Saturday, July 20, 2013

Disassembly and Inspection of the 1953 Sturmey-Archer AW Hub

The next step in refurbishing the 1953 Raleigh Sports is cleaning and inspecting the front and rear hubs. The rear hub is a Sturmey-Archer three-speed AW hub with a date stamp of 53-10 (Oct. 1953), the front is a Sturmey-Archer GH6 Dynohub date stamped 9-53 (Sep. 1953).  This post will focus on the AW hub, a future post will cover the Dynohub.  The "A" series of hubs were introduced by Sturmey-Archer in 1936.  Initially there were three hubs in the series; "AR" close-ratio; "AM" medium-ratio; and "AW" wide-ratio.  By far the "AW" is the most common hub found on classic three speeds.  It has a "low" gear which was a 25% reduction from the middle or "normal' gear, and a "high" gear which is a 33 1/3% increase above "normal".

There are several online sources that provide diagrams of Sturmey-Archer (SA) internals and service instructions, I would recommend obtaining a copy for anyone attempting disassembly.  Tony Hadland the author of "The Sturmey-Archer Story" has a lot of good on-line hub information, Sheldon Brown's sites also contain plenty of information on SA hubs.

Before starting disassembly the exterior of the hub usually requires a good cleaning and degreasing.  Next record how the hub has been assembled on the axle, note the number and location of the cone locknuts, lock washers and spacers on both sides of the axle, a digital camera works great for this.  If the hub has a dished sprocket (reversible) note the orientation of the dish inward or outward.  This initial assemble is not necessarily correct or desirable.  Most of these hubs have had different sized spacers, nuts, washers etc. added or removed during its history and could be adversely affecting the chain line, dropout spacing, and wheel dishing.  (See previous post "Adjusting Chain Line on the Sturmey Archer AW Hub").

I'm not going to cover each disassembly step but will mention that one of the first steps, removal of the right hand Ball Ring can be one of the most difficult.  Some hubs come apart without much effort but there are others were this step can be frustrating depending on the amount of corrosion; a history of being used to stomp up hills; mounted in a wheel or not; an early model hub with square notches and wrench flats on the left hand Ball Cup; or later model with half-moon notches, and a pressed-in left hand Ball Cup without wrench flats.  Sometimes you get lucky, some not so much.

These are the AW internals after being removed from the hub shell.  The right hand Ball Ring can be seen with its square notches

A blurry picture of the Gear Ring and Planet Cage 

Another blurry picture of the right hand cone, bearings and driver

The Driver

Right hand Ball Ring, dust cover, and 24 loose 3/16" ball bearings

The Clutch in the bottom of Gear Ring and Gear Ring Pawls

An inspection of the 1953 hub showed rust corrosion and chips on some of the Pinion and Sun Pinion teeth.  Chipped faces on some of the pawls.  All cones and bearing races were deeply pitted.  The Ring Gear had severe rust corrosion on the faces of the inner teeth.  One nice thing about the AW hub is its interchangeability with other SA hubs and years.  In addition, most AW hub parts are still available on-line.  I was able to use some parts from a 1961 AW to replace the questionable 1953 hub parts.  Normally; I always replace the Clutch and Pawl springs.

This is the hub after rebuilding with new and replacement parts; re-lubrication; I use a special type grease instead of oil; buffing the hub shell and setting the proper chain line.  It is now ready for lacing into a new rim.  

Please share your thoughts and experiences.

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