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Servicing Sturmey-Archer
4- 5- and 7- Speed Hubs

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by Sheldon "up high" Brown
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s5w.jpg

Cross-section of wide-ratio Sturmey-Archer five-speed drum-brake hub

General information

Sturmey-Archer has manufactured many 4- and 5-speed hub models over the years, and six 7-speed models. Another article on this site covers topics common to many Sturmey-Archer hubs. Please read that article to learn about

There are also articles on this site covering

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Gearing

Sturmey-Archer 4-, 5- and 7-speed hubs all are of a similar basic design using compound planetary gearing. They have two or three sun gears, and only one of them is locked to the axle at any time. The planet gears are stepped gears (two or three gears of different sizes, side by side, made of a single piece of metal so they all turn at the same rate). The large end of the planet gears engages the small sun gear, and the small end of the planet gears (middle section on the 7-speeds) engages another, larger sun gear and the gear ring. These hubs have a middle, direct drive ratio, and a choice of wider or narrower ranges depending on which sun gear is locked to the axle.

These hubs, or at least the older ones, have a "neutral" position when shifting the sun gears, because engaging two sun gears at a time would cause the hub to lock up. A sluggish or misadjusted shifter cable can allow the hub to freewheel or lurch forward. The older hubs also have a "neutral" between direct drive and high.

These hubs work best if the second-highest gear is the level-ground gear, around 70 gear inches (5.2 gain ratio, 5.5 meters development) The top gear is used for downhill and downwind riding. With a 7-speed. you might want to set the gear range a bit higher, as the steps between gears are smaller. If the terrain is all up and down, you might want to set the gear range lower. There is more detailed information on sprockets and on setting the gear range on another page.

Current and recent Sturmey-Archer 5-speed hubs

Sturmey-Archer has announced a new series of rotary-shifting 5-speed hubs as of late 2013; overall range 244%; ratios are:

Ratio .640 .800 1.000 1.250 1.563
Step 25.0% 25.0% 25.0% 25.0%  

Sturmey-Archer's previous 5-speed hubs, with model names ending in (W) for "wide", shift with a pullchain and have a wider range, as follows:

Ratio .625 .750 1.000 1.333 1.600
Step 20.0% 33.3% 33.3% 20.0%  

The steps between the three middle gears of these hubs are the same as for Sturmey-Archer three-speed hubs. The outer steps are narrower than the inner ones. That is desirable so that the step from the fourth gear to the top gear is not too large, but it reduces the step at the lower end of the range, not so desirable.

The table below includes links to technical information about these hubs, from the Sturmey-Archer Web site's listing of hubs, Sturmey-Archer catalogs, and a Web search. Rows in green are for hubs listed in the 2015 catalog. All of these have rotary shifting. Rows in white are for hubs no longer listed.

Model codes for hubs made in 1991 and later follow the pattern X-RD5, where R indicates rear, D a drum brake and 5 the number of gears.

Fittings, rotary-shifting hubs

Model Features Documentation
QS-RC5 Gearbox for tricycle. Has reverse gear, Claims rotary shifting but specs indicate pullchain, so, same as QS-RC5(W). Installation
QS-RC5 (W) Gearbox for tricycle. Has reverse gear, pullchain shifting. No technical information
RX-RC5 Coaster brake Installation
RX-RD5 Drum brake Installation
RX-RF5 Freewheeling, no brake Installation
RX-RK5 Disk brake fitting Installation
RXL-RD5 Large-diameter drum brake Installation
S5C(W) Coaster brake, steel shell Installation, parts list
S-RC5(W) Coaster brake, aluminum alloy shell Installation, parts list
S-RC5(W)(N) Coaster brake, aluminum alloy shell, 9-spline driver Like S-R5C(W)
S-RF5(W) Aluminum shell, freewheeling Installation
Parts list for drum-brake model
S-RF5(W)(N) Aluminum shell, freewheeling, 9-spline driver>

Installation
Parts list for drum-brake model

TS-RC5 Gearbox for tricycle. Claims rotary shifting but specs indicate pullchain, Coaster brake No parts list found
TS-RF5 Gearbox for tricycle. Claims rotary shifting but specs indicate pullchain. Freewheeling, no reverse gear. No parts list found
XL-RD5(W) Aluminum shell, 90 mm drum brake Installation, parts list, exploded drawing.
X-RC5(W) Aluminum shell, coaster brake, large flanges Installation, parts list
X-RD5(W) Aluminum shell, 70 mm drum brake

Installation, parts list

X-RF5(W) Large flanges, aluminum shell, freewheeling Installation
Parts list for drum-brake model
X-RK5(W) Large flanges, aluminum shell, disk-brake fitting

Installation
Parts list for drum-brake model

X-RK5(W)(N) Large flanges, aluminum shell, disk-brake fitting. 9-spline driver

Installation
Parts list for drum-brake model

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Design changes 1991-2009

Now we move back earlier in time -- 1991-2009 hubs had ratios as in the table below:

Ratio .667 .789 1.000 1.267 1.500
Step 18.4% 26.7% 26.7% 18.4%  

The 1991-2009 hubs were never very common, are no longer sold and can be tricky or impossible to repair, due to parts un-availability. But who knows, you might have a couple of these lying around so you can cannibalize and keep one going.

