Talk:Derailleur

High-normal/Low-normal
I think these belong in a separate article due to their proprietary nature. These are Shimano marketing/design constructs that should be titled as such, and they cloud the description of typical derailleurs (spring-loaded toward the low gears). MM962 (talk) 21:28, 6 February 2009 (UTC)

Also it was introduced by Shimano way before, XTR RD-M951 1998 groupset, so introduced in 1997 so edited that with references --Bensimmo (talk) 16:39, 27 August 2009 (UTC)

SunTour had a low-normal derailleur in 1965! http://www.disraeligears.co.uk/Site/SunTour_New_Skitter_derailleur.html 70.237.195.39 (talk) 03:30, 18 April 2010 (UTC)

The low-normal statement (that Shimano invented in 1998) is clearly incorrect. Sheldon Brown (who's commonly referenced in bike-related wikipedia articles) states that low-normal predates high-normal derailer design. http://www.sheldonbrown.com/gloss_l.html#lownormal Besides that many of us have seen older low-normal derailleurs in our lives.

Simplex, Huret, and Benelux all had plunger-action rear derailleurs as far back as the 1930's that shifted to low gear on relaxation of the cable. These were still fairly common on low-end bicycles as recently as the early 1960's. I doubt that there was any intent to achieve some putative benefit; rather this was merely a consequence of the way it worked. In fact, on anything larger than a 24 tooth sprocket, shifting could be problematic, as the spring tension was at its lowest when the most force was needed. Wschart (talk) 01:21, 2 September 2010 (UTC)

Unsure of why the article claims "rapid rise" to originate in 2004. This proprietary Shimano function originated in 1998 with M951 as Bensimmo noted last year. The reference cited for the 2004 origin actually does not say anything of the sort. I will update now with proper citation from http://members.home.nl/children-of-the-korn/XTR950.htm 98.184.135.243 (talk) 03:05, 6 September 2010 (UTC)

"Gears" versus "sprockets."
Referring to the opening of the article, I think there's a misunderstanding about what we mean when we talk about bicycle gears. We're not suggesting that the sprockets are gears. We're talking about the gear ratios created by sprockets with different numbers of teeth being connected by a driving chain. Maybe we should talk about a 10-ratio machine rather than a 10-gear one, but I've never heard the sprockets described as anything else (except, collectively, a "block"). I didn't change anything, but I do feel the existing wording is a bit unnecessary, clarifying something which maybe doesn't need it. Pavel (talk) 17:50, 13 February 2009 (UTC)


 * It seems to me that the we should acknowledge that the term "gears" is used flexable in the bike world to refer to both the gear ratios, and the individual sprockets, but that we should favour more technically accurate terminology in the article as more encyclopedic. And stick to using the terms "gear ratios" and sprockets in the intro. --Keithonearth (talk) 07:40, 14 February 2009 (UTC)


 * I agree with Pavel. In the bicycle world, 'gear' is synonymous with 'gear ratio'.  As such it is determined by two sprockets (cogs) not one, and should never be used to refer to a single sprocket.  We should make that clear by defining the term in the intro.  Then, like Keith suggests, endeavor to use the correct terms in the body of the article. I made a similar change to the intro in Bicycle gearing.  I think - at least for now - a simply change in the last sentence of paragraph one might do it, but let me read the rest of the article before I commit myself. --Dmforcier (talk) 20:05, 17 August 2009 (UTC)

First Parallelogram Rear Derailleur
The article as it now is credits the Campognolo as creating the first parallelogram RD in the early 1950s. It has a blog entry as a reference:. I'm trusting a published book over that, and change it to say that Campy introduced the first commercially successful parallelogram RD, and some other details. Frank Berto, in The Dancing Chain, specifies that Nivex and JIC made parallelogram RDs and Francesco Ghiggini had a pre-existing patent. --Keithonearth (talk) 08:50, 23 February 2009 (UTC)

The article Title is incorrect
Technically, "Derailleur Gears" is an incorrect term since there are no gears on a bicycle. (A "gear" in BikeLand is short for "gear ratio". We've started to make this distinction clearer in Bicycle gearing and edit for proper usage.) I suggest that "Bicycle Derailleur Drivetrains" is a better title. Actually, I'm not happy with the organization of the general topic. Seems to me that there should be an encompassing article Bicycle Drivetrains that includes this article, Bicycle Gearing, etc.. - generally with the content abstracted in the 'Drivetrains and gearing' in the main Bicycle article. Where is the proper place for that discussion? Dmforcier (talk) 16:26, 18 September 2009 (UTC)


 * I oppose changing the article name, and incorporating planetary hub gears into it. Both articles have enough info in them to stand on their own, and mixing them would only make it harder for users to navigate and for editors to organise.  The term gears as an abbreviation for gear ratios is an old one, that goes back to the first bicycles that have multiple gear ratios.  It is a useful and understood convention, that is used by cyclists from the most novice to the most experienced.  We have no reason to avoid it.  --Keithonearth (talk) 18:18, 18 September 2009 (UTC)


 * That makes sense in a general article on bicycle gearing, but this article is (or should be) about the derailleur mechanism. General theory of gearing - independent of the mechanism employed - does not belong here, nor in other articles about transmission mechanisms such as Hub gears.  To that end let me suggest another title for this article: "Bicycle derailleurs".


