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Sturmey-Archer 3 Speed Hub Gear Rebuild

Although not entirely indestructible, the Sturmey Archer AW has remarkable staying power. Careless changes tend to round the corners off the clutch (the part in a cross shape) and the accompanying lugs, but rarely does this stop the hub from engaging third gear securely. The clutch engages with the tops of the axles holding the planets (brilliantly). If these get very worn they can simply be substituted with others. Sloppy changes into first have no detrimental effect, merely pressing on the rear of the pawls whilst they might be under load. The most delicate part is probably the axle key; the small part with a hole in the centre that the toggle chain screws into. This can be bent. It's very simple to replace and you can find brand new parts on ebaY, or from Old Bike Trader. New pawl springs can be bought on ebaY or made from old electric guitar strings. If you use the second string, you get a sharper tick as it is a little stronger than the original.

Summing up the damage that you might find in an AW:

*worn clutch *worn high-gear pawls *worn or bent axle key *broken pawl springs *chipped planets (very rarely). If the mechanism has never been oiled, it may be rusty internally. Sometimes this will only result in the hub running slightly roughly.

Here is the rebuild sequesnce of the AW. Go slowly and carefully and you will have no trouble- I hope!

Grease the bearing track with lithium based grease.
Put bearing balls in, leaving a single space. Use balls from one source.
Put the ball ring cover on and tap carefully into place.
Grease the bearing track in the driver and put in a 1/4\" ball unit.
Put the ball ring cover on and tap carefully into place.
Repeat this operation on the left hand side of the hub shell.
Both hub bearings in place.
Hold the axle vertically in a vice with the end hole at the top and lower on the planet cage.
Planet cage in position on the axle.
Install a planet gear.
Install the axle with the smaller end upwards.
Repeat the previous two stages for the other three planets.
Put the clutch sleeve on with the flange lowest, like a top hat.
Install the clutch with the chamfered surfaces or square cutouts uppermost.
Push the axle key through the hole in the clutch sleeve, through the slot in the axle and out the other sleeve hole.
The flats on the axle key must be uppermost.
Install the thrust collar so that it locates with the axle key.
Install the thrust washer.
Take the annulus...
...and install it on the planets so that the gear teeth mesh.
Take one of the high gear pawls. Note the shape carefully and hold it in the way shown.
Hold one of the pawl springs on the pawl as shown...
...and carefully position it to line up the holes in the pawl and annulus, without letting the spring move
Take a pawl pin and install it on the annulus. The pin must go through the rouneded section of the spring.
Test the operation of the pawl. It should spring back positively. The pin should have the chamfered end down.
Install the ball ring.
Turn the ring to allow the pawls to be pressed back into place.
Locate the main spring and the spring collar on the axle. The collar is very important.
Pour in a couple of teaspoonsful of oil.
Hold the driver with the ball bearings just above the spring collar.
Screw on a cone so that it pushes the collar down, stopping it popping out through the ball bearing ring.
Screw the cone down to hand tightness, then back it off approximately half a turn. Screw the toggle chain in.
Pull the toggle chain to check that the gears work smoothly. Spin the hub by hand in each gear.
Turn the hub the other way up and tip another teaspoon of oil into the annulus.
Take a pawl and a pawl spring and hold the two together as shown.
Turn the pawl and spring the other way up and fit into place in the planet cage, locating the axle in the spring.
Take the pawl for the other side and locate the spring as before...
Install the pawl just like the other low gear pawl.
Coat the outside of the mechanism with oil.
Take the hub shell and pour a teaspoon of oil into it.
Install the complete gear mechanism in the shell. Rotate it to press the low gear pawls down to engage with the stepped track at the back of the hub shell.
Screw the gear mechanism into the shell as far as possible by hand.
Put the hub in the vice and screw on the left hand cone, but do not tighten it fully at this stage.
Position the anti-turn washer (flat sided internal hole).
Push the washer down on top of the cone.
Screw down the cone locknut by hand, again leaving it loose.
Put the hub in the vice after protecting the jaws with wood and tap the ball ring tight with an old screwdriver.
Align the right hand cone with the flats on the axle, using a Sturmey cone spanner.
The cone position is important. It should be no more than 3/4 turn out.
Install the cone locking washer.
Install the cone locknut and tighten with a spanner.
Turn the hub over and adjust the bearings with the Sturmey cone spanner and a 15mm spanner on the locknut. Tighten and check for play.
Turn the hub over again and install the dust shield.
Install the sprocket spacer ring.
Install the sprocket.
Put on the second spacer ring.
Ease the wire circlip over the driver and into the groove.
Screw in the gear chain and test the operation of the gears by pulling the chain and spinning the hub.
Put on the inner washer, the outer washer and flared nut. You will need to remove the adjuster barrel from the gear chain.
Put the washers on the left hand side and screw on the ordinary nut.
Grease the bearing track with lithium based grease.
start stop bwd fwd

The job's a good un!

Last Updated on Saturday, 13 August 2011 13:33