Talk:Derailleur/Archive 1

Invention decade?
Are you sure that derailleurs were perfected by the 1930's? I did a bit of googling on the issue and it seems that Tour de France riders weren't using them until after WWII, and even in the 1950's the gear systems were very primitive compared with modern derailleurs. --Robert Merkel 00:38 Mar 27, 2003 (UTC)

Derailleur gears were banned from 1919 until 1937. In some way it offered an unfair advantage to riders but this needs clarification - whether it was due to riders being tied to specific companies such as Simplex (France) Vittoria and Campagnolo (Italy) is unclear. However by 1937 the only gear allowed in the TdF was the "Super Campion Gear" (or Osgear - named after the company owned by top cyclist Oscar Egg) and the Vittoria Margherita - both with chainstay mounted paddles and single, lever mounted chain tensioner coming from the chainset end. *http://www.classiclightweights.co.uk/designs/osgear-hs.html--Mook3 (talk) 14:58, 4 April 2008 (UTC)

These derailleurs with chainset-biased mechanisms are interesting insomuch that they were lighter, simpler, and less likely to 'clog' than the cluster biased parallelogram variety.

Fausto Coppi famous for his multiple Tour, Giro and classic wins, switched from the Simplex Parallelogram version that was becoming increasingly popular. 'Persuaded' to switch from Simplex to Campagnolo he won the !950 edition of Parix Roubaix using the short lived 'Cambio Corsa'. This incorporated a bizarre mechanism that kept chain tension via ratcheted quick release rear hubs that moved the wheel backwards or forwards along the horizontal dropout, with a remote rod operated mechanism on the seat stay. *http://www.theracingbicycle.com/Tullio.html Mook3 (talk) 14:37, 3 April 2008 (UTC)

This is where I found my information *http://www.exploratorium.edu/cycling/gears1.html It could be wrong of course, although Its possible that derailleur gears were reasonably well developed by the 1930s, but usage didn't become cheap/widespread until the 1950s. I think the fact that Tour de France riders didn't use them until the 1950s might be because many riders looked down upon multi-geared bicycles and viewed them as an unnecesary mechanical complication. G-Man 18:32 27/3/2003 UTC

How could Degrange make his quip in 1902 if the derailleur wasn't invented until 1905? One of these dates must be wrong. Lisiate 09:16, 13 Aug 2003 (UTC)

Good point. The derailleur as we know it today wasn't really invented until after WW II, but Degrange made his famous quip in 1902 because:
 * The 1905 derailleur was not the first - various other derailleurs existed back before the turn of the century, and
 * Companies like Sturmey-Archer (founded 1902) were making variable gtear systems based on Internal hub gears (instead of derailleurs) AHands 12:20, 13 Aug 2003 (UTC)

I believe the Campagnolo Gran Sport was the first modern parallelogram dual jockey wheel derailleur in 1951. There were derailleurs before, but not with the combination of dual jockey wheels and parallelogram. Older derailleurs used various mechanisms to derail hte chain, sometimes slider mechanisms with a jockey wheel, sometimes paddles that weren't in contact except durin shifting, parallelogram not being necessary to be a derailleur. If I rememeber, I'll do a bit more research and polish something to clarify. --Pqdave 17:37, 1 Dec 2004 (UTC)

The subsequent section I started Talk:Derailleur_gears meanders a bit, but I eventually sorted out some history, and there's a few citations there. Basically, racers adopted derailleurs later than tourists, for various reasons.--SportWagon 22:54, 18 August 2006 (UTC)

Meaning of "Derailleur"
What does "Derailleur" mean? Is it named after an inventor, or is it a (for example) French language word? &mdash; Matt Crypto 17:51, 14 May 2006 (UTC)

From the article "When a rider operates the lever, the changes in cable tension move the derailleur from side to side, "derailing" the chain onto different gears." So they're named after how they operate. Lisiate 20:52, 14 May 2006 (UTC)


 * And yes, it is a French language word. Sheldon Brown has an explanation here: http://www.sheldonbrown.com/derailer.html (along with arguing for the anglicisation of the word.) -- Blorg 15:33, 14 July 2006 (UTC)

Really Early Campagnolo
Someone who has owned a succession of bike shops in Toronto owns, or at least once owned, a Legnano bicycle with a Camapagnolo three-speed derailleur system of sorts. I think it dates from the late forties or early fifties.

