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Sturmey Archer Hub Gears

Sturmey-Archer Title

Sturmey-Archer; it has a real ring to it doesn't it? Trips off the tongue as delightfully as Lennon-McCartney or Laurel and Hardy. The trouble is that if there was any justice in the world the world's favourite hub gear would be called "Reilly". William Reilly invented a very successful 2 speed hub gear at the turn of the 20th century. He designed the 3 speed hub gear soon after, but was prevented from patenting it in his own name by the conditions of his contract. Instead, his friend James Archer supplied his name. A syndicate was formed to make the invention and well-known bicycle journalist Henry Sturmey added his own name, simply as a marketing move. Reilly was subsequently sidelined, left the company and was erased from history. That is, until Tony Hadland did some thorough research for his book The Sturmey-Archer Story, published in 1987.

Tony's book is well worth buying if you have any interest in British engineering, and mechanisms in particular. Not only is the story a fascinating one, full of drama and told with effortless precision, but the huge number of high quality drawings are evocative of the bygone era. The Sturmey-Archer Story is an excellent reference text, thoroughly absorbing and practically speaking, very useful; Hadland's masterpiece.

The AW 3 Speed Hub

Sturmey AW Leaflet

Sturmey-Archer made one of the World's favourite hub gears, fitted to millions and millions of bicycles. It was called the AW, and will almost certainly be the hub that you will encounter on a restoration project. Raleigh fitted it to almost every hub-geared machine that they ever made, including the Chopper, the Wayfarer, the 20, the Moultons Major and Minx and the Grifter. Raleigh owned Sturmey-Archer and the two factories were juxtaposed. They made over a million AW three speeds in 1964 alone.

The AW's gears are usually changed by a trigger, the middle gear being direct drive. You might encounter a twistgrip changer on 1960's machines like the RSW, or a gear lever on the Chopper. Much earlier bikes had a frame-mounted Chopper-type lever, only in very small scale, to be moved by a thumb. This design came before the handlebar trigger that we know so well. Triggers started off as metal alone, but in the late 1970's they acquired a bulbous black plastic end on the lever, a safety measure probably called for by the Americans. Well, it was analogous to the MGB's rubber bumpers.

Sturmey AW Leaflet

These days, it is so easy and cheap to get hold of an AW hub, i.e. from ebaY or down at your local Household Waste Recycling Centre, that there is no reason not to have a go at stripping or rebuilding one. Even if you did make an error, or simply lost the plot in the middle, it wouldn't matter; it is nothing valuable. You should regard rebuilding a hub as a kind of enjoyable mechanical puzzle for which there are clear instructions and photographs. And really, the AW is not bafflingly complex.

Sturmey AW Internals

Here are the internals of an AW 3 speed hub gear. Thanks to Wikipedia Commons for the excellent photo.

The FW 4 Speed Hub

Sturmey FW Poster

FW stands for "Four Speed Wide Ratio", the ratio meaning the size of the step between one gear and the next. Overall, the gear range of the four speed was almost identical to the AW wide ratio three speed hub described above. However, because there were four steps, the gears were closer together. Dr. Moulton was a fan of the FW, fitting it to the Moulton Deluxe for several years (the Standard had a 3 speed). The FW should have been the "Hub of the Future", but unfortunately it's future, as a four speed at least, ended in 1968.

Interestingly, as will be described in more detail in the page "How hub gears work", the four speed is actually capable of producing an extra high gear. Sturmey Archer was concerned about the second lever that would be necessary to operate this "overdrive" and withheld the introduction of the five speed hub for decades. When it was finally introduced to the market in 1966 it had an awkward-looking bell crank on the left hand nut. This was very soon improved by a change to the familiar toggle chain. It seems likely that the 5 speed ushered in the departure of the FW. Why have four gears when you can have five? This came a little too late for Dr. Moulton though, and to my knowledge Raleigh themselves do not appear to have fitted the 5 speed hub to any bike other than the Chopper Sprint.

Converted 4 speed

At one time you could still buy the axle assembly to turn an FW into a 5 speed (called an S5). There was essentially only one differently shaped part. My brother sent off for this axle in the early 1990's and received one of the last ones. This gear passed to me and I currently use it on a Moulton Mini. You will have to look closely, but the bell-crank was no longer available and a gear cable is now used to push the overdrive selector rod down the middle of the axle. This was a clever solution pioneered by the bicycle engineer Jack Lauterwasser, who worked for Moulton. It is a great shame that the Moulton Super 4, which had the FW, did not become the Super 5 after 1968. It is difficult to get higher gears on a small wheeled bike and the extra top gear of the S5 is a useful bonus.

Sturmey Four TriggerIf you are looking for a bicycle to restore on ebaY or at a Household Waste Recycling Centre, always be mindful that there may be a four speed hub fitted, and it should be saved. The sort of bike that will have one, apart from an old Moulton, will be a diamond frame big wheeler, for example a black Raleigh with a fully-enclosed chaincase, the type a policeman in an Ealing comedy would ride. Or a Rudge with an odd red/purple paintjob; a quality bicycle. Check the gear trigger for a large "4" in place of the "3" that you usually see. And don't think that they are too rare to be found.

Sturmey-Archer FW Leaflet

Sturmey-Archer FW Leaflet

Medium Ratio Sturmey Archer Hub Gears

Alloy Sturmey AM HubThe first place you should look on any old bike that that might be saved from the scrap skip is the rear hub. Why? Firstly because it will have the date stamped on the shell, the month and last two letters of the year. Unless the wheel is a replacement, this date will correspond closely to the year the rest of the bike was made.

Secondly,if you are really lucky, you might find that instead of the usual chromed steel, the hub shell is made from a duller material, aluminium alloy. And if so, you will see that the model code is not AW or FW, it might be AM or FM. These two codes stand for Three Speed Medium Ratio and Four Speed Medium Ratio respectively.

They are both brilliant hubs, the three having big, tough planetary gears and the four being one of the most advanced designs that Sturmey-Archer made until the 1970's.

The bike shown below was found by my brother abandoned on the street in Newcastle-upon-Tyne. He thought the wing nuts looked unusual and rubbed the oil off the hub to discover an AM underneath. Other clues that something unusual might be fitted were the dropped handlebars, stainless steel spokes, slender front forks and seat stays and relatively lightweight (although still steel) chainset.  This was a Raleigh Ladies Sports model made in 1950 to a high standard. The colour of the frame is very evocative of 1950's pastel shades and in fact is a classic Cycle Club colour. This would have been top of the range at the time it was in the shop window and an expensive machine. 

Ladies Raleigh Sports

So, why have gears closer together in sports bikes? The reason is, if you are riding closer to your physical limits, you don't want to experience a big jump in gear when changing either up or down. Although the overall range is narrower, one supposes that racing cyclists stick to flatter routes.

Interestingly, in the FM, the top three gears are all fairly close together like the AM, but the bottom gear is much lower. In fact, the 1st gears of the FM and the FW are the same; a drop of 33% down from 2nd. It's like a racing hub for Scouts; be prepared with an emergency low.

Last Updated on Sunday, 07 November 2010 22:42