Talk:Clutch

Clutch plate wear
Since I'm not a mechanic and don't truly understand how this works, I didn't change this, but the following sentence doesn't jive with what I do know about clutch operation:


 * When the right-most pedal (the accelerator/gas pedal) is pressed while the clutch pedal is being let out, the clutch plates wear out faster than normal, but this is often used for a hard launch.

Is it possible to shift into first gear without, at least for a short while, both pressing down clutch and accelerator? Simply releasing the clutch and THEN accelerating will stall the car. Trying to shift into gear and accelerate without pressing down on the clutch has the same result. So, this sentence seems wrong, but I'm allowing my stupid mind the benefit of the doubt. Can someone explain this? siafu 22:15, 16 May 2005 (UTC)


 * You are right, and I reworded the article to get this described better. &mdash;Morven 22:54, May 16, 2005 (UTC)


 * Phew. siafu 23:04, 16 May 2005 (UTC)

Clutch material
I'd like more information on what material clutches are made out of -- it just says "brake like material which used to be asbestos" but it doesn't say what it is now. The "Brake" article also fails in this regard, not discussing at all what modern friction brake materials are.

21/03/06 - Fixed a small grammar error.

August 1, 2006 - This may offend some baseball fans, but I removed David Ortiz's name from the article.

Diagram may be misleading.
Although I'm sure the first author understands the operation of a diaphragm spring, the diagram in the article may be misleading to readers unfamiliar with clutches. It seems to suggest that the throwout bearing is pushed to engage the clutch, when the opposite is actually true.

During assembly, the clutch disk is sandwiched between the flywheel and the pressure plate assembly. As the bolts that mount the pressure plate assembly to the flywheel are tightened, the diaphragm spring is put in compression as it firmly pushes the clutch plate against the flywheel.

The diaphragm spring is fixed to the pressure plate assembly cover at about 80% of its diameter, as because of this, works like a teeter totter. When the throwout bearing pushes the inside diameter of the diaphragm in towards the flywheel, it pulls the outside diameter out away from the flywheel, releasing the pressure on the clutch plate.

Perhaps I can make a cross-sectional diagram that would make this easier to understand.

One other small correction, in automotive and truck clutches, there are two type of torsional damping designs:

1. The most common, and the one the article mentions, is to  have springs or rubber bushings between the clutch plate and it’s hub that allow a small amount of rotation between the two.

2. The other, not as common design, is to use a solid clutch disk / hub without springs against a two-piece flywheel, also called a dual-mass flywheel. The two flywheel masses have springs between them which perform the same function, damping torsional vibration. This design is more common in luxury cars and trucks.

John Thomas Pawlak 05:45, 14 December 2006 (UTC)


 * 17-Oct-2007: I've fixed the diagram description, adding, "At rest, all 3 rings connect, with no gaps" (diagram shows clutch lever pressed). -Wikid77 03:53, 17 October 2007 (UTC)

Editing what I typed, earlier: Nikevich (talk) 11:22, 21 November 2011 (UTC)

Rings? That's downright puzzling; sorry. After a month or so, I realize that "rings" referred to discs. Rings have big holes through them, such as finger rings (jewelry). Nikevich (talk) 11:22, 21 November 2011 (UTC)

(Please read first! --Nikevich):

In the following, I've interspersed comments into my text that make its editing history (probably) miserably-difficult to follow; I'm not sure just what to do. After deciding to remove the illustration, I discovered the video at HowThingsWork, which combined with Mr. Pawlak's explanation to point out a quite-clever and non-obvious aspect of design probably found only in car clutches. Although Mr. Pawlak offered a clear explanation, the animation in the HTW video clarified an unexpected and non-intuitive feature of design that truly begged for explanation. Nevertheless, I stick with my decision to remove the illustration; probably its worst aspect was the very-misleading extreme separation of the three elements — flywheel, clutch disc, and pressure plate (iirc!). The video makes quite clear how closely-spaced they are. Not to be over-dramatic, I do hope that this mess is not a symptom of early Alzheimer's disease (I'm 75, and my mother's sister died of it.) On further thought, a generic clutch is significantly simpler in concept than that in a car. We do need a more-generic illustration. Apologies for one heck of a mess — Nikevich (talk) 11:22, 21 November 2011 (UTC)

The diagram, even though it looks nice, surely seems to have serious technical errors (as I pointed out in the Talk page for the diagram) and omission of essentials, such as springs that keep the plates engaged. (Added comment, 2011.11.21): After seeing the video at HowThingsWork (link below), Mr. Pawlak's description finally "took root" in my mind. Indeed, a good video can be worth 10,000 words.) Nikevich (talk) 11:22, 21 November 2011 (UTC)


 * Following text, typed earlier, shows my previous ignorance. However, clever design, as made clear in the animation at HowThingsWork, really begs for explanation. Without Mr. Pawlak's explanation, the illustration looked even worse. Nikevich (talk) 11:22, 21 November 2011 (UTC)

(Following, which is incorrect, is a consequence of inadequate understanding and explanation:) As shown, granting that the elements are much farther apart than is the actual case (for clarity), force on the vertical lever would squeeze the plates together (although the tapered brown springs look really delicate), which is just the opposite; the pedal disengages the clutch -- it doesn't engage it. (Nikevich, probably 17 Oct. 2011)

Following is from 21 Nov 2011:
 * After considering it for a month, I removed the illustration.