The first of these hubs were the "5-Star" (5-Speed Sturmey-Archer) hubs, introduced in 1991. The 5-Star hubs had cantilevered planet-gear axles, that is, the axles were only supported at one end, a Bad Idea. They were shifted by dual pullchains: the one on the right for high, middle and low, and the one on the left for a wider and narrower range.

"Sprinter" hubs, introduced in 1993, had single-cable control and a sturdier planet cage.

Later versions of these hubs, sometimes called the Summit series, included a patented "ball locking" mechanism for the sun gears. Some of these hubs continued to be made, or sold out of remaining inventory, until SunRace/Sturmey Archer rolled out a new wide-range series of 5-speed hubs in 2009. The ball-locking mechanism was reportedly unreliable in the 7-speed hubs: please see comments below, which probably also apply to the 5-speed hubs.

These hubs were supplied with an aluminum alloy shell, unless steel is indicated in the table below.

The hubs are listed in order of the year they were introduced.

Model Year Features Documentation
5 Star 1991 Two cables: unreliable, cantilevered pinion pins Technical information
Parts list
5 Star Elite w/drum brake 1991 Two cables: unreliable, cantilevered pinion pins Technical information
Parts list
Sprinter 1993 Single cable Technical information
Another source
Parts list
Sprinter Elite AT5 w/drum brake 1993 Single cable Parts list
Sprinter S5C coaster 1994 Single cable

Technical information
Parts list

SAB-5 Steelite w/drum brake 1998 Single cable Parts list
AB5, w/drum brake 1999 Single cable, ball locking, steel shell, 90mm brake. Still available after Taiwan move. Parts list
Summit S5 1999 Single cable, ball locking, freewheeling, steel shell, available after Taiwan move, reported on Tony Hadland's site Like X-RD5.
Summit S5C 1999? Single cable, ball locking, coaster brake, steel shell. Available after Taiwan move, reported on Tony Hadland's site No information found
Summit X-RC5 1999 Single cable, ball locking, coaster brake. Available after Taiwan move, reported on Tony Hadland's site No information found
Summit X-RD5 1999 Single cable, ball locking, drum brake. Technical information
Another source, also with specs
Summit X-RF5 1999 Single cable, ball locking, freewheeling, reported on Tony Hadland's site Like X-RD5.
Summit X-RK5 1999? Single cable, ball locking, freewheeling, disc brake fitting. I'm not sure this model ever actually existed. Like X-RD5.

 

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1945-1990

Now we go even deeper into the past. The FM medium-ratio four speed hub was introduced in 1939, and the FW wide-ratio four-speed hub, in 1945. It had all but the top gear shown in the table in the previous section. Additional four-speed hubs were added in the late 1940s. In 1967, Sturmey-Archer began making the S5 hub, which offered all 5 gears and was an easy upgrade from the FW.

This site now hosts Sutherland's Handbook of Coaster Brake and Internal Gear Hubs, with excellent rebuilding information on most of the hubs in this series. Boldfaced items in the table below are on this site. Other information linked below is mostly from the Sturmey-Archer Heritage site and Tony Hadland's Web site.

The hubs in the table below are listed in order of the year they were introduced.


Rebuilding information from Sutherland's Handbook
More information from Sheldon
Model Year Features Documentation
FM 1939 Close-ratio, rare Rebuilding information
Parts list
FW 1945 Four speeds, single cable Technical information
Rebuilding information
Parts list and exploded drawing with annotations
AF 1946 Same as the FC Rebuilding information
Parts list
FC 1946 Close-ratio, rare Rebuilding information
Parts list
FG 1946 Like the FW, with Dynohub generator Technical information
Parts list and exploded drawing
FB 1949 Like the FW, with drum brake Parts list and exploded drawing
S5 1966 Two cables, bellcrank on left Technical information
Another source
Parts list and exploded drawing
More information from Sheldon
S5.1 1977 Indicator spindle, pullchain both sides. Unreliable. Technical Information
Parts list and exploded drawing
More information from Sheldon
S5/2, S5/2A, 1983 Indicator spindle, pullchain both sides. Also sold with aluminum shell as 5-Speed Alloy. Technical information
Another source
Parts list and exploded drawing
More information from Sheldon
AT5 1985 Drum brake. Indicator spindle, pullchain both sides. Parts list
S5/2 II 1988 Axle modification. Indicator spindles changed. Technical information

