Reports of the demise of this Web site are greatly exaggerated! We at sheldonbrown.com thank Harris Cyclery for its support over the years. Harris Cyclery has closed, but we keep going. Keep visiting the site for new and updated articles, and news about possible new affilations.
Servicing the Sturmey-Archer
AW
Wide-Ratio
Three-Speed Bicycle Hub
Note: these instructions apply to the classic AW hub manufactured up through sometime in the 1990s.
The new no-intermediate-gear version is very different.
Do not cut the spokes out of the wheel! You need the hub to be in a spoked wheel to turn the right-hand ball ring.
1. Unscrew everything from the left-hand end of the axle
If rebuilding a hub with a Dynohub generator, please read this to avoid weakening the magnet.
When gear and brake controls and electrical wires (if any) have been disconnected and the wheel removed from the cycle frame , dismantling of the hub begins with the removal of the left-hand locknut, the washers (if any) and the left-hand cone. A note should always be made of their order and number so that they may be put back correctly when the hub is re-assembled. In particular, different numbers of spacer washers may be fitted, depending on the spacing and chainline.
Left Axle Nut
HMN128
Axle Washer
HMW155 or HMW494
Locknut
HMN132
Spacer
HMW129
Cone
HSA101
The parts shown above are common to most models that do not incorporate a brake.
2. Unscrew the right-hand ball ring and internal assembly
Next, use a hammer and punch to unscrew the right-hand ball ring. Be careful not to snag a spoke with the punch, or you may damage it, or the hub shell.
As you withdraw the internal assembly, try to avoid touching the low-gear pawls while the unit is held sprocket-side up, because there is a risk of the pawl pins' falling out if you relieve the spring tension that holds them in place.
The right-hand ball ring has a two-start thread and must be replaced in its original position, that position must be marked. String or adhesive tape may be attached to the spoke nearest to the letters ' SA' which are stamped in one of the notches on the ring. The whole internal can now be withdrawn from the hub shell. (Installing the ball ring the other way may affect wheel true, but this is rarely a problem in practice.)
This is a standard right-hand thread, turn it counterclockwise to remove it.
3. Remove the low gear pawls, pins and springs.
The low-gear pawls are the ones farthest from the sprocket. The pawl pins are easily pushed out of the planet cage to release the pawls and springs. Watch out that the springs don't fly across the room and under the bed.
Low Gear Pawls
HSA111
Pawl Springs
HSA120
Pawl Pin
HSA112
4. Place the left-hand end of the axle in a vise
Then remove everything that is screwed onto the axle: the right hand locknut, spacer washers if any, cone lock washer and cone, making a note of their arrangement so that they can be replaced in their original positions.
Right Axle Nut
HMN129
Axle Washer
HMW155 or HMW494
Locknut
HMN132
Spacer
HMW129
Cone Lockwasher
HMW147
Cone
HSA101
5. Lift off in the following order:
The clutch spring and cap (cap not shown), the driver, the right-hand ball ring and the gear ring. There is no need to remove the sprocket from the driver unless you are going to replace it. Removing the sprocket is easier in any case when the hub is built into a wheel.
Clutch Spring
HSA128
Driver
HSA123
6. Remove the gear ring pawls, pins and springs.
The pawl pins are easily pushed out of the gear ring to release the pawls and springs.
Gear Ring Pawls
HSA119
Pawl Springs
HSA120
Pawl Pin
HSA112
7. Remove the thrust ring, and unscrew the indicator rod.
Thrust Ring
HSA283
Indicator Spindle
HSA125
Very old hubs had a two-part thrust ring. The old style thrust ring had the same inside diameter all the way through, with a separate thrust ring washer at the end where the clutch spring pressed on it (instead of the section of the part shown with the smaller inside diameter)..
8. Push out the axle key and remove the sliding clutch and sleeve.
Axle Key
HSA124
Clutch
HSA117
9. Lift off the planet cage complete.
10. Take out the pinion pins and remove the pinions from the planet cage.
Pinion Pins
HSA114
Planet Pinions
HSA115
If necessary, because of a worn bearing surface or ratchets, the left-hand ball cup may be removed from hub shell. If it has outside flat surfaces, it has a left hand thread and is removed by gripping these surfaces in a vise and turning the wheel in a clockwise direction.
