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Wednesday, 16 November 2011

Servicing a Sturmey Archer AW hub

The Sturmey Archer AW hub is 75 years old this year. The reliability of this design means that there are plenty of these hubs still in service. The ease of serviceability of this design means that returning one of these hubs to its former glory isn't all that difficult. Many minor issues such as resistance to freewheeling, hub seizure, general resistance to rolling and problems accessing certain gears can be fixed by taking the hub apart, cleaning the internals and re-assembling it all with some fresh grease.

Whilst I have written about working on an AW hub previously, the nature of the work means that it is difficult to take pictures whilst cleaning and re-assembling the hub. Thankfully, this time I was able to get a little help with taking pictures. To open up an AW hub (and most other Sturmey Archer hub gears) remove the left-hand (non-drive side) locknut and cone and uncrew the right-hand ball ring using a hammer and a flat screwdriver on the semi-circular cut outs of the ball ring (these are not rounded on the older versions of the AW). This should let you get the internals out, axle and all. This can be further disassembled by removing the right-hand locknut and cone, which allows the rest of the hub mechanism to be taken apart.

One of the notches for unscrewing the right-hand ball ring

Left to right: The left-hand axle nut, non-turn washer, locknut, spacer and cone

Left to right (top): right axle nuts (later integrated into a single piece), non-turn washer, locknut, cone lockwasher & cone. Middle: cone. Bottom: indicator rod (with indicator rod locknut seen above the locknut)

Left to right (top): Dust cap, sprocket snap-ring. Bottom: spacers. Assembled as: Dust cap, spacer, sprocket, spacer, snap-ring.

The driver assembly and clutch spring

Gear ring (left) and right-hand ball ring (right)

Left to right: clutch sleeve, clutch, axle key and thrust ring

Top: Axle (including sun pinion). Bottom (left-to right): Planet-cage, 4 planet pinions (cogs) and 4 pinion pins.

The low-gear pawls in the planet-cage can also be removed if necessary, although when removing these be sure not to lose the tiny pawl springs in the process. The same also goes for the pawls in the gear ring.

Once all this has been disassembled, a good cleaning with some degreaser and a cloth or paper towel should restore the hub to its former glory. Particularly dirty or rusty parts can be soaked overnight or cleaned with wire wool (just make sure to remove any left-over bits of wire wool before re-assembling the hub).

To re-assemble the gear mechanism, hold the axle vertically with the drive-side pointing up (axle hole above the sun pinion).

Add the planet pinions and the pinion pins back into the planet cage and place the assembly over the top of the axle with the planets at the top.

Add a dab of Sturmey Archer hub gear grease to the planet pinions and rotate the planet cage assembly around the axle a few times to distribute the grease around.

Place the clutch sleeve over the axle and line up the hole in the sleeve with the hole in the axle.

Place the clutch over the axle and the clutch sleeve.

Slide the axle key through the hole in the clutch sleeve and axle, with the threaded hole in the axle key lined up with the centre of the axle.

Slide the thrust ring over the axle key and clutch, lining up the grooves in the thrust ring with the protruding parts of the axle key.

Place the gear ring over the planet cage assembly and clutch assembly, being sure to line up the grooves inside the gear ring with the planet pinions.

Place the right-hand ball ring over the gear ring.

Add some lithium grease to the ball bearings within the ball ring (ideally more neatly than this).

Place the clutch spring over the axle, ensuring the plastic (or metal) ringed-end of the spring pointing upwards.

Place the driver over the axle. The clutch spring will push against the driver until the right-hand cone is added to hold the driver in place.

Add lithium grease the the ball bearings in the driver assembly and screw the right-hand cone onto the axle as with any other cup-and-cone bearing system.

Add the cone lockwasher and locknut.

Add lithium grease to the left-hand bearings.

Add the left-hand cone, spacer and locknut.

On the right-hand side, add the dust-cap, a spacer, sprocket, another spacer and snap ring to the end of the driver assembly.

The wheel may be bolted back into the frame, the indicator rod screwed back into the axle key and to the gear cable and the hub is ready to be tested. With any luck, the hub should perform just fine for another couple of decades. The 'no intermediate gear' (NIG) versions of the hub, such as the current AW hub, the S-RF3 and the gear mechanism in the X-RD3 are fairly similar to this, with minor changes to the clutch assembly and the driver, which has its own pawls in this version. There have also been numerous small revisions throughout the run of the original AW hub, although they should pose little trouble when using this guide as reference. The best advice I can give anyone who wishes to service one of these hubs is to just go for it; when disassembled the hub really isn't as daunting as it may appear from reading this guide (or similar guides).


  1. Thanks for this post, it is so clearly documented and photographed I'm inspired to start stripping one of my hubs! One question though, as the hub that most needs some attention is a Dynohub, I was wondering if you had any experience you could share relating to the risk of demagnetising the hub?

  2. Nice post Chris - can see this page sending your hitcounter into overdrive :>D

    Me reckons you have those technical photos licked - the job is truly a good one. (Now how do we turn an AW3 into a 3SX?)

  3. @Nick Salt,

    Sheldon Brown's website has some instructions for dismantling the front Sturmey Dynohub. Having seen both of these hubs up close, it seems almost certain that the innards of the dynamo mechanism are identical, with the AWG also squeezing in a 3 speed gear mechanism too. The instructions suggest that the dynamo mechanism can be removed as a single piece without demagnetisation being an issue. After that, the rest should be the same as the AW.


    I think this'll be a slow burner, few will read this on the off chance they may want to service a hub in the future, but Google may lead them to it in the future if their hub is in need of some attention.

  4. Great job, Chris -- I found your photos really useful in my first attempt at fixing a broken AW. One note to other novice mechanics like me: when you're putting the guts back into the hub shell, it's probably best to hold the hub horizontally (i.e., the way it fits on a bike) -- if you try to drop the internals into the hub shell vertically, the left-hand pawl pins can fall out and make a run for freedom.

  5. thank you,excellent pictures,clearly written.I'm taking mine apart tommorrow!

  6. @BG,

    You are correct, the low gear pawl pins don't always fall out if they have a bit of grim holding them in place, but on a cleaner hub they would've fallen out if held in the same manner as I did in the pictures.


    I hope it went well.

    1. It went very well ,thank you.I bought one that i thought was trash to practice on for 5 bucks,you couldnt even tell what it really was!Now I have a rebuilt 54'S/A too!


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