About the FW and S5

The FW four-speed hub used the wide-range sun-gear setting to provide only a "super low" gear. The shift from normal "low" to "super low" ("2" to "1") required a very strong pull on the gear cable to overcome the spring that controlled the sun gears. This hub used a two-part indicator spindle whose adjustment is described here.

The right side of this hub was identical to that of the AW hub, and the internals would fit into an AW shell. The planet cage and axle assemblies were different.

Generator and drum-brake versions followed in 1946 and 1949. They used a narrower planet cage and plunger-type low-gear pawls, to make room for the generator or brake.

Many cyclists converted the FW four-speed into a five-speed by adding a separate shifter for the sun gears. This was a hot ticket for a club-riding bicycle, back around 1950.

Sturmey-Archer also made other four-speed hubs with narrower ratios, to appeal to club cyclists and racers. You may read more about them on Tony Hadland's site and the Sturmey-Archer Heritage site, and in John Allen's documentation of gear ratios. John Forester's writeup about these hubs is now on this site.

The S5 5-speed hub worked like the converted FW hubs. Most of the internal parts were the same as for the FW, and the right side including the gear ring remained the same as for the AW. The S5 used two cables:

The original 5-speed hubs used a bellcrank to push a rod inward to accomplish the sun-pinion shift.

IMG_7668bellcrank_pushrod.JPG

Best type of Sturmey-Archer bellcrank, with 2 7/16" stock pushrod

The S5 was sold with three different types of bellcrank, reminiscent of the story of the Three Little Pigs. One type of bellcrank was made partly of plastic and failed quickly. A second type used a flimsy steel stamping, and bent easily. Only the sturdy, forged type with internal threads is reliable, but it is rare. I've had some success modifying Shimano bellcranks to fit. I did this by re-threading them to fit the Sturmey-Archer axle. Taps for this purpose are not readily available, so I made a tap out of an old axle.

The bellcrank had to face forward to connect with the cable, and so it could not be tightened to secure the axle in the dropout. A separate axle nut was needed. The bellcrank works best with a 6 1/4" axle. Grinding a recess in the side of the axle to secure the Shimano bellcrank's grub screw and drilling out that bellcrank to fit over the threads also might work. A bellcrank could be fabricated from the flared axle nut used with a Sturmey-Archer indicator spindle. Wiith the bellcrank, the S5 was reliable and a fine choice for urban cycling. I [John Allen] still use an S5 hub, and you may be lucky enough to find one in an old wheel.]

5 3/4" and 6" axles also were sold, but they are not long enough when used with the good bellcrank if there is any spacing washer under the left-side locknut. The 6" axle is longer only on the right side. A pushrod for the good bellcrank can be made from a ten-penny nail by cutting it to 2 15/16" long (or 2 11/16" for the shorter axles) and grinding down its head to fit inside the bellcrank.

Unlike recent hubs -- andlike the AW -- all of the 4-speed and 5-speed hubs in this series could "walk" out of high gear position into the intermediate (neutral) gear during a hard sprint -- see comments by Jobst Brandt. The more common cause of gear engagement, though, was misadjustment of a shifter cable. With these hubs, there is a "neutral" gear between engagement of the sun gears as well as the one between middle and top ranges.

5-speed Controls

The weak point of the 2-cable 5-speed hubs was the shift control units. The S5 required a taut cable to prevent the primary sun gear from disengaging from the axle in first gear. Sturmey-Archer went through a number of top-tube mounted shift levers, which were never very satisfactory mechanically. The left-side cable needed to be very carefully adjusted, and the actual mechanics of the click stops in the two-lever controls were too weak, so they were quite unreliable, even though there was no real problem with the hubs.

Also, unsophisticated cyclists had trouble mastering the shift sequence of the two separate levers. It could also be confusing that the S5 must be pedaled forward at more than first-gear speed when shifting from second to first.

Later 2-cable versions reversed the spring loading on the sun gears, and used a conventional indicator spindle/chain to shift the sun pinions. The first of these, the S5/1, would not reliably stay in gear. The last version of the S5 hub, the S5/2 II, was also sold as the S5 Alloy and with a drum brake as the AT5. It was reliable, and it would shift into all gears without pedaling forward, but the problem with the shifters remained.

