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20" Wheel Commuter

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A couple of years ago I needed a new commuter and I was sick of deraiIleur gears, so I decided to go with an On-One frame and Shimano 8 speed nexus hub. The monkey thought the new hub might work, it was very new and exciting and they thought giving it to me would be a useful test before they started putting them into courier bikes. The hub is actually quite nice as cheap hubs go. It's fairly light, there's a good range of gears and it has a hub brake option. Unfortunately it won't shift under power and it's a little fussy about shifting in general, as the indexing is in the shifter so leaning a little on the grip-shift pushes it partly out of gear and it makes really ugly clunking grinding sounds. Don't do that! But is it Moz- rated? The brief answer is: no.

Broadly, I'm a fairly strong rider (800W+ peak power) and I ride fairly hard. So the first hub lasted about 5000km, of which the last 1000km featured interesting grinding noises. Finally it got to the point where it wouldn't freewheel at all, and in fact I could ride backwards. Oddly it would still shift, and the amount of resistance to freewheeling changed slightly between gears. Shimano gave me another one under warranty (a new innards, so I didn't have to rebuild the wheel). I decided to try to be more gentle with the new one, no trailer towing and attack the hills less enthusiastically.

Which was a nice theory, and I managed the no-trailer part pretty well. But hills? Not so much. So the second one also lasted 5000km, and failed just before the two year Shimano warranty on the first hub ran out. But did I get a replacement from Shimano? No. Luckily the Monkey stepped up and gave me a replacement on them, so that was cause for much gratitude. I toyed with the idea of buying a second Rohloff to put in it, but Dave couldn't come up with a way to put the Rohloff plus disk brake into the On-One frame. So I will be putting the new Rohloff into the quad instead.

This leaves me with a dodgy 26" wheel mountain bike that probably has about 5000km left in it if I keep riding it. At the same time, I've seen some posts to the framebuilders list about commuting/touring bikes with 20" wheels, and since my first Rohloff is in a 20" wheel, that seems like a good option. So I asked on the list and got a link to this camping bike that looks pretty reasonable. The dismantling option might be useful, as that would let me sell my Birdy too. The Birdy is nice but $1000 for a bike I use about 200km a year? Hmm.

20" commuter bike sketch

So I sketched up some plans like the one above to get rough sizes and see if the shape worked for me. The frame and with my mountain bike behind it and please excuse my really poor mannequin. The MTB and person are pretty accurately sized for me, I traced those off photos a few years ago and base most of my designs on them now.

The big pain here is the rear pannier. I need about 380mm between the BB axis and the front of the pannier, which pushes it way out past the rear axle. with a 26" wheel that's not really an issue because the wheel sticks out so far anyway. But with a small wheel it gets a bit silly. I'm tempted to extend the wheelbase of the bike 100mm or so to make it work better which will also give a slightly more stable feel. But then it won't pack as small. But I think I'll just wear that, it's going to pack into a suitcase even if it's 100mm bigger than Drew's bike in each dimension.

I've also sketched a front rack that will also take that pannier, because after BinBike I'm enamored of front racks that are part of the frame. I think a bolt-on rail that mounts to two points at the top might be enough, but if I need to add a bottom mount point I can do that too.

So far all I have are these plans. And a desire to buy a TIG welder and start playing. But if it works Phuong also wants one, since she is tiny and has a kids MTB (24" wheels) that weighs a ton. We shall see :)