, and no longer wanted to keep. Surely, I thought, some handbags must, from time to time, be discarded in favour of more fashionable and expensive hangbags? Apparently not. She needs them all.
So I was glumly rummaging through Ebay looking for a lady's handbag that wouldn't get me laughed at by passing motorists when I took it out to fix some problem, when she came back. Yes, actually, she has just the thing. It was given to her as a freebie when she was buying something else (lipstick, I think, probably with a pricetag that would turn my grey hair white). It has a designer label, and a £105 price tag. She's never used it, and never will, it being a very inferior specimen, apparently.
But it's just the right shape and size!
Here's a picture of it; a very nice leopard-skin bag
And here's a bird's eye view of the contents. Although I'm reliably informed that it isn't the contents that matters; all that matters is the designed label and the price tag