Sturmey-Archer eventually made a large and very complicated single-trigger control that would operate the two cables, but it was also very temperamental and required a lot of force to operate. The best control arrangement for a 2-cable 5-speed hub is a standard 3-speed trigger for the right cable, and a friction-type derailer shift lever for the left cable. The use of the friction shifter on the left gets around the problem of critical adjustment of the left cable, since you just pull it until it stops.

[I use a trigger on the left, in the 2nd and 3rd gear positions. Its latching in the 2nd gear position holds the cable taut. The cable does need adjusting occasionally. I have used the original S5, and the S5/2 II, each for years, and had no problems with them except when the cable is misadjusted -- John Allen.]

Newer 5-speeds (described earlier in this article) use a single cable, and rather different internals.

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7-speeds

In 1997, Sturmey-Archer introduced three models of "Sprinter 7" 7-speed hubs -- brakeless, or with a drum brake or coaster brake. These were the first production Sturmey-Archer hubs with rotary shifting. They are relatively rare. Ratios were as follows:

Ratio .600 .690 .804 1.000 1.243 1.450 1.667
Step 14.9% 16.6% 24.3% 24.3% 16.6% 14.9%  

Information below is from the Sturmey-Archer Heritage site and Tony Hadland's Web site.

7-speed hubs were also produced in the "Summit" series, with a ball locking mechanism for the sun gears, under different model numbers, in 1999 and 2000. These hubs did not remain in production after Sturmey-Archer's move to Taiwan.

These hubs were installed on some Moulton bicycles, and may have been reliable enough with the low-torque conditions of a small-wheel bicycle, but a cyclist who used them for heavier service in a hilly city reports:

The weak point of these hubs was the sun gears, and the system of fixing them to the axle. The original system used a sliding key, similar to that used in the Sachs/SRAM hubs, but one-sided (projecting from one side of the axle instead of both). This key and the notches that it engaged were prone to having their corners rounded off and then not yielding proper engagement. The next system used small ball bearings that would retract or protrude from the axle and engage the sun gears. Unfortunately, under extreme torque the sun gears tended to override the balls, either becoming permanently engaged with the axle or shattering. Back to the drawing board, eh?

Model Features Documentation
S7 Steel shell, no brake Technical information
Another source

Parts list
AT7/ Sprinter 7 Elite Aluminum shell, drum brake Technical information
Another source
Parts list
S7C Aluminum shell, coaster brake Technical information
Another source
Parts list
Summit S7 Aluminum shell, no brake, ball locking Like X-RD7
Summit S7C Aluminum shell, coaster brake, ball locking Like X-RD7
Summit X-RD7 Aluminum shell, drum brake, ball locking

Technical information

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Links

The Web sites linked below are very helpful for older hubs not covered on this site. The Sturmey-Archer Heritage Web site has a wealth of historical and technical information. Tony Hadland's Web site includes an exploded drawing and parts list for nearly every Sturmey-Archer hub ever made up through the 1980s, as well as rebuilding information for many older hubs. The service manuals include general information (such as how to replace pawls) not covered in the rebuilding information for individual hubs.

Rebuilding instruction for several hubs on Jane Thomas's site
Sturmey-Archer 1951 Service Manual on the Sturmey-Archer Heritage site.
Sturmey-Archer 1951 Service Manual on Vancouver Van Touring site
1956 service manual and 1902-2001 information on Tony Hadland's site

Sturmey-Archer logo
Official Site
old Sturmey-Archer logo Heritage site
Three-Speed Parts from Harris Cyclery
John Forester on five-speed hub gears
English Three Speeds, Care and Feeding
Internal-Gear Hubs
Sturmey-Archer Hubs, General Information
Sturmey-Archer 1902-1952
Sturmey-Archer 1935-38 Catalogues
Evolution of the Raleigh Sports
Sheldon's Moulton MKIII
Sheldon's Moulton MK3 with
S5 hub and hybrid gearing
John Allen's spreadsheets of internal-hub gear ratios
Martin Hanczyc's roadster pages.
Tony Hadland's Sturmey-Archer Pages
including the 1956 master catalogue and
a Web page with technical documentation on some of these hubs, among others.
Hubstripping web site
Retro Raleighs
SW Hubs by Brian Hayes
Jane Thomas's site with
Sturmey-Archer service manuals.
Menotomy Vintage Bicycles
Chat forum on English bikes.

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Articles by Sheldon Brown and Others


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Copyright © 1998, 2008 Sheldon Brown

Updated and revised May 29, 2010 by John Allen

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Last Updated: by John Allen