Internal Gear Hub maintenance help

Hi,

trying to help friends fix their rubbish student bikes which all have internal epicyclic gear hubs... never dealt with these.

The recurring problem with these hubs seems to be the gear slipping off causing the whole system to free wheel without the chain turning the wheel. It happens when changing gear and can be rectified by shifting the gear a bit - but it makes the bikes pretty unridable.

Everyone seems to have these problems with the old bangers they've been sold... and the LBS are repeatedly charging £££s for fixing...

Anyone know how to fix these?

Thanks a lot
Ben

It's almost always poor adjustment.
Search for Sturmey archer to find previous threads with more detailed info, but basically assuming all the cable stops are firmly fixed and not moving then adjust the cable tension so that in 3rd the cable is just about under tension and you should find 1st and 2nd are spot on.

Sturmey 3 speeds are built like tanks and hardly ever go wrong. Just add a bit of oil every so often and keep them adjusted and they are perfect for decades.

https://www.lfgss.com/thread19623.html

Here is more detail

Out of interest is it sturmey or sachs or shimano?

with a sturmey, there should be a hole in the end of the axle, and you adjust the tension of the cable so that the end of the rod (attached to the end of the chain) pokes out by a couple of millimetres. this probably doesn't make sense, but if you look up the way internal gear hubs work then it should become clear that the 'freewheeling' effect is simply down to poor adjustment.

sorry i can't be more clear, but it should be a simple fix.

thanks so much, i'll have a look and get back to you with results. cheers

Neutral is between middle and top.
If it spins in middle, the cable is too loose.
If it spins in top, the cable is too taught.

If you end up being totally stuck, you can bypass neutral by loosening the cable until you get top gear when the lever is in top, and middle gear when the lever is in bottom (you would get neutral when the lever is in middle). You lose the bottom gear, but two gears is better than none.

Also, fresh oil helps - use SAE30. Lubricating the cable and shifter will prevent the cable from sticking (which causes spinning when you try to change from middle to top).

AW hubs are really stunningly good for everyday pootling. I don't know why I sold mine.

yeah they're sturney and thanks that's really useful... thanks guys

Hi Domini.

I'm happy to help if you need to fix up any old Sturmey's or give you a crash course one weekend. I've stripped and serviced loads and have a full Sturmey parts box and spares.

The slip on the old AM hubs is often caused by the pawl springs clogging with oil grease and years of neglect. Good news is they are dead easy to fix with a good clean up. Don't be scared of opening them up for a play.

PM if you need a hand.

Although AWs are famed for their longevity, worn hubs tend to have a bigger inbetween gear IME, and can be almost impossible to get adjusted correctly. That said, sticky or worn cables and shifters can also cause problems. Check cable condition and routing, and lubricate well. New shifters are cheap.

Fortunatefool, don't you mean AW not AM hubs :)

I'll second/third/fourth the above. The 3 speed AW is ubiquitous, cheap, plenty of spares are available and you only need very basic tools to open one up and service them. Built very solidly and very low maintenance.

Ive got an odd one.
its 1950s and a generator hub. no model number on it though!

it has an oil port but when i cracked it open was running on a very weighty grease (which was knackered and drying out), assumed these all ran on oil so put half a pint of sa30 (lawnmower oil) in there which promptly ran out all over the floor from both sides.
guess it was a grease hub after all? but running grease in there the frehub us rubbish and shifting either way is very slow and clumsy.

anyone any ideas?

http://sheldonbrown.com/sturmey-archer/ag.html

Strip it down.
Wipe the grease off with a rag.
Clean it out completely with paraffin.
Rebuild and add about 2 or 3 teaspoon of sae30. (not half a pint lol)

Do not separate the armature and magnet.

^ thats instructions for an ag hub which sounds similar to yours, but take photos, notes etc of the order of parts as you strip down. Be very careful not to lose pawl springs.

Ive got an odd one.
its 1950s and a generator hub. no model number on it though!

it has an oil port but when i cracked it open was running on a very weighty grease (which was knackered and drying out), assumed these all ran on oil so put half a pint of sa30 (lawnmower oil) in there which promptly ran out all over the floor from both sides.
guess it was a grease hub after all? but running grease in there the frehub us rubbish and shifting either way is very slow and clumsy.

anyone any ideas?

If it's Sturmey it should run in oil. but you only want a little bit, not half a pint.
Most hubs I have stripped down were working badly because someone had packed them with grease. Once cleaned and given a few drops of oil all their problems went away

maybe you just put too much in?

Old sturmeys run on oil but aren't sealed, so do best with regular small doses. You know you are feeding them too much when your rim gets oily!

Do not separate the armature and magnet.

+1
http://www.lfgss.com/post511278-24.html

2-3 spoon fulls you say?!!!
Diditwrong lol

2-3 spoon fulls you say?!!!
Diditwrong lol

Yeah certainly no harm done. Its part of their enduring design that when they are working right you add a few drops of oil each month and any excess drains off and helps flush out any crud.

when your rim gets oily!

I lolled.

Cheers for the info guys.

Amazingly I had no idea how much should go in there, so I took the view it should be at least 60% full (i.e. to ensure it reachs all the parts all the time), hence half a pint made it in there! Which then immediately escaped, probably leaving about 5 spoon fulls in the bottom.

I guess the tip of the gear in there just flicks that tiny bit of oil around and keep it running clean?

Last question...... can the wheel be trusted to be on its side, i.e. when travelling in a car etc? Or will those spoonfuls just end up all over my car?

Yeah its gonna seep out dont risk it.
Placing it on a decent amount of rag should be enough protection.

Sweet cheers!

When I opened it up, really didn't appear to be a lot of wear on the gears like I expected, I did find a decent amount of pitting though. Only real thing of note was the lack of a decent freewheel! if you take feet off pedals it becomes a whirlwind of shin pain lol.

Slightly off-topic, but this seems like the best place to put it: I have a wheel with a 4 speed nexus hub in it, I'd like to get a trigger shifter that works with it (you can't buy the originals I don't think, but I'd be happy to be proven wrong). Presumably the only important thing is cable pull - i suppose it is too much to hope that a sturmey archer trigger would work? eg this 3 / 4 speed one from ebay?

1) Maybe jtek or someone could make a travel adaptor so the cable shift was right, but to do that I'd need to know the cable pull for both a sturmey archer 4 speed lever and my nexus hub....
2) maybe one of the newer SA thumb shifters would work, but again, i don't know the cable pulls.