There were no jockey wheels--the rear dropouts were instead unusually long, and the wheel itself moved to adjust the chain slackness. To change gears you loosened the rear axle using an underseat lever which was connected to the rear-wheel quick-release. You then arranged to make the wheel move forwards or backwards in the dropouts--a rack-and-pinion mechanism maintained side-to-side alignment of the wheel. (Perhaps you actually cranked something to cause the movement; I'm not sure about that detail). You had a derailleur of sorts; little more than a spade attached to a separate lever under the seat. You used that to persuade the chain to move to the appropriate one of the three sprockets available. From memory (as is this whole recollection) the sprockets were all relatively large, and did not vary more than six, possibly only four, teeth from smallest to largest. (I'd guess 17-20-23). After everything was positioned properly for your new gear, you tightened up the remote-control quick-release and could once again ride with full pressure.

I should try and track down more Internet documentation of this, or perhaps contact the person I mention.--SportWagon 19:11, 9 August 2006 (UTC)


 * These derailleurs were the Cambio Corsa or later Paris-Roubaix derailleurs. http://www.campyonly.com/history.html --SportWagon 19:19, 9 August 2006 (UTC)


 * So, I am suggesting that "Some early designs used a system of rods to move the chain onto various gears." be expanded with more details. Did Campagnolo have competitors?  Was the parallelogram design with jockey wheels delayed by regulations which effectively prohibited jockey wheels in competition?  Etc.--SportWagon 19:23, 9 August 2006 (UTC)


 * John Forester's history of the derailleur http://probicycle.com/jf/jfderail.html - seems that Campagnolo had "something" to get introduced into top-level racing, even though others, principally Simplex, had workable reasonably modern (compared to the Cambio Corsa and Paris-Roubaix) designs much earlier.--SportWagon 19:39, 9 August 2006 (UTC)


 * Reading of Forester above suggests (Simplex) derailleurs were allowed in the Tour de France in 1938, but still did not become the norm then. It didn't seem to be until the scary Cambio Corsa and similar short-lived Paris-Roubaix derailleurs, soon followed by the (now) "conventional" Gran Sport, that derailleurs really caught on in such top-level competition.  Note that a two-speed "flippable" hub with no jockey wheels allowed at least one of the gears to be a "fixed wheel" (no freewheel)--an advantage up hills.--SportWagon 19:51, 9 August 2006 (UTC)


 * History of derailleur (racing) http://www.theracingbicycle.com/Tullio.html - more balanced than Campag-oriented reference above, suggests, e.g. Coppi did use Simplex derailleurs in 1947 Tour de France.--SportWagon 20:05, 9 August 2006 (UTC)


 * Perhaps a more detailed description of Cambio Corsa and Paris-Roubaix would fit into Multi-speed versus single-speed (possibly renaming that section--Jockey wheels or no jockey-wheels, perhaps?). One can surmise (but evidence should be found) that Campagnolo was trying to get the advantages of both single gear and derailleur with his systems.  --SportWagon 20:10, 9 August 2006 (UTC)


 * Surveying the web a bit, the problem is people (myself included) see the Cambio Corsa system, and think "that looks primitive", and assume therefore it predates essentially modern rear derailleur systems, whereas in fact it did not. After some overcoming of tradition and bigotry, the modern derailleur took over.  Well, perhaps increases in robustness made it more suitable for racing.  (Tourists could stop to clean or oil, but racers couldn't).--SportWagon 20:17, 9 August 2006 (UTC)


 * here is an illustration of that Campy jockeyless derailleur, circa 1946. That website has quite a lot of interesting historical bike-stuff. If you snoop around a bit, you'll see Huret direct-parallelogram derailleurs of 1948. And here is a bunch of scans from old Peugeout catalogs, showing bikes with parallelogram derailleurs as early as 1935. adamrice 21:21, 14 August 2006 (UTC)


 * http://www.m-gineering.nl/oldtech.htm (from Derailleur gears External Links) contains, among other things, a picture of a Paris-Roubaix derailleur on a bicycle equipped with four rear sprockets.--SportWagon 18:40, 15 August 2006 (UTC)

All Campy?

