Talk:Manual transmission

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Contents 1 misc 2 Ratio Manual/Automatic? 3 Semi-manual Inaccuracy 4 Talk Cleanup 5 Really? 6 One disadvantage is questionable 7 Advantages (revisited) 8 Right-of-Way in Europe 9 Spelling Question 10 Informative article 11 Automatic licence 12 Auto v Manual 13 Sliding mesh gearbox are still usual in trucks? 14 three on the tree,confusing 15 taxis

[edit] misc

I added a bunch of "citations needed." This topic is as fiery as religious topics, and if I'm to win an argument to convince my friends why manual transmission is better, I'd like some hard stats from reputable sources to fall back on. Please don't view this as a smear campaign--I want hard info to put the nail in the coffin.--JECompton 18:21, 7 June 2006 (UTC)

I added a References section and the first citation, using footnotes. --KazKylheku 20:51, 7 June 2006 (UTC)

I looked on Consumer Reports' site, but since I don't have a subscription, I can only view the free articles. Still, they did say at the bottom of this link that manuals "provide better performance and fuel economy than automatics", but this is more of a feature article than some hard data. One can easily compare standard vs. automatics of the same model and see the better mileages for standards across the board. But the automatic camp argues you have to have the skill of a NASCAR driver to see these averages. I'll keep looking... --JECompton 21:12, 7 June 2006 (UTC)

That was a good idea, this topic to me sounds a little biased in a few places (such as advantages), i'm not saying those advantages are incorrect its just the way they are presented to the reader that slightly sounds biased (though I noticed through the revisions this has gotten better). Robert Maupin 12:47, 14 July 2006 (UTC)

Do you have any info on semi/tractor-trailer gearboxes? I've heard they can have many, many more gears like 20 or something, and also that the position of the stick can correspond to multiple gears e.g. epending on upshifting or downshifting? Thanks! Ewlyahoocom 09:27, 30 July 2005 (UTC)

Can I suggest that we revert to the non-Unicode diagrams? The Unicode versions don't work on some browsers (I can see all the right characters, but their widths are not constant so the columns in the diagrams don't line up). --Heron 19:21, 6 August 2005 (UTC)

Tractors can have up to a quamillion gears. Heavy duty transmissions can have HI and LOW ranges on the transaxle, which means you can effectively select 2 gears from any shifter position (HI/LOW selection is usually located on the shifter via a lever).

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Why does downshifting cause any unusual clutch wear? Is this information verifiable? What kind of downshifting? The clutch doesn't seem ot be doing any unusual job during a downshift. It slips, using friction to spin the engine up to faster rotation. Intuitively, this task is nothing compared to slipping to start the entire vehicle moving! And of course, the driver can learn to "match the revs".

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The advantages section considers manuals only against conventional automatic transmissions. CVT's should be considered too, since they fix some of the problems that automatics have and also have advantages of their own. CVT's use clutches rather than a torque converter, and so do away with the disadvantages of that device. Once the car is moving, there is no need to disengage the clutch unless it slows to a near-stalling speed, so these clutches should last a long time! Moreover, regardless of vehicle speed, engine can be run at the optimal RPM. So a CVT should get better fuel economy, and, in principle, better acceleration too. During hard acceleration, the CVT can slowly increase the gear ratio, while the engine stays fixed at its maximum power point.

That is the theory. However, CVT's do not quite deliver on their promise, at least the ones based on a metal V-belt spanning two pulleys. In spite of being in the ideal gear ratio, they have losses which compensate for that gain. See this paper: http://staff.bath.ac.uk/enssa/thesis.pdf Turns out that the belt has some surprising losses. For instance, as the belt goes around the pulley, it has to bend. This makes the V-shaped pieces move closer together on the inside and spread apart on the outside, which causes micro-slip against the pulley, generating heat. So that the belt doesn't actually slip as a whole, there has to be considerable friction on it. The force required to achieve that friction actually distorts the shape of the pulleys. This distortion of the pulley generates heat and represents a loss. Because of that distortion, the belt does not travel in a perfect semi-circular path around the pulleys, which results in more slip. So, a manual transmission is still your best bet for fuel economy. It matters more to have an efficient transmission than to be at some ideally perfect RPM.

