When it comes to 7 speed hub gears that are available in the current market, there are two approaches to implementation: First, the single stage approach, with compound planet gears having 3 different radii. This type of 7 speed implementation can be found in hubs produced by Sturmey Archer, and by Sachs, since the mid 1990’s.
Very briefly, they achieve 7 speeds by gearing up and gearing down through the same planetary gear set, ie increase gears are achieved by driving the planet cage (hub is driven by the ring gear) and reduction is achieved by driving the ring gear (planet cage drives the hub shell). 3 reduction gears (as the planet pinions have 3 steps) + 3 increase gears + direct drive = 7 speeds. Note that this design is kind of like an extension of the Sturmey Archer 5 speed: essentially an S5 with an extra sun pinion and with 3 stepped planet pinions instead of the two-stepped planets in the S5.
Option 2 is more interesting. Continue reading “Shimano Inter 7/Nexus 7 disassembly”
This particular hub was originally owned by Thorin (who I know vaguely through the MBTC). Thorin gave it to John Harland, but John wasn’t going to use it because he doesn’t like the uneven gear ratios (more on that to come later). The idea of pulling it apart came up at another swap meet, when I saw an 8 speed for sale, and suggested buying it. John told me about the old internals that he’d got from Thorin.
And that’s how this hub came to be donated to Science. Continue reading “Shimano Nexus 8: Stripped down & Reassembled”
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”
A close friend of mine, Glenn Rodda, has been using a Shimano Alfine 11 speed hub for a number of years (I’m not sure precisely when he first got one, but it was in 2010 or 2011). After his original hub started malfunctioning, he decided to buy a new hub and consequently the old one was donated to science. Which is how I was commissioned to pull it apart. Continue reading “Alfine 11 Strip Down”
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”
Many readers will be familiar with the Rohloff Speedhub, a 14 speed bicycle hub gear, and if you don’t know about it then you can go look it up on Google. Understanding how the mechanism works and pulling one apart have been a couple of my long term goals. This article won’t attempt to communicate the former (that is for a separate article I think) but I am going to tell you about how I pulled my hub apart and put it back together again (that is quite important too). You may want to go brush up on your knowledge of epicyclic gears right about now too, because I’m not doing any intro to that topic, it’s all assumed knowledge. Wikipedia has a very good article on the topic. Continue reading “Inside the Rohloff Speedhub”