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Sturmey Archer

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Ransomes MG 2 no 141 at Stoke Goldington 09 - IMG 9722
A Ransomes MG tractor fitted with a Sturmey Archer engine.
BulldozerD11Added by BulldozerD11

Sturmey-Archer are a manufacturing company originally from Nottingham, England. They primarily produce bicycle hub gears but have also produced motorcycle hubs, gearboxes and air cooled Engines.

HistoryEdit

The company was founded in 1902 by Henry Sturmey and James Archer under the guidance of Frank Bowden, the principle owner of the Raleigh Bicycle Company.[1]

A big chunk of company history missing here (nearly 100 years !! )

In 2000, the assets and trademarks of Sturmey-Archer were sold to SunRace Sturmey-Archer Inc. and operations were moved to Taiwan, with European operations in Amsterdam.

ProductsEdit

Gear hubsEdit

Sturmey-Archer's most widely-known product is the AW 3-speed gear hub, introduced in 1936 and still in production as of 2008. It is the survivor of a much larger range of "A" model 3-speed hubs, including the AM (medium ratio for "club" riders), the AC and AR (very close ratio for time triallists) and the ASC (a unique 3-speed fixed gear). In 1939 a 4-speed model FW was released. This led to the development of a series of 5-speed models, and by 1994, 7-speed hubs were introduced. Production was low, and in the mid-2000s these were discontinued. The XRF8, XRD8, XRR8, and XRK8 8-speed hubs entered series production in 2007.[2] SunRace Sturmey Archer have improved the design and manufacture in many respects; compared to the old AW hub, the current 3-speed equivalent (SRF3) now has an aluminium alloy shell for lighter weight, and reduced spoke breakage due to aluminium being softer allowing the spoke to seat into the flange and disperse the stress at the bend in the spoke over a wider area.[3] [4] The new hub also eliminates the no-drive position found on most AW hubs between normal and top gear.

All these hubs use epicyclic (planetary) geartrains of varying complexity. The AW is the simplest, using one set of planetary gears with four planets. The AM uses three compound planets with differently-sized cogs on a common shaft to engage the gear ring and sun gear separately, while the close-ratio 3-speeds, and hubs with 4 or more speeds, use multiple planetary geartrains. Depending on the specific hub these may be in series with each other, or with one or the other set being selectable at any given time by locking a particular sun gear to the axle.

DynohubEdit

The Dynohub was Sturmey-Archer's hub dynamo for bicycles. The Dynohub was designed as a means of generating electrical lighting power for bicycles during World War II. The initial GH12 12-volt model was introduced in 1936. This was followed several years later by the GH8. This 8-volt unit was in turn supplanted in the 1950s by the lighter-weight GH6 6-volt version, which remained in production through the early 1980s. The term "dynohub" is sometimes applied generically to bicycle hub dynamos, but it originates as a trademark.

The GH6 version produced a rated output of 6V, 2W from a 20 pole ring magnet with a stator having a continuous winding. Original headlamp bulbs are 6V 0.25A (1.5W) (e.g., CRY5) and a rear bulb of 6v 0.04A (0.24W) (e.g., CRY8). Common substitutions are a 2.4W headlamp bulb and a tail lamp bulb of 0.6W. This is different from a modern standard bicycle dynamo, though replacements can still be had.[5] One rider reports much more light with a 6.3V 0.25A (1.6W) type 40 bulb.[6]

Rated output was reached at around 20 km/h (12mph), a rotational speed of approximately 60rpm. The name dynamo implies DC output, but as usual with bicycle dynamos (known as generators in North America), output was in fact alternating current.

Dynohubs were offered as front hubs and as rear geared hubs. The AG was an AW 3-speed rear hub with inbuilt dynamo, while the FG was a dynamo similarly combined with an FW 4-speed.

Hub generators were absent from Sturmey-Archer's product range from the 1980s until the 2006 introduction of the X-FDD front hub, which combines a 6v, 2.4w or 3w dynamo with a 70mm drum brake.[7]

Engines & GearboxesEdit

The Sturmey-Archer name was also credited with the 49cc two-stroke engine fitted to early Raleigh mopeds, although this was actually a reworking of Vincenti Piatti's "Trojan Mini-Motor" and built by BSA's motorcycle operation.[8]

The company also produced small 600 cc air-cooled engines for a period that were used in the Ransomes, Sims & Jefferies small Crawler tractor built from the mid 1930s for market gardens and orchards called the Ransomes MG tractor.

Cultural significance Edit

Port Meadow's level green grew near
With Wytham Woods and Cumnor Hurst
I clicked my Sturmey-Archer gear
And pedalled till I nearly burst -
And, king of speed, attained the lead
And got to gushing Godstow first.

Excerpt from Summoned by Bells
by John Betjeman, Poet Laureate.

In the UK "Sturmey Archer" is a genericized trademark that is occasionally used to refer to any kind of hub gear, regardless of manufacturer. Talk of Sturmey Archer gears can also be nostalgic, referring to the days when hub gears were more common.

The John Shuttleworth song Crich Tram Museum reminisces about his boyhood activities and recalls cycling up a tall hill, singing "I was grateful for the Sturmey Archer gears"[9].

Half Man Half Biscuit refer to the gears in their song A Lilac Harry Quinn.[10]

See alsoEdit

ReferencesEdit

Based on the wikipedia article

  1. Sturmey Archer Heritage website
  2. Sturmey-Archer gear hubs
  3. Schraner, Gerd (1999). The Art of Wheelbuilding. Buonpane Publications, 31. ISBN 0-9649835-3-2. 
  4. Brandt, Jobst (1893). The Bicycle Wheel. Menlo Park, CA, USA: Avocet, 63. ISBN 0-9607236-2-5. 
  5. Commercial cycle bulb supplier
  6. GH6 Dynohub Head Lamp and Tail Lamp Bulbs
  7. Historical Hub Archive. Retrieved on 2007-10-24.
  8. Raleigh Moped history
  9. Crich Tram Museum by John Shuttleworth
  10. "McIntyre, Treadmore and Davitt".

External linksEdit





Smallwikipedialogo This page uses some content from Wikipedia. The original article was at Sturmey Archer. The list of authors can be seen in the page history. As with Tractor & Construction Plant Wiki, the text of Wikipedia is available under the Creative Commons by Attribution License and/or GNU Free Documentation License. Please check page history for when the original article was copied to Wikia

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