Bicycle Mechanics - 3 speed troubles
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07-26-05, 03:06 PM
So I've got an old Sturmey Archer hub. 1st gear works alright. 3rd gear works alright. 2 gear slips like crazy. Any suggestions?
When I really crank on any of the gears, I skip links and there's some pretty awful crunching. Suggestions?
Strip it and check. Sounds like it's hosed. The 2nd gear slippage should be able to be cleared up by adjusting the indicator chain, assuming you didn't already do that.
Hmm.....the slippage happens to my wife and I often - usually a cable adjustment will take care of it though the adjustment is never as easy as I'd LIKE it to be!
The crunching however is worrisome to me - have you oiled it lately? The crunching suggests lack of lubrication to me, though it could certianly be something else.
More info would help - how old is the hub? Did it ever sit for long periods of disuse? The oils will eventually dry up with use and need to be replentished regularly, albeit sparsely. If the wheel stood in a stationary position for a long time the oils may have gunked up on one side of the hub.
For three speeds, I'd highly recommend Sheldon Brown/Harris cyclery's website: http://sheldonbrown.com/oldbikes/index.html
and see if you can find Glenn's New Complete Bicycle Manual http://www.amazon.com/exec/obidos/ASIN/0517543133/qid%3D949936242/sr%3D1-3/002-1729453-8355228 (c) 1973 & 1987 - or maybe at your local library? This books has lots of great info for old & clunker bikes and a nice troubleshooting section for various drivetrains & other systems, including the three speed and other planetary hubs.
07-27-05, 06:12 PM
slippage issue was fixed with chain adjustment. Thanks!
.....as for the chain "crunching" it's more a matter of the chain slipping on the teeth under heavy torque. Is the chainwheel worn out?
That will happen if the chain and rear sprocket is worn out. Check the chain length - 12 full links must be 12". If longer than 12" by about 1/8", then that may be the reason for the crunching. The front sprocket may be OK.
But 3 speeds may also slip like that internally if the ratchet or pawls in the hub are worn. Although if it happens in 2nd, then it must be the chain, 'cuz 2nd is directly driven.
If it slips and crunches in the middel position, couldn't that also be the innards messed up and not slipping out of low/high back to direct? I think My wife's Raleigh has crunched and munched on occasion too.
I have an Shimano 3 speed that will skip and jump in 2nd gear if it is not adjusted properly. On the Shimano the jumping is the hub shifting in between 2nd (1 to 1 ratio) and either 1st or 3rd gear. I have seen this on a S/A as well but not as pronounced as the Shimano.
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