 * for several decades true racing bicycles were all Campy,

A quick search suggests, but doesn't fully confirm, that French firms such as Mercier ridden by Jacques Anquetil would use Simplex equipment in the Tour de France.--SportWagon 19:56, 9 August 2006 (UTC)
 * Quote for several decades true racing bicycles were all Campy, meaning that drivetrain groupset &mdash; the derailleurs, shifters, hub, cassette and chain &mdash; were all manufactured by the Campagnolo company.
 * Clearly not true. Simplex, Huret, Galli, Mavic, Gipiemme, Zeus, Suntour have all made derailleurs, and it's only recently that Campagnolo made chains, or had chains made with its name. LDHan 19:13, 14 August 2006 (UTC)

Merge Jockey Wheel into here
Because Jockey wheel is so short, I have copied the current version here for easy reference.


 * Jockey wheel - The upper of two pulleys housed in the lower cage of the rear derailleur (or rear mech) of a bicycle. (The lower one is called the "tension pulley.") The derailer pulleys are usually constructed of plastic, and often have teeth that makes them look a bit like sprockets. The cage which houses the pulleys is hinged at the main body of the derailer, and its purpose is to take up the slack on the chain. The cage is sprung to force it clockwise, as viewed from the right, thus keeping tension on the chain through the range of gears.


 * Modern derailer pulleys usually consist of a plastic cog, two metal dust caps, a central bushing of steel or brass and the fixing screw (which also holds the two sides of the derailer cage together). The jockey pulley has a tendency to work themselves loose, so the fixing bolt should be tighened securely, and the threads lubricated with grease or coated in a thread-locking compound to prevent this happening.

IMHO, this article (Derailleur gears) contains ample information about jockey wheels (contradicting Jockey wheel in at least one detail, however). However, the Jockey wheel article goes on to give detailed mechanical description and maintenance tips which I would think not appropriate for the Derailleur gears article. Would it be appropriate to include those tips here, or would it be appropriate to merely say those tips are not really within the scope of Wikipedia? If neither of those is an option, the Jockey wheel article should continue to exist. (Note also idiosyncratic spelling "derailer").--SportWagon 21:10, 9 August 2006 (UTC)


 * I now see the References for this article (Derailleur gears) contain
 * Bicycle Repair in Wikibooks
 * That, combined with the lack of repair tips in this article, suggests to me that repair tips are not appropriate in Wikipedia--SportWagon 21:25, 9 August 2006 (UTC)


 * Yes, merge it. Not every sub-component of a bike needs its own article, and if the jockey-wheel article stands, I will be forced to start articles on the headset crown race, water-bottle boss, etc. adamrice 21:04, 14 August 2006 (UTC)


 * I am arguing that the merge could be accomplished by simply deleting the Jockey wheel article. With all due respect for Sheldon Brown, I think his nomenclatural assertions in that article are personal preferences only, for which counter-examples of less strict usage could be found.  And I have suggested that maintenance tips are not appropriate to include in any wikipedia article, but belong instead only in wikibooks.  But I solicit multiple opinions.--SportWagon 21:20, 14 August 2006 (UTC)
 * Alright, even worse, an alternate, and still relatively strict, terminology of jockey wheels, guide pulley and tension pulley is suggested in the current article. (Derailleur gears)--SportWagon 21:23, 14 August 2006 (UTC)

Jockey Wheel Terminology
Okay, I guess we should separate the terminology debate from the actual merge debate. A quick Google ought to convince us that many people use "jockey wheels" (or "jockey pulleys") to refer to the pair of pulleys in question.

Google also led me to a probably useful source of information.
 * http://www.freepatentsonline.com/search.html

At that site, it appears that "jockey" is not used very much at all in reference to bicycles (and in at least one instance did match Sheldon Brown's contention--but in the same reference gave the alternate of "guide pulley"). "guide" and "tensioner" pulleys appear common in the patent descriptions.--SportWagon 21:44, 14 August 2006 (UTC)

Friction shifting versus indexed?

 * With friction shifting, the rider first moves the lever enough for the chain to jump to the next sprocket, and then adjusts the lever a slight amount to center the chain. An indexed shifter has distinct clicks for each gear, and the rider merely moves the lever to the click they want without a second adjustment movement.