 * After some thought I agree with you that there should be separate articles about the types of transmissions. But I firmly believe that there should be an umbrella article discussing theory and tying them all together.


 * I also think the question of large-scale organization should be considered by a wider audience than those few who watch this article. So what's a better place to discuss it? Dmforcier (talk) 23:06, 26 September 2009 (UTC)


 * Sorry if I dismissed your ideas quickly in my last post. While I would not like to see the internal gears incorporated here, I would be open to talking about changing the name of the article to bicycle derailleurs.  As for a more central place to post a note about overall organisation Wikipedia talk:WikiProject Cycling would seem to be a good place to me.  Anyone who's part of the Cycling WikiProject is likely to see it.  I can see how an article on "Bicycle drivetrains" could be a useful thing, I'd expect if you got it started then it would draw attention.  --Keithonearth (talk) 03:46, 27 September 2009 (UTC)


 * Thanks. I still think a name change is warranted, and while I also think the umbrella article with sub-articles is a good idea, I'm not eager to volunteer to do it. ;) But maybe I'll take up your suggestions. Thanks. Now, how do we go about getting approval for a name change? Dmforcier (talk) 21:43, 24 May 2010 (UTC)


 * I'd agree with changing the name to just Deraileur, which already redirects here. That way the user doesn't have to guess what second word (mechanism, gears, bicycle, etc.) we chose. Is there a need to disambiguate? -AndrewDressel (talk) 21:54, 24 May 2010 (UTC)

top-pull vs bottom-pull front derailleurs

 * Full suspension MTBs seem to need bottom pull designs as (a) the routing will be stable and (b) keeps the cabling out of the way of any rear suspension. Certainly that holds with the one I have looked at; we'd need to go through more datasets (bike shops) to be sure. One big complication of FS bikes is that the mount almost needs to be below the chainrings, rather than above it, so that various pivoting chainstays don't come into contact.


 * Recent MTB derailleurs appear to have routing to support top or bottom pull, as mentioned in the article. Interestingly, this makes them heavier. So why have them? I suspect it may be to reduce stock keeping units in the bike shops, the risk of someone ordering the wrong part, and reduces manufacturing costs by having only one thing to make. Any hard data here would be useful. SteveLoughran (talk) 18:15, 5 April 2010 (UTC)

Hub gears et al.
There is (or was) a rather lengthy section on hub gears that sounded like it was written by a hub-gear salesman. I removed most of it. First, there is a full article on hub gears. The info in the section was either duplicated or belonged there. (if not in that article, why not?) Second, the section was so intent on telling you why hub gears are better that it never even told you what they are! Third, the section is totally off topic. [Kindly read the article name.] I'm in favor of removing even the heading, since nothing about hub gears is pertinent to this article. Opinions?

Also, I moved the 'Using' section to below 'Modern' section. The History and Modern sections are written to flow from one to the other and Using simply got in the way. I'm not all that thrilled that it now appears so late in the article, but it would take some re-write to make it work. (Not that a re-write isn't needed.) Dmforcier (talk) 21:34, 24 May 2010 (UTC)


 * It's gone. Dmforcier (talk) 20:56, 4 June 2010 (UTC)

Removed Electronic FD pic
I suppressed the pic of an electronic FD for two reasons: 1) it runs across three main sections and just looks sloppy. 2) It is the lead picture of the Electronic Gear-Shifting System article referenced right next to it, and only one click away.