Funny, because the Honda Jazz CVT has at worst 2% less fuel economy than the Honda Jazz w/manual transmission. (I heard that in many cases you get better economy with the CVT but I don't have any figures for that right now.) In fact, my 1983 BMW 520i manual lists the automatic transmission as having better fuel economy than the manual gearbox in city driving! That is presumably due to the gear selections in the automatic being better for low-speed acceleration, as well as the "slip" of the torque converter allowing the engine to sit in a more efficient RPM band for longer during acceleration. Therefore I think the claims that manual gearboxes are always more efficient than automatic are wrong. Instead of "5 to 15%" efficiency gain listed, I think "-1 to 15%" would be more correct, to represent that there are cases where automatic transmissions can do better.

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In a paragraph of the advantages section, I used feminine pronouns "she" and "her" to refer to a driver. This was deliberate. Some idiot edited that to "he" and "his".

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I am not opposed to merging my page close-ratio transmission into this one. I did not find your page before I set mine up. I went to the transmission page to look for the info before submitting it. I think there should be a more prominent link to your page from the transmission page, or at least more of our info included in the transmission page. Your thoughts?

I worked on the close-ratio transmission article some and I think there's enough to be said about it to keep it separate, especially since this article is pretty long already. I removed the merge notices. To get to this page from the transmission page, click on transmission (mechanics), and manual transmission is easy enough to find from there. TomTheHand 18:55, 16 January 2006 (UTC)

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I removed the controversial text about possible catalytic converter damage from push-starting, and the b.s. about elecronic engine management components not getting enough power from the alternator. If the fuel pump can pump, and the ignition coil can fire, surely some computers and whatnot can be powered up.

About that catalytic converter damage, it's nonsense. Let's look at this point by point:

• Suppose everything is working: ignition, fuel delivery. The alternator is generating current, so the coil can build up its field, which happens rapidly. Can the fuel injectors really spring into action before the ignition? Consider that the fuel pump, a mechanical device, has to spin up and build pressure. The ignition coil can energize very quickly: it has to, for high RPM operation.

• Suppose ignition isn't working at all (no plugs are firing) but fuel is delivered. Uburned fuel-air mixture is dumped into the exhaust. But what will ignite it? The machine is cold! And how is push starting different in this regard from cranking the starter motor?

• Suppose some plugs are not firing. Unburned fuel-air can be dumped into the exhaust and ignite, because the other cylinders are blowing out heat. This is the damaging situation for the catalytic converter. It's not attributed specifically to the push start; a regular start will do it.

So there is a good case to be made that this push-start-cat-damage is an urban myth, and as such, not suitable for an encyclopedic article. Manual drivers should not be afraid of push-starting their cars, especially when there is clear evidence that it's due to a drained battery that the car, which had been in working condition previously, isn't starting.

[edit] Ratio Manual/Automatic?

Does anyone have any info on the ratio of manual/automatic for cars in the US? This interests me as a lifetime manual driver, wondering what the potential sales market is for my manual car if I try to sell it!

Also, has the decline of manual stabilized here? Thanks! 207.13.211.199 22:25, 24 March 2006 (UTC)

[edit] Semi-manual Inaccuracy

In the Semi-manual subsection we have "Some very new transmissions (BMW's Sequential Manual Gearbox (SMG) and Audi's Direct-Shift Gearbox (DSG), for example) are conventional manual transmissions with a computerized control mechanism." There are two issues. Audi is a part of VAG, and the DSG is used by several car companies owned by VAG. The second issue is while the SMG is basically a computer controlled manual, the DSG or more accurately BorgWarner's DualTronic transmission is not "conventional". With two clutches DSG does't act like a normal manual transmission so it should definately be removed. --Pedantic79 05:35, 19 June 2006 (UTC)

[edit] Talk Cleanup

Can we cleanup this talk page? Many of the older conversations are difficult to follow with many people not signing their comments. And without subsections it's difficult to see what topics are being discussed. --Pedantic79 05:35, 19 June 2006 (UTC)

[edit] Really?

"It is sometimes possible to move a vehicle with a manual transmission just by putting it in gear and cranking the starter. This is useful in an emergency situation where the vehicle will not start, but must be immediately moved (from an intersection or railroad crossing, for example)."