I think that passage exaggerates the degree to which you need to over-shift with friction. More realistically, you would frequently do a shift, and then later realize perhaps you needed a fine adjustment. On a particular bike, you might eventually learn to habitually overshift and back-adjust for certain shifts. A casual rider could usually get away without such adjustments, although when riding hard it was important to keep the chain properly centered to avoid unnecessary friction or slippage. The passage also overlooks the fact that achieving that over-shifting is actually a fairly difficult problem in the design of indexed shifting. Bah. I should try a test ride some time. Unfortunately the only bicycle I have ready-to-run without indexed shifting has no shifting at all! I'll think about the above and edit sometime, probably. I should also write off-line and then upload a "Cambio-Corsa/Paris-Roubaix Diversion" section.--SportWagon 18:24, 25 September 2006 (UTC)


 * The amount of over-shifting needed varies depending on the design of the derailleur and freewheel sprockets. With the older ones like Campagagnolo Super Record, you definitely need to over-shift then re-centre, especially if you use older freewheels that don't have modern shaped sprockets, but it's something that becomes automatic after you get used to it. LDHan 21:53, 25 September 2006 (UTC)


 * (Using this as a bit of a scratch-pad...) Over-shifting was more necessary on shifts to larger sprockets.  Shifting to smaller sprockets usually happened before the chain was centered, so you merely needed to cause the clunk, then smooth it out, usually continuing to shift in the same direction.  The Sedi-Sport and similar chains helped a lot before ramped clusters.  Though designed for narrowly-spaced clusters, the Sedi-Sport even worked nicely with old-standard spaced (5-speed) freewheels.  My first setup was a cheap Simplex rear derailleur and and Atom freewheel with a who-knows-what chain.  The levers needed not infrequent tightening while riding, and the rod-mechanism of the front derailleur (it was cable operated, but the cage itself was pushed out on a small rod) occasionally needed a little tap from your toe to persuade it to go back to the small ring.  I seriously think the over-shifting phenomenon is more of a factor in the successful design of indexed systems than it was a conscious hassle for humans.--SportWagon 16:34, 26 September 2006 (UTC)

What Rotor System might have been?
I recently deleted from See-Also:


 * *Rotor system

There is no such article Rotor system. But after thinking about it for a while someone may have been hoping to create and link to an article about "automatic" shifting driven by weights moved by centrifugal force. The name would be too general for such an article, anyway.--SportWagon 16:15, 27 September 2006 (UTC)

Album name "Disraeli Gears" did come from "Derailleur Gears"
Reading Disraeli Gears you see...


 * The title of the album was an inside joke. Clapton had been thinking of getting a racing bike and was discussing it with Baker, when Mick Turner, one of the roadies, commented on the performance of "those Disraeli gears", meaning to say "derailleur gears". The band thought this was hilarious and decided that it should be the title of their next album. Had it not been for the roadie's malapropism, the album would simply have been entitled Cream.

So it wasn't a totally inappropriate link. Not that I feel strongly enough about it to put the link back...

"Just FYI".--SportWagon 17:31, 27 November 2006 (UTC)

A claimed 1930 derailleur
A claimed 1930 (non-racing) bicycle with an example of derailleur gears. Perhaps pertinent to earlier history discussion.--SportWagon 19:11, 29 May 2007 (UTC)

Article needs more basics
I forgot the name of the little wheels in the rear arm. On first scan, I didn't find that info. Later I found it buried at the bottom of the lede section.

The article does not make a strong introduction to the distinction between the front and rear mechanisms. Diagrams would be nice, of course, with the standard components labeled. Both to guide the chain to the selected sprocket and to maintain chain tension by taking up any slack caused by changing to a smaller sprocket, the rear derailleur has two pulleys in a spring-loaded rotating cage, through which the chain rolls in an S-shaped pattern. No one who isn't already familiar with these contraptions will know what the em. phrase refers to. What plane of rotation? On a bicycle, people will first think continuous rotation, not partial rotation. Better described as an elbow with the spring opposing extension. A person unfamiliar would at least have a clue. Doesn't that obstreperous thing have two springs? I sure think so when I'm trying to pop my master link.

No mention at all of lubrication, little mention of maintenance considerations, nor that certain ring spacings don't work, nor any use of the word "width" (corresponding to chain selection). MaxEnt (talk) 03:26, 13 April 2008 (UTC)

Question about pressure on pedals
In the relaxed position paragraph it says it may be difficult to ease off pressure from the pedals... My question is: what relevance does the pressure on the pedals have on changing rear sprockets? I would understand this comment if it was about the front derailleur. Front sprockets are fed from above, where the tension in the chain comes from the pressure on the pedals. But rear sprockets are fed from below, where the tension in the chain is provided by the tensioner spring, not the pedals. Why would having pressure on the pedals make changing rear sprocket more difficult? 130.234.5.137 (talk) 01:18, 16 April 2008 (UTC)