More recent AW hubs have splined left-hand ball cups. These don't have wrench flats. To remove a splined left-hand ball cup, use a hammer and punch from the inside of the shell to knock it straight out. Use care to alternate sides from blow to blow so that the ball cup comes out straight, not crooked.
The channel-section dust cap in the left-hand ball cup, like that in the driver is a press-in fit and may be prised out with-a wide screwdriver to avoid damage. If a new ball retainer and balls have to be fitted it is recommended that a new dust cap is fitted at the same time.
Ball Retainer
HSA284
Outer Dust Cap
HSA102
Reassembly
1. Left-hand Ball Cup
If the left-hand ball cup has been removed from the hub shell, replace it by screwing anti-clockwise (it has a left-hand thread).
A newer splined left-hand ball cup may be pressed in with an inertial impact alignment instrument (hammer) using care to keep it straight, not crooked. It is a good idea to use a wooden block to spread the force.
2. Prepare the following preliminary sub-assemblies:
If rebuilding a hub with a drum brake, please read this so you put the brake back together correctly.
Fit the ball cage into the left-hand ball cup, with the ring of the ball retainer facing outwards and the recess in the dust cap also facing outwards. If a new ball retainer is being fitted, the dust cap also should be new.
Fit the ball cage into the driver, with the ring of the ball retainer facing outwards and the recess in the dust cap also facing outwards. If a new ball retainer is being fitted, the dust cap also should be new. If the sprocket has been removed, see no. 21 below
Fit the balls (only 24, 3/16" diameter) and the inner dust cap to the right-hand ball ring, making sure that the balls can revolve freely with the dust cap in place.
Fit the pawls, pins, and springs into the gear ring as described in the general instructions to 'The Re-assembling of Sturmey Archer hubs. (The planet-cage pawls, pins and springs are not fitted at this stage.)
Smear grease in the channels of the dust caps of the left-hand ball cup and the driver and in the recess of the right-hand ball ring. Do not use grease anywhere else. Water-resistant boat-trailer grease is best: see additional information.
Hold the left-hand end of the axle in a vise, so that the slot for the axle key is above the sun pinion, and fit the planet cage.
Add the planet pinions and pins. (The small ends of the pins protrude.)
Fit the sleeve (flange first), the sliding clutch with recess on the flange of the sleeve, and the axle key (with the flat of the key facing upwards), and screw in the indicator rod to hold them in that position.
Fit the thrust ring and washer, making sure that the flatted ends of the key engage properly in the slots of the thrust ring.
Fit the previously prepared gear-ring sub-assembly.
Fit the previously prepared right-hand ball-ring sub-assembly.
Fit the previously prepared driver sub-assembly.
Drop the clutch spring over the axle
Fit the cap (optional -- not really needed) and screw up the right-hand cone finger tight. Then loosen it back half a turn and lock it in that position with the special washer and locknut. On no account must the cone be unscrewed more than half a turn, as that would throw the gear mechanism out of adjustment.
Remove the assembled mechanism from the vise and, while holding it with the planet cage uppermost, pour about two teaspoonfuls of a good quality thin oil into the cage.
Hold the cycle wheel in the left hand, with the open (right-hand) end of the hub shell facing downwards, and insert the assembled mechanism from below, screwing-up the right-hand ball ring finger tight only.
Make sure that the position marks made on the ball ring and the hub flange before dismantling will register properly, and then screw up tightly.
If the sprocket has been removed from the driver, fit the outer dust cap over the driver before replacing the sprocket, and see that the dust cap is properly centered on the flange of the driver. Replace the sprocket and spacing washers in the arrangement noted when dismantling, and add the circlip.
Reports of the demise of this Web site are greatly exaggerated! We at sheldonbrown.com thank Harris Cyclery for its support over the years. Harris Cyclery has closed, but we keep going. Keep visiting the site for new and updated articles, and news about possible new affilations.