I've heard this before but I cannot imagine that it would actually work, and if it did I imagine it would completely destroy the starter. Can anyone vouch for the truth of this statement? Mrestko 00:42, 23 June 2006 (UTC)

Sure is. In the OOOOllllllldddddd days, before the neutral and/or clutch interlocks, you could. No doubt extended use would fry the starter but.... I had a Corvair which used a clutch cable, which snapped at one point. For a few days, until the new cable came in, I just left it in first gear all the time and shut off the engine at every red light, then started it up again in gear when the light turned green. Worked fine. Gzuckier 13:17, 23 June 2006 (UTC)

Thus, would you say you have a legitimate reason to feel smug about having operated one of the first hybrid cars? KazKylheku 15:24, 23 June 2006 (UTC)

You know, I never thought of it that way..... Boy, I'm a pioneer! Gzuckier 17:30, 23 June 2006 (UTC)

There's ample proof of this technique in the film Ice-Cold in Alex Ian Dunster 10:32, 26 June 2006 (UTC)

It can work but it's certainly not good for the starter motor or the battery. I have accidentally started my Nissan Sunny while it's in gear and it does move a fair distance, while a friend of mine destroyed the starter motor on her Land Rover by trying to start it while in gear. I wouldn't recommend it unless you have no other choice. —The preceding unsigned comment was added by 84.92.243.251 (talk) 23:28, 30 March 2007 (UTC).

I've driven a manual car with a broken clutch before like this - stop in neutral (it's easy to change gear without a clutch when running) and when you want to set off, stop the engine, select first and then start the engine. Car will move while cranking uphil quite happily until the engine fires and then you are off.

I remember being on a Trailways bus when the driver told the passengers that the clutch had gone out and passengers would need to remain seated until the bus had come to a complete stop at the next station. We were on a freeway at the time, but had to deal with a few stoplights before the bus reached the station. Coming to the end of the exit, the bus had to make a right turn at a stop sign, but the driver was able to "slow and roll" through it. Fortunately, all the lights were green and the driver was able to get the bus into the parking lane at the station before killing the motor. Someone at the station tried to tell him he had to move the bus forward, but he told them he couldn't.

Are there still intercity buses with stick shifts around? There might be some in Canada and other countries, and charter companies might use them, but I don't think Greyhound or Trailways or any of the other bus companies use them very much in the U.S.71.131.206.40 00:56, 17 August 2006 (UTC)

[edit] One disadvantage is questionable

I'm from Brazil and I can say that people here hate automatic transmission. Automatic transmissions are found only in expensive and luxury cars. A person without special needs using a car with automatic transmission may be called lazy.

Manual transmissions require more driver interaction than automatic transmissions. In Brazil, people want interaction and this is considered an advantage. They call it feel the car... :200.218.226.26 19:28, 3 July 2006 (UTC)

Not only that, but why is the ability to engage in distracting activities an "advantage" of auto-boxes? Distracting activities cause road accidents.

• If you really weren't "lazy" then you wouldn't drive everywhere you go, fatso. And sometimes we need to engage in activities besides shifting because we're busy. Too bad we can't just drive around randomly for fun all day like you.

• Since when has something directly related to the operation of the car (i.e. driving) been distracting activity? :) Although I don't even think about shifting when driving, I would assume it makes the driver more aware of the fact he/she's not only listening to tunes in a metal box moving at 100 kph. Also, driving an automatic is hell during the winter when you try to get moving with minimal tyre wear (you simply have more feel with stick and clutch, possibly with a really expensive automatic as well). 84.231.109.82 11:15, 1 August 2006 (UTC)

[edit] Advantages (revisited)

I think there is a mistake in the "Advantages" section. It reads:

Driver control. Certain fuel-saving modes of operation simply do not occur in an automatic transmission vehicle, but are accessible to the manual transmission driver. For example, the manual-transmission vehicle can be accelerated gently, yet with a fully open throttle (accelerator pedal to the floor), by means of shifting early to a higher gear, keeping the engine RPM in a low power band.

As far as I understand, fuel consumption depends on the pressure given to the gas pedal and not on the engine revolutions (RPM). If you shift to a higher gear too early and press the pedal to the floor, the car will use more fuel than speeding the engine and then shifting gears. The feeling of shifting too early is discomforting: if you shift early you'll feel the engine doesn't have the "power" to speed up the car and you'll have to press the pedal to the floor. However, when you take the revolutions to the correct point and then shift, the engine will respond differently and you won't have to press the gas pedal too much.

I do agree with the fact that some fuel-saving "modes" are accessible to the manual transmission driver. But the problem is these modes are mostly incompatible with driving in the city: semaphores, traffic jams (your left foot gets tired of pressing the clutch), big changes in driving speeds and so on.

Congratulations, this is an excellent article.

