Tag: Gears

Sturmey Archer S3X Fixed Gear 3 Speed Hub

Sunrace Sturmey Archer have published details of a new fixed-gear 3-speed hub, which is currently at the prototype stage.

The details are as follows:

  • Overall gear range is 160%.
  • Direct drive is 3rd gear, with reductions of 25% and 37.5%. This translates as gear steps of 20% and 33%.
  • This The hub will feature a "much stronger aluminium hubshell".
  • No details are given about shifters, but a "bar-end style shifter" looks a possibility.

The new S3X is a new interpretation of the Sturmey Archer ASC hub, which was a Fixed Gear 3-speed hub produced from 1946 to the late 1950s.

The S3X has a wider ratio than the ASC, which had an overall ratio of 133% (-25%, -10%, Direct).

Some links for information on the ASC hub:


The Sturmey Archer ASC 3-Speed Fixed-Gear Hub, from Sturmey Archer Heritage

The full Sunrace Sturmey Archer blog post is below.

Tuesday, September 2, 2008
S3X Fixed Gear 3 Speed
So I know there are many of you out there that are very interested in the little bit of info I recently got my paws on.

The first batch of prototype Fixed Gear 3 speeds is finished. The new hub will be called the S3X. The hub will be made using a much stronger aluminum hubshell. Overall gear range will be 160%.

* 1st Gear -37.5%

* 2nd Gear - -25%

* 3rd Gear - Direct Drive

* Gear step gear 1 to gear 2: 20%

* Gear step gear two to gear 3: 33%

Shifters are still up in the air but we have had many requests for a bar end style shifter. Also we are still planning on the possibility of doing some anodized colors with laser etching instead of screen printed graphics. Please comment on what you would like to see in the way of shifters or color choices.

New "Silent" Hubs from Shimano

From VeloVision Online...
Alfine and Nexus 8 hubs get 'smooth' roller clutches instead of pawls...

Shimano have announced a change to their 8-speed internal gear hubs. Previously, like most such hub gears, they used a freewheel-like system of pawls to ensure one-way rotation of various internal parts:

This does of course create a clicking sound...

Now they've moved to roller clutches which are near-silent in operation:

These also offer, they say, quicker engagement, which should make shifting a little faster. This final image shows how the new hub internals use three of the roller clutches:

The 'smooth' hubs have new part numbers:
- for roller brake SG-8R31 (std), SG-8R36 (premium)
- with coaster brake SG-8C31 (std), SG-8C36 (premium)
- Alfine (for disk brake): SG-S501

Overtaking Boris

Was it a Moulton that overtook Boris Johnson on an evening in February 2006?

The other night a woman overtook me on her bike on the climb up to Islington. Nothing unusual about that, except that her wheels were only the size of soup plates. How was it possible that the revolutions of her tiny wheels could cover the ground more quickly than my huge wheels, when as far as I could see our feet were pumping up and down at the same sort of rate. I gazed at her retreating form with the baffled awe of a tribesman seeing his first aeroplane. Was it an optical illusion? Was it the gears? Not for the first time, I wished I understood physics properly. Is it true that a clock loses weight as the spring unwinds? Does a boat really go more quickly through cold water than hot water? The worrying thing is that the nation of Newton and Faraday is becoming almost as ignorant as me. Over the past ten years the number of students taking A-level physics has fallen from 45,000 to 30,000, and the number of university physics departments has fallen by a third. It is madness, not least since physics graduates are the best paid of all.

One week after the article was published in the Spectator, the letters to the editor contained the following:

Sir: I was surprised to read that Boris Johnson, as a cyclist and historian, had not pondered on what had allowed the reduction of wheel size from the ordinary 'penny-farthing' with the crank drive to that of the conventional bicycle which he no doubt rides (Diary, 11 February). It is, of course, the chain drive with the larger chainwheel at the crank and a smaller sprocket at the hub which enables the revolution of the cranks to be independent of wheel size. The Starley 'Safety' incorporated this. Lord Hailsham was probably the first parliamentarian to enjoy the benefits of the yet further reduction of wheel size with the Moulton bicycle.

He acquired this in 1964.

The letter was signed Alex Moulton.

New 8-speed Sturmey Archer Hub Gears

Sturmey Archer (or Sunrace Sturmey Archer as they are officially known these days) are at the International Bike Show in Taipei, and they're showing off a new 8 speed hub gear with a wider 325% range. This compares favourably with the 305% range on the current 8-speed. Pictured below is the disk brake version (X-RK 8), but it is expected to be available in the roller, drum and freewheel (no brake) versions also.

They are also bringing back a coaster brake version of the 5-speed hub gear. I'm a big fan of coaster brakes so I'm very happy to hear this. Currently, if you want a Sturmey hub with a coaster brake, you have to settle for a 3 speed.

A few new products that we are debuting at the show are the all new 8 speed hub as well as bringing the 5 speed coaster back into production. Both models offer a wider gear ratio with many internal changes.

All new 8 speed. 325% total range.

New 8 speed, disc side.

Closeup, new 8 speed.

Duomatic Anti-Rotation Washers

I recently got hold of some new anti-rotation washers for my Fichtel&Sachs Duomatic hub.

The washers do exactly what they say on the tin... they resist the tendency of the rear axle to rotate under the heavy braking torque.

I found these difficult to source, mainly becuase they are rarely listed in English. They are however listed in the SRAM spare parts catalogue (6Mb PDF).

There are two versions. One version features a pair of lugs that sit in the dropout slot to assist in resisting any rotation. The other type is plain, flat without any extension, with a serrated surface to increase the friction between the washer and the rear dropout.

The SRAM spare parts numbers are :

65 0517 110 10 - Retention washer with extension (Fixierscheibe mit Haltenase, if your googling or ebaying)

65 0517 102 000 - Retention washer without extension (Fixierscheibe ohne Haltenase)

Both are listed on several German bike sites, for less than €1, but the postage costs were extortionate, so I found them on eBay (and ordered with the help of Babelfish translation) at a slightly higher price but with a fair charge for postage and packaging.

I should point out that these washers are for the earlier models with the 10.5mm axle, not the later model with the 9.5mm round axle.