Bicycle Mechanics - stripped hub??
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12-28-04, 08:57 AM
Good morning folks; I ran into some problems this AM on the commute. As I started to pedal my cranks turned, chain moved my rear cassette but the wheel did nothing. I'm thinking I "stripped" the rear hub. It would catch and I could pedal but it would slip often. On a second note it was really cold...16F. Perhaps the hub was wearing out and due to the cold the metal contracted just enough for the hub to slip. Do I need a new hub? new wheel ? It's an old late 80's cromo Specialize Stumpjumper. New bike? It is a beater. Thanks Charlie
More likely the grease hardened in the cold and kept the freehub pawls from springing into place. I'll bet when the hub warms up it works fine.
What you need is a lighter weight lube in the freehub.
12-28-04, 09:31 AM
Really!! Thanks. She's warming up now, so I'll take her for a nooner and see what will happen. Charlie
12-28-04, 09:32 AM
You may have some moisture in the freehub that froze up, keeping the pawls from engaging correctly. Bring the wheel inside for a while and see if it works ok after it's warmed up a bit. Relubing to try to displace the moisture may be in order.
12-28-04, 07:02 PM
Well it worked well after it warmed up all day. But I have recently had some problems with a slipping feeling from the rear cassette/wheel. I tried adjusting the cable, chain is fairly new, rear cassette 'seems' decent. I'm starting to think this problem may also be associated with my hub. All of the problems started as the weather got cold. I'll grease the hub and see what happens. Thanks for all your help. I may have a few greasing the hub Q's soon. Charlie
12-28-04, 07:24 PM
Check the part tools website, they have a pretty good explanation there on the task with pictures
12-28-04, 09:14 PM
The grease is probbably gelling from age too, so definitely repack it.
Balto: you better use oil rather than grease for the winter. Try an experiment: put the lube you propose
to use in the freezer, or leave it out overnite if in the low teens F and compare the viscosity when
cold with room temp. The pawls in the freewheel/freehub have relatively weak springs and if the
lube stiffens up, the pawls stick resulting in your problem. This might be a situation for thin oil
(but check the response to cold, to be sure there is no waxy stuff precipitating out). If you go
with oil just relube more often to replace runout, then go back to less viscous stuff next spring.
You generally don't need to repack a freewheel or freehub. they usually are very difficult to disassemble and reassemble. All that usually needs done is to drip oil (motor oil usually works fine) in the gap between the fixed and rotating parts. Drip in the oil until you hear the ratchet sounds get muffled from the oil.
If motor oil gets too thick in your neck of the woods this time of year, then try a lighter lubricant. chain lube might work if it's a 'wet' type, but even then, many chain lubes have a volatile solvent desined to carry a thicker oil deep into the chain then evaporate leaving the thick oil behind. In extreme temps, maybe a 5 or 10 weight motor oil or even something like 3 in 1 oil will work. A freewheel/freehub does not need much lubrication as it bears no load when spinning.
12-29-04, 05:49 PM
thats true, freewheels are a ***** of a job to reassemble. Ive done it and i lost a bunch of ball bearings :(. unfun
12-30-04, 12:17 AM
You do want to be sparing with the non-grease lubes if it can get near the axle bearings, as in a cassette freehub. If it contacts the grease it will have a thinning effect.
Conversely, I usually assemble the ratchets with a light grease and then run just enough oil into them to make the pawls work propperly. It seems to hold up better than pure oil and runs nicer than plain grease.
Yes, rebuilding them is a royal pain. Most of the ones I've done were around 48 mini balls, bleck. :(
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