--Hlasso 22:25, 19 July 2006 (UTC)

The gas pedal controls the restriction of air flow to the engine, not the amount of fuel delivered. The air flow is a function of the demand for air, which is very RPM dependent, and of throttling. The metering of fuel is a function of air flow. Fuel efficiency depends on how thoroughly fuel is combusted and how little of the resulting energy is wasted as heat. Engines operate most efficiently with unrestricted air flow (wide open throttle).

--KazKylheku 07:40, 20 July 2006 (UTC)

OK, but does it mean that when you press the gas pedal to the floor (thus completely opening the throttle) then the engine works more efficiently even when in the low rpms band? Hlasso 00:08, 22 July 2006 (UTC)

[edit] Right-of-Way in Europe

"Much more awareness of right-of-way is required, and a greater emphasis is placed on yielding right of way by slowing down rather than being required to come to an unconditional full stop regardless of whether an intersection is busy.

"Many intersections identify a right-of-way path through the crossing by a special diagram, and often legally require cars arriving by the non-right-of-way paths only to yield rather than come to a full stop. In some countries a yellow diamond indicates that this is a right-of-way road, and a gray diamond (or a yellow one with a black forward-slash across it) indicates the termination of right-of-way. In the UK and Ireland the termination of a right of way is indicated by 'Give Way' and 'Yield' respectively."

What does this discussion have to do with the advantages, real or imagined, of manual transmissions, or the preference for using them in Europe?

Perhaps nothing. So it's a good thing that the above text appears in the "Applications and Popularity" section, rather than in the "Advantages" section. :) --KazKylheku 07:16, 22 July 2006 (UTC)

I have no idea. Suggestion: remove it. --LimoWreck 23:44, 23 July 2006 (UTC)

[edit] Spelling Question

In the "Advantages" section, the word "manoeuver" is used several times. I'm not really sure about which way is the correct way to spell it. I'm pretty sure "maneuver" is standard American English and "manoeuvre" is standard British English, but I'm not sure if the spelling in the article is right. Could someone who knows change it? 67.55.199.6 23:46, 9 August 2006 (UTC)

Standard American English? Who cares. You spell it "maneuver" and the rest of the English speaking world spells it "manoeuver"

[edit] Informative article

Thanks i've always wondered how transmissions worked. Now I know. --Frantik 07:09, 15 August 2006 (UTC)

[edit] Automatic licence

As stated in the article, in the UK (and other countries such as Germany and Japan), drivers can take their driving test in an automatic, but the resulting licence will only entitle them to drive automatics in the future. If they want to drive a manual, they must re-take their test in a manual. Drivers who pass their driving test in a manual can obviously drive both.

My question: is this the case in the U.S.? Are drivers given the "choice" of an auto or manual license, and do they have to re-take a test in a manual in order to qualify to drive one? Also, would it be considered "odd" for someone in the U.S. wanting to learn to drive to want to learn in a manual car from the very beginning? --Tim1988 ^talk 14:59, 4 September 2006 (UTC)

As far as I know, the answers are No, No, and not necessarily. Gzuckier 16:16, 5 September 2006 (UTC)

[edit] Auto v Manual

I think everybody should try driving a manual!! it is so much fun and so much more rewarding that after you drive for a while you will simply get bored driving an auto., and you will WANT to drive a manual!! great feeling, this manual tranny.. and make sure you drive on a twisty, curvy road.. it's great to downshift right before a big curve.. altough i'm only 15, i have driven manually quite a bit (shh.. not supposed to get my license till i'm 16:)) and it is great fun..

[edit] Sliding mesh gearbox are still usual in trucks?

I think that a constant mesh geabox - with or without syncronizer - is common for a recent trucks. Sliding mesh gearbox are still usual in trucks?

"the rotation of all the sets of gears at once results in higher frictional losses" These sentences discribe disadvantages of the constant mesh gearbox to the sliding mesh gearbox , so these sentences are not suitable IMHO. 　

[edit] three on the tree,confusing

I thought that, reverse was... back,up. which matches the diagram, but not the text. which is it? CorvetteZ51 14:27, 10 October 2006 (UTC)

[edit] taxis

Contrary to what the article says, Taxis are pretty much universally equipped with automatic gearboxes here in Germany, and I bet it's the same in other European countries. Same with Police cars. About the "religious" aspects, these don't really make sense because both kinds of transmission are better in certain different situations. Busy city traffic with an AT is great, more concentration to read signs etc., stop & go is easier to handle too (and wears down a manual), while for a car that's primarily driven on the Autobahn, I'd take an MT version. Have driven both for a while.