Actuation ratio, shift ratio, and pull ratio
I edited the Actuation ratio section of the article to say that the 1:2 vs 1:1 ratios are normative. I should have waited until I got a quality reference, as that contradicts what SRAM says (all marketing hype), but I am confident that it's true. While I'll continue to look for a quality reference, I do have some references, I just don't think that they are good enough to use. I also have a logical argument. To quote "SRAM actively promotes their 1:1 shifters and derailleurs, which have about twice as much cable movement as those by other manufactures." Berto, Frank; The dancing chain. My emphasis. It's said in passing, and I don't think it's a strong reference, even coming from a solid source like Berto. Also in the same book (p294) is a diagram of the indexing cam on a suntour deraillure. Here's where my logical argument comes in: As a deraillure parallelogram swings from low to high gear the angles of the parallelogram change, as does the angle between the housing stop on the deraillure, and the anchor bolt. This change between these two changes the actuation ratio. It is mensurable with rudimentary tools that the shifter moves different amounts of cable for different gears to balance this and have the deraillure move a constant amount between different gears. The diagram on page 294 clearly shows the detents becoming further apart as it shifts from the "top" to "7th" gear. I'm leaving it with the "nominative" statement for now, but would like to put in some more info on this later, when I find some more references. That is if this is a strong enough argument.--Keithonearth (talk) 10:08, 9 January 2009 (UTC)


 * For a detail like that, I bet that is as good as you are going to get. It is good enough for me. Any chance of taking a picture of a shifter? -AndrewDressel (talk) 12:20, 9 January 2009 (UTC)

The actuation ratios have been reversed recently in these edits (for example Shimano has been changed from 2:1 to 1:2, and even the quoted text in one reference has been changed so that now it conflicts with the quoted text in another reference). Since I don't see any new references to support this change, I am reverting the entire mess. It is one thing to say that an existing reference is sub standard or to provide competing references, but simply to change the quoted text from an existing reference without even so much as an edit summary seems to go against both wp:rs and wp:nor. -AndrewDressel (talk) 15:28, 29 August 2011 (UTC)


 * The OR tag has been up for more than 6 years and now someone has inserted "shift ratio is the reciprocal of actuation ratio and is more easily expressed for derailleurs than actuation" without a reference. "Shift ratio" has about twice as many hits on Google (64,000) as "actuation ratio" (34,000), but many are not related to bikes, the rest all appear to be blogs and forums, and many even use the same phrasing. Worse, it appears that the best sources, Frank Berto, Sheldon Brown, or John Allen, don't even use any of the terms. I believe it is time for a major rewrite to something like this:


 * The ratio, sometimes called the actuation ratio, shift ratio, pull ratio, shift activation ratio, or just ratio, between how far the shifter moves the shift cable and how far the shift cable moves the derailleur, or its reciprocal, is an important parameter for derailleurs and indexed shifters. There are currently several standards in use, but in each case the distance the derailleur moves must equal the spacing of the sprockets. The following standards exist.
 * The Shimano compatible family of derailleurs is stated as having a shift ratio of two-to-one (2:1), and since SRAM makes two families of components, the term has been widely adopted to distinguish it from SRAM's own one-to-one (1:1) ratio family of derailleurs. Notice that these family names do not give the exact shift ratios: the 2:1 shift ratio is in fact about 1.7 (Or 1.9 on the Dura Ace series up to 7400) rather than 2, and the native SRAM shift ratio is about 1.1. The family names of these standards are reversed by some. Thus, in Shimano systems a unit of cable shifted causes about twice as much movement of the derailleur.
 * The native SRAM convention is called one-to-one (1:1). These have actual shift ratios of 1.1. A unit of cable retracted at the shifter causes about an equal amount of movement in the derailleur. SRAM claims that standard makes their systems more robust: more resistant to the effects of contamination. Some SRAM shifters are made to be 2:1 Shimano-compatible, but these clearly will not work with SRAM's 1:1 derailleurs.
 * The Campagnolo convention. The shift ratios are 1.5 for modern units but their old units had 1.4 ratios.
 * The Suntour's convention.
 * Shifters employing one convention are generally not compatible with derailleurs employing another, although exceptions exist, and adaptors are available.


 * Objections? -AndrewDressel (talk) 15:40, 31 December 2018 (UTC)