This story begins at another Vintage Club swap meet. John Harland had brought along a lot of stuff to sell (he went there with more than 100 kg loaded on his bike, and didn’t want to take it all back home), which included two Sturmey Archer 3 speed hub gear + coaster brake jobs.
Fun fact, this all happened back in April, and it’s taken til now for me to get my shit together to write this up. Working full time, you see…
I already have more hub gears than I have bicycles to put them in, so I wasn’t all that enthusiastic about taking them. However, I noticed that one of the hubs was seized up, so I decided it could be interesting to pull it apart just to see what was wrong, and to attempt to restore it to working order. But mainly just to see how it works, since I don’t have any use for either of these hubs, and (being completely satisfied with cantilever brakes) no motivation to use a coaster brake hub. Continue reading “Strip down: Sturmey Archer S3C”
Recently, I acquired a four speed Sturmey Archer hub. I was feeling a bit bored the other day, so I pulled it apart, and had a look at the bits.
Normally, taking apart these hubs requires a lot of effort, since the force of the pedals tightens the screw threads, but this time it was easy. Quite obviously someone else had pulled it apart before me, even the bearing lock nuts were only finger tight.
Here are some pictures of the internals:
I didn’t take any pictures of the bits of the internals, too busy focusing on what I was doing. Note the compound planet pinions: the way this system works is that there are two ranges depending on which sun gear is locked to the axle, a really wide three speed and a not so wide three speed. You can get 5 gears from this mechanism (middle gear of both ranges is direct drive, which is the same regardless of sun gear selection).
The four speed hub doesn’t use all of the available gears. Highest gear is the high gear of the not-so-wide range. Changing down from second to first (lowest) gear, the sun pinions are slid along the axle to engage the low gear of the really wide range.
In order to convert this hub to a five speed, we will modify the shift mechanism so that we can move the sun pinions independently of the main clutch. That way, we will be able to select the high gear in the really wide range; the only gear not available to the four speed hubs.
Yesterday the Vintage Bike Club had their swap meet at Abbotsford Cycles (an event that happens about twice a year). There were lots of old bike bits, and I happened across a Sturmey-Archer FW (four speed, wide ratio) hub.
It so happens that I now have quite a collection of Sturmey-Archer products. There is one AW 3-speed that I used to use for riding around town, another 3-speed-plus-dynohub which is unbelievably heavy and finally, two front dynohubs (one of those is missing an axle however, which as you can imagine is slightly problematic). Continue reading “Swap Meet: New Acquisition”