Andrew, do you really think there's plenty of room for it? Look at the page layout. I'll leave it up to you. Dmforcier (talk) 21:54, 24 May 2010 (UTC)


 * I don't know of any requirement for pictures to fit inside a single section: even the first picture runs past the end of the history section. Since we have no control over the screen size, resolution, or font size that our readers use, we have pretty limited control over how any page will be rendered. I also don't see the fact that the picture is used elsewhere as relevant. It is a picture of derailleur after all, of a type not pictured elsewhere in the article, not a hub gear or something else off-topic. I actually did look at the page layout before I restored the picture. Why would you suggest that I didn't? On my monitor, at 1600x1200 resolution, there is a sea of text and I can just barely arrange the page so that only part of the picture in question is visible at the same time as part of the closest other picture. I expect the situation to be even more so on my laptop. That is how I would define "plenty of room". If there came a time when the article was crowded with great derailleur pictures, I would agree that it isn't the best picture in the world, but we are far from there at this point. -AndrewDressel (talk) 22:34, 24 May 2010 (UTC)

Chain deflector add-ons
In an effort to head off even the appearance of edit warring, I'm moving the discussion of the suitability of this section to here: So, with more room than just an edit summary, this is the case for including the material: Since there is plenty to support this section having its own article, except perhaps quantity of material, would that be a less-objectionable solution to this dilema? -AndrewDressel (talk) 15:41, 6 September 2010 (UTC)
 * "Remove commercial sponsorship for an unusual and low-demand add-on." - 06:49, 23 August 2010 MalcolmMcDonald (talk | contribs)
 * "Sources are reliable. Entire article is about commercial products." - 17:07, 23 August 2010 AndrewDressel (talk | contribs)
 * "Add-ons to control a problem that top mechanics supposedly cannot control contribute nothing to the sense of the article and look like commercial abuse of the page." - 08:54, 5 September 2010 MalcolmMcDonald (talk | contribs)
 * "Material is appropriately sourced and no more commercial than the rest of the article. It is all about products manufactured for sale." - 11:28, 5 September 2010 AndrewDressel (talk | contribs)
 * It is notable. Sheldon Brown describes it and explains its necessity in his glossary. Both Bicycling Magazine and Velo News have written about it. Neither being usual nor being in high demand are criteria for inclusion.
 * It is well sourced with verifiable and reliable references that are well known in the industry.
 * There is no commercial sponsorship or slant to the section nor has there been. There are no links to companies that manufacture or sell the products. No product names nor manufacturer names are even mentioned.
 * It is not receiving undue weight. "In determining proper weight, we consider a viewpoint's prevalence in reliable sources, not its prevalence among Wikipedia editors or the general public."
 * We're informed that there is a problem with derailleur gears over-changing and the chain falling off - to the extent this is a problem, it looks much like a temporary oversight by the manufacturers (Shimano etc). Outside interests have seemingly leaped onto this "problem" and are flogging a solution that is totally low-tech, plastic spacers we'd all be better off fashioning with our pen-knives.
 * Therefore, I don't believe we should be commenting on this relatively trivial failing of some forms of derailleur gears (basically on behalf of commercial interests, since we're advising a paid-for solution, not an adjustement or any rider-modifying behaviour).
 * I say this in the full knowledge we're ignoring much bigger and more intrinsic problems with derailleur gears - eg we're not mentioning the intrinsic weakness of derailleur chains, the barrel-shaped pins that allow them to twist and bend and come apart.
 * In fact, the whole balance of this article needs changing to bring it more in line with the article on hub gear systems, where an entire "disadvantages" section has been added, and into which has been shoe-horned facts that, in many cases, are completely irrelevant (eg the unsprung weight claim). It's particularly bizarre to see this bias at hub gear, since the bias so unnaturally introduced is, in this case, in favour of the cheaper solution and against the technologically complex and more expensive device. MalcolmMcDonald (talk) 19:23, 28 December 2010 (UTC)

Efficiency of deraileurs
It would be good to have a look at how the two cogs in derailleurs affect efficiency, and also how having the chain not perpendicular to the axis of the sprockets affects it. It is claimed by fixed gear riders that fixed gears are more mechanically efficient, but I'd like to see a number put on that, as i suspect its less than 2-4%. Also, because chain efficiency is related to the curvature of the sprockets (smaller sprockets bend the chain more and so it operates less efficiently), derailleurs are more efficient in that sense than fixed gears. but by how much? — Preceding unsigned comment added by Dazalc (talk • contribs) 01:59, 25 August 2011 (UTC)


 * I'm currently looking into this question of gearing efficiency in Bicycle gearing and have specifically bought several relevant books covering the topic. The information currently in that article appears to match the references, but I think there is scope for providing more detail. Murray Langton (talk) 07:41, 25 August 2011 (UTC)

Error of Understanding
The shift ratio is the length of cable pull divided by the transverse distance shifted by the derailleur cage; it is not merely about the distance that the shifter itself moves, since some rotate and some use gearing in themselves; or indeed the amount of non-specific movement of the derailleur itself.

I have attempted to correct the matter on a number of occasions only to have the changes reverted. I have also attempted to introduce some context to the shift ratio matter too, but I assume that this is a bit too useful for inclusion.