I assume that it has been archived, in case my decision is reversed. It's hard to type my reasons without being severely negative. It has haunted me, off and on, for the past month. The artist is a capable illustrator, but I find it hard to believe that he has had any experience with practical automotive mechanics, and perhaps not with mechanisms, in general. Again, this is not personal in any sense; it's strictly a matter of technical competence. I removed it because it differs from reality in several important respects, to the extent that it significantly mis-informs the viewer. Mis-education is not Wikipedia's mission, for sure! I could suggest Tom and Ray Magliozzi of NPR's "Car Talk" radio show (produced in Boston and/or Cambridge) as very-intelligent (MIT graduates, iirc) evaluators. Any competent car mechanic should have a worthy opinion.

Further thoughts: Although not perfect, in the video, here, there's quite a good (brief) animation and decent dialogue by a practical mechanic:  (That's a front-wheel-drive transmission, btw; they should have explained that.)

What was not explained there was the clever way the "petal" springs of the pressure plate operate; that really needs further clarification, and, belatedly, I realize that this probably confused the technical illustrator. Failure to explain how the springs effectively reverse actuator direction (??) was a crucial failure in the illustration. My own ignorance of this clever design hasn't helped matters. If, by any chance, that HowStuffWorks animation can be licensed for Wikipedia, that would be very helpful. I could write the description, without being too inaccurate.

In perspective, while automotive clutches are ubiquitous, in mechanical engineering, there are numerous different designs, probably numbering in the thousands. IIrc, I tried to point that out in editing the article, some time ago.

I have been interested in mechanisms for about 71 years, although I'm not an expert, but, from a considerable degree of self-education (mechanical analog fire-control computers being the exception) and lifetime interest, I do know something about practical matters. (Full disclosure: I have been notably un-involved in practical aspects of automotive mechanics!)

Sorry to take drastic action, but this was just too far beyond the pale.

Best regards, Nikevich (talk) 10:42, 21 November 2011 (UTC)

With further updates (making this, more than likely, an horrid mess to follow, for which I apologize!) Nikevich (talk) 11:22, 21 November 2011 (UTC)

Imho, it seriously needs a look by a competent mechanic. Again, nice illustration, but... Nothing personal; I know nothing at all about the author. Nikevich (talk) 06:37, 13 October 2011 (UTC)

Very complicated
This article seems to have been written by a mechanic. Anyone able to clarify it and dumb it down a bit? The intro is also too short to provide any context that is useful. Lasdlt 02:21, 23 April 2007 (UTC)

Snoop Dog Teeth
"These cogs have matching teeth, called snoop dog teeth, which means that the rotation speeds of the two parts have to shizzle to the nizzle homie match for engagement." - I'm no mechanic but I'm sure this is a vandalising edit. —The preceding unsigned comment was added by 82.46.47.9 (talk) 14:35, 4 May 2007 (UTC).

Slipping Clutch?
How does it occur? Professional Gamer 21:43, 17 June 2007 (UTC) how does it occur? — Preceding unsigned comment added by 14.140.86.157 (talk) 11:48, 22 May 2013 (UTC)

3D Diagram
Is absolutely horrible. Like a person above said, it doesn't really illustrate how a clutch is assembled and functions. —Preceding unsigned comment added by 68.199.99.210 (talk) 02:52, August 28, 2007 (UTC)

Horrible? Although it's pretty, and the illustrator has some ability, it is horrible. Being a believer in Wikipedia, I'm appalled that it has not been fixed for several years! Sorry to use strong language, but imho it's merited. Nikevich (talk) 06:45, 13 October 2011 (UTC)


 * Also, the text blends in with the background at the top. —[74.202.89.125] 17:18, 7 September 2007 (UTC)
 * 16-Oct-2007: I overlayed a bright label "Flywheel" at the blended-top, where text was too dark to read, using Template:Location_map to treat the clutch-diagram like a map with an overlayed label. -Wikid77 03:33, 17 October 2007 (UTC)

