Before the Nexus and Alfine internal hub geras, Shimano hub gears were not regarded as well as those made by Sturmey Archer. Shimano’s answer to the AW hub was the 333 hub. The hub was generally less well liked than its main rival due to the fact is was not able to match its extreme durability. Because of their lower durability, there are fewer of these hubs around nowadays and spares are much less widely available for this hub.
A few weeks ago I purchased a Universal folding bike which was built on the other side of the iron curtain many years ago. It came with a 333 hub and a seized gear cable. Like the modern Nexus INTER-3 hubs, the 333 hub shifts via a bell-crank mechanism which transforms cable pull into a pushing action on a rod which sits inside the axle, changing the gears. Unlike the modern Nexus 3 speed hub (but in common with the AW), when cable tension is relieved, the hub defaults to 3rd gear. The seized cable terminated in a barrel adjuster, much like the one found on a Sturmey AW gear cable. Unlike the AW hub, the cables are no longer widely available and the barrel is of a different diameter.
The 333 shifter contains a ball bearing on the underside of the lever plate. This ball bearing is what holds the cable in place, at each gear position, and it will fall out when you disassemble the shifter.
The underside of the lever plate, with the ball bearing sat in its socket
Fortunately, at the shifter end the cable terminates in a cylinder which runs perpendicular to the cable, and it is of similar dimensions to the one used with the modern plastic Sturmey Archer gear shifters.
The lower portion of the trigger shifter housing, with the lever plate installed and the cable being fed in
The cylinder at the end of the cable sits in the hole in the lever plate, and a white plastic piece sits on top of the cable and lever plate. The cable is then pulled tight to allow the top part of the shifter housing to be re-attached.
The re-assembled shifter
At the other end, the barrel adjuster from the old cable was cut off and attached to the end of the new Sturmey Archer cable using a cable pinch bolt from a caliper brake:
Old cable meets new cable via a cable pinch bolt
The barrel adjuster was then used to align the gears up with the shifter:
The bell crank showing gears 1,2 & 3 from top to bottom. I believe the circular hole to the left of the hinge pin on the bell crank is supposed to allow a mark on the moving piece to be seen when in second gear, but has corroded away on this hub.
Hopefully this work-around will help other people out there trying to salvage an old 333 hub. Despite their reputation, having taken the bike out for a spin the gears seemed perfectly acceptable, smooth shifting and similar in range to the AW.
When we lived in Cambridge I had a bike with one of these hubs.
ReplyDeleteI was planning a trip to somewhere or other by train when I rode past a skip containing a folding bike much like yours.
Apart from fitting new tyres, chain and brake blocks, I did no work at all on this occasionally used bike in ten years. I had no trouble at all from the old Shimano hub.
We gave the bike away before we moved, but probably should have kept it. Despite the lowly reputation of these bikes, I found it rode quite well.
@David,
ReplyDeleteI think the quality of the 333 improved throughout its fun, but the damage to its reputation was already done by then and stuck, probably unfairly. The bike is with its new owner now, which is probably for the best as I was starting to get a bit attached. He seemed happy with it, and I'll be able to see how well it holds up as the years go by.
You'll be convincing people to use derailleurs with too many articles on the innards of hub gears.
ReplyDelete@pete,
ReplyDeleteI think there is a benefit to knowing less about hub gears, most of what I have read about them makes them sound terribly complicated when in fact they are quite simple, and reliable enough so that the average person would not need to concern themselves with their workings
Thanks for the info and the pictures.
ReplyDeleteFWIW, on the 333 hub that I am currently cleaning up, the mark on the moving piece of the bell crank that indicates second gear (an "N" in a circle) is stamped on both the top and the bottom of the piece. So if the top one has corroded away, you might try turning the bike upside down or using a mirror to see if the bottom mark is visible.