May I suggest that before assuming self-styled professorial status, that the guilty parties at least write down the correct facts. Ronpedia (talk) 11:40, 22 September 2011 (UTC)


 * I'd be interested to hear your point of veiw Ronpedia, but referring to other editors as "guilty parties" and telling them to just write down correct facts is detrimental to coming to consensus. Remember that everyone makes mistakes. I'm not sure what you would like to see it changed to, please tell us more here.  Are you saying that it's not important how far the shifter travels but only how far the head of the cable travels?  (I've not sifted threw the history of the article to see what you've but in. --Keithonearth (talk) 04:30, 23 September 2011


 * As I have written on your user page, you must provide reliable sources for the assertions you add. Without that, the details you add are merely your own definitions or original research. On at least one occasion you have gone so far as to change the quoted text from a source, so I feel that I have no choice other than to examine your edits with a critical eye. If you can provide a reliable source for your definitions, please do so. If not, please stop your disruptive editing. In any case, it would be helpful if you provided an edit summary to explain what you are changing and why. -AndrewDressel (talk) 14:42, 22 September 2011 (UTC)


 * Apologies for my obvious error in the first line of this point.  As I understand it, and in general, actuation ratio is an input quantity divided by the quantity of the effect caused by it.   In bike terms for most derailleurs, it is clearly the cable pull divided by the transverse shift (inter-cog spacing).   Shift ratio is the reciprocal of actuation ratio, used for systems, no doubt, that result in awkward fractions for actuation ratios.   The family names of 2:1 or 1:1 refer to shift ratios of the families, and were adopted by SRAM to distinguish their Shimano compatibles from their Native SRAM product compatibles, (of no use to Shimano itself, who use only one family of products for rear shifting).   Expressing the ratio as 1:2 instead of 2:1 is simply a way of stating them in terms of actuation ratios instead of shift ratios and need not be a problem provided that the point is made clear.   The shift ratio for the 2:1 family is in fact about 1.7 and for the native SRAM 1:1 family is about 1.1.   See the bicycles maintenance work in Wikibooks for very detailed pages on the subject.   Thanks, Ronpedia (talk) 09:53, 26 August 2012 (UTC)

'Derailleur' vs 'Derailer'
Why is this argument here? Mentioning that someone is trying to change the spelling to something simpler seems notable - mentioning that they're unsuccessful seems argumentative and un-encyclopedic. 173.13.137.19 (talk) 23:47, 5 February 2015 (UTC)


 * Mentioning that someone is trying to change the spelling of something, without mentioning that they have not yet been successful, seems to be supporting them and un-encyclopedic. -AndrewDressel (talk) 02:41, 6 February 2015 (UTC)

External links modified
Hello fellow Wikipedians,

I have just modified 1 one external link on Derailleur gears. Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. I made the following changes:
 * Added archive https://web.archive.org/web/20081205181751/http://www.users.globalnet.co.uk:80/~hadland/page35.htm to http://www.users.globalnet.co.uk/~hadland/page35.htm

When you have finished reviewing my changes, please set the checked parameter below to true or failed to let others know (documentation at ).

Cheers.— InternetArchiveBot  (Report bug) 10:44, 11 December 2016 (UTC)


 * checked Murray Langton (talk) 17:05, 11 December 2016 (UTC)

External links modified
Hello fellow Wikipedians,

I have just modified 2 external links on Derailleur gears. Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. I made the following changes:
 * Added archive https://web.archive.org/web/20080602002354/http://cycle.shimano-eu.com/publish/content/cycle/seh/nl/en/technical_service/faq_s/general_faq_s/what_is_the_difference2.html to http://cycle.shimano-eu.com/publish/content/cycle/seh/nl/en/technical_service/faq_s/general_faq_s/what_is_the_difference2.html
 * Added archive https://web.archive.org/web/20110823000655/http://www.sram.com/sram/road/technologies/187 to http://www.sram.com/sram/road/technologies/187

When you have finished reviewing my changes, you may follow the instructions on the template below to fix any issues with the URLs.

Cheers.— InternetArchiveBot  (Report bug) 11:36, 14 January 2018 (UTC)

Clutches
I think that someone should add info on rear derailleur clutches. They’ve been out for several years now. — Preceding unsigned comment added by 2604:6000:7607:C200:1127:416E:8ED4:BDB (talk) 01:41, 25 May 2018 (UTC)


 * Started -AndrewDressel (talk) 13:08, 22 October 2018 (UTC)

lede picture
I think the picture in the history section, of a "modern road bicycle drivetrain" should be moved to the lede, as it matches the scope of the article better than the Shimano 600 FD now in that position, and because it doesn't belong in the history section anyway. Unless maybe is there a preference for photographs over drawings?

I do like the front derailleur picture and have no particular opinion on where it should go.

Ccrrccrr (talk) 00:42, 22 January 2019 (UTC)