Sorry, although I don't know some details, it surely looks as though it has serious errors and probably some significant omissions. I commented above, already. Compare it with photos and diagrams in a well-written, reliable book about cars, please. Nikevich (talk) 06:41, 13 October 2011 (UTC)
 * 16-Oct-2007: I have enlarged that 3D clutch-diagram, adding a long caption which explains the operation between components in the diagram. A picture might be "worth a thousand words", but it's a different thousand to each person who sees the picture:  so, the caption adds a description of how the various components interact. -Wikid77 02:49, 17 October 2007 (UTC)

Friction Clutches - Load
I don't understand this subsection at all. —Preceding unsigned comment added by 205.67.232.56 (talk) 15:37, 28 December 2010 (UTC)

History of the clutch?
When, where and by whom was the clutch created? Is that information even known? 67.233.238.244 (talk) 05:14, 19 October 2011 (UTC)

Exactly, I came here to learn about the history of the clutch, but there is no history section. If anyone knows about the history of the clutch, please add a history section. Thanks. FreeFlow99 (talk) 12:35, 21 August 2016 (UTC)

What does this mean?
"The opposite component of the clutch is the brake."

What? The term "opposite" is not well defined in this context. Maury Markowitz (talk) 14:26, 2 March 2012 (UTC)

Automotive-Centric
This artcle is very automotive-centric, and in places assumes a lot of knowledge on the part of the reader, e.g. the clutch damper subsection in the Friction Clutches section does not actually state what a clutch damper is, i.e. that a clutch damper is a device that softens the response of the clutch engagement/disengagement. I'm going to add this sentence for a start Crobarcro (talk) 10:10, 24 July 2013 (UTC)
 * That's a point that could be made about many WP articles. If you have the (substantial) time and inclination to do so, then this could easily be split into two articles on clutches and automotive clutches (in the narrow sense of manual transmissions). There's plenty of scope and sources to support both. Andy Dingley (talk) 10:52, 24 July 2013 (UTC)

Languages system does not work
https://en.wikipedia.org/wiki/Coupling is disallowed to link to German https://de.wikipedia.org/wiki/Kupplung as https://en.wikipedia.org/wiki/Clutch already does. Obviously this restriction does not work in the real world. So you English folks either need to reduce your vocabulary to match all other languages in order to make language references work... or just allow multiple mappings! — Preceding unsigned comment added by 2003:8C:2F00:B500:A030:2B2A:A43F:D761 (talk) 10:48, 28 April 2017 (UTC)

Angular velocity or velocity?
I think the following sentence in the section Multiple plate clutch is wrong:

"In motorsports vehicles that run at high engine/drivetrain speeds, the smaller diameter reduces rotational inertia, making the drivetrain components accelerate more rapidly, as well as reducing the angular velocity of the outer areas of the clutch unit,"

Wouldn't the angular velocity be the same(assuming the rpm stays the same), but instead the velocity of the outer areas be different?

Owdeou (talk) 16:18, 7 October 2017 (UTC)

Proposed new opening sentences
The current opening sentences seem to have been written by someone who really knows the subject, but who doesn't critique their own writing very well. I don't want to delete it, but at the same time I suspect that it's impossible for many people to make use of. Here's my proposed new start:

[I am neither a mechanic nor a physicist, so please edit the hell out of this to correct my mistakes.]

A clutch is a part used in some machines that do mechanical work. In such machines, force is normally applied by the machine onto an object; the clutch (if one is present) mechanically disconnects and reconnects moving parts, without stopping the machine, to allow an operator or automated system to pause and resume that application of force. TooManyFingers (talk) 23:45, 7 August 2021 (UTC)

Dry Clutch
Under the "Dry Clutch" section, it says:

"A dry clutch uses dry friction to transfer power from the input shaft to the output shaft, for example a friction disk pressing on a car engine's flywheel."

I don't entirely understand clutches, but wouldn't the disk be pressing on the clutch casing, and not the flywheel? Furthermore, is the clutch always attached to the flywheel? Keppin330 (talk) 00:03, 7 August 2023 (UTC)
 * A clutch is different from a brake, in that a friction clutch needs to press on two items, both of which are rotating. That's a harder design problem than a brake, where a stationary object presses on a rotating one. Usually it involves some form of bearing. It's also a reason why preselector gearboxes were favoured in the 1930s–1950s, as they used brakes as a wear item rather than clutches, and these brakes were easier to maintain.
 * For use with an engine (the typical road vehicle layout) the engine will have a flywheel and that's a convenient large, strong disc for the clutch to act against. In a few cars (Alfa Romeos, Porsche 924), there is a transaxle layout instead and the engine and clutch are separate. This requires a separate plate to be provided, just for the clutch to act upon. Andy Dingley (talk) 15:35, 7 August 2023 (UTC)