Another thread (which I rudely hijacked) got me wondering how many people know how to downshift their manual transmission cars properly.
Which of the following is the better* way to downshift a manual transmission car?
METHOD A
Clutch pedal in.
Move gearshift to appropriate gear.
Clutch pedal out.
METHOD B)
Clutch pedal in.
Move gearshift to appropriate gear.
Blip throttle so that engine is turning at appropriate speed for selected gear.
Clutch pedal out, quickly.
One of these methods results in wear on your clutch, disturbance to your passengers, stress to your drivetrain, and the risk of losing control of your car in slippery conditions. The other does not result in any of these things, including any wear on your clutch.
Methode B still results in excessive wear on synchnizers in transmission.
Clutch pedal in. Or just manipulate throttle to unload engine… neither pulling and braking.
Move gearshift to neutral.
3)Cluch out if pressed in step 1.
Blip throttle so that engine is turning at appropriate speed for soon to be selected gear.
5)Clutch in. (optional if your REALLY good, meaning you probably drive for a living)
6)Move shifter to appropriate gear.
7)Clutch pedal out, quickly. (not needed if step 5 skipped)
Methode B as discribed is appropriate for a ratchet shifter, as found on nearly any motorcycle, no good way to catch neutral between gears.
I must admit I had heard that method B was not considered necessary any more from several sources but non of them would I consider completely authorative on the question. I may even do something like B without recognising the fact, after all everyone who drives manual for some time gets used to changing gear in such a way to minimise disscomfort and lack of smoothness of the gear change.
I have no clue what this means. The only reason I would do anything to the throttle while downshifting is if I was doing so in expectation of getting more power to get up the hill, or pass somebody. But normally I downshift because the engine is turning at an appropriate speed for the gear I’m going to or because I want to slow down.
Kevbo, I intentionally said better, not best. Read the last line of my post. And shush!
I don’t want to derail the thread with discussions about Method C). Or D), for that matter, which has the initials HT.
Double-clutching is what **Kevbo described.
Downshifting incorrectly disturbs your passengers because the car jerks / slows down when you use the clutch to speed the engine up. If you compensate by engaging the clutch veerrryyy sllllooowwwlllly, you might be able to mask the effect by extending the duration, but then you’re just putting even more wear on the clutch.
Absolute, I guess if one has to choice, then Method B is better, because you’re dragging the clutch less. But not double-clutching means that you aren’t actually matching the revs of the tranny and the engine, and your synchros suffer, as Kevbo said.
Method A. I guess that you could label both the in and out of the clutch as “quick.” I don’t ride the clutch. I’ve been driving manuals as a daily drivers since 1992 (and off and on since 1987).
This makes no sense. The whole point of shifting is to change the speed the engine is turning at. 30 mph in 2nd gear means your engine is turning around 3000 RPM. In 3rd, perhaps around 1800. If you are doing 30 mph in 3rd, the engine is most definitely not turning at the right speed for 2nd, and when you downshift you have to deal with that. The right way to do it is with the throttle, the wrong way is with the clutch.
Double-clutching is not necessary to get a smooth transition, or avoid wear on the clutch. I’ve found that most people have enough trouble accepting the validity of Method B, that bringing double-clutching into the equation just complicates things. Especially since a lot of people (perhaps correctly) think that double-clutching is unnecessary on modern cars, confuse double-clutching with Method B, and then decide Method B is unecessary.
Bippy, Kevbo’s method is what some people say is unecessary. However, Method B is definitely necessary if you don’t want to be replacing your clutch twice as often as you should.
I thought the whole point of a modern synchromesh gear system was that you didn’t have to worry about this stuff. In other words, “don’t ride the clutch and you’ll be fine.”
Looks like UK driving instructors are in cahoots with clutch replacement centers, since slowly releasing the clutch is what is I beleive generally taught.
How rapidly do you raise the clutch when you ‘blip’ is it almost as fast as just taking your foot straight off the pedal?
Yup.
And they must be in cahoots, because dragging your clutch is BAD. It should be treated almost as an on/off switch, and the transition from “on the floor” to “foot off” should be as rapid as possible for your coordination level.
That takes care of the absolute requirement to double-clutch. It used to be the case that, if you didn’t double-clutch, you would grind gears.
Now, you don’t have to double-clutch. You don’t have to rev-match either, you can just lift off the pedal like Unregistered Bull and let the clutch bang the engine up to the correct speed.
But rev-matching is better, safer, cheaper, and results in a more pleasant driving experience for you and your passengers. You can still double-clutch in modern cars, but whether the rest of the car will last long enough for you to notice how well your synchros have held up is debatable.
However, if you keep your car long enough to have to replace a clutch, you will definitely notice a difference in its longevity if you rev-match.
Essentially, yes. If you wait too long, the engine RPMs will drop too low.
Well gosh, I was deffinately taught (and I had two different professional instructors over time since the first one was a psycho, and so I changed instructor before I took the UK test) to raise the clutch slowly so that there wasn’t a sudden jolt. Raising rapidly until you start to feel the power connect and then very gently ease up until there is full connection. Maybe taking up to two seconds to complete.
Not that I have any doubts of your knowledge or sincerity over these facts, but do you have any info or cites as to how much difference this would make over clutch lifespan? I have never has a clutch fail on me, but then again I haven’t had a car for more than five years yet.
Are there any general guidelines to follow to determine what the appropriate speed of the engine would be for a given situation, or is it something that varies too much from car to car and needs to be learned by experience? I generally attempt to downshift “correctly” (Method B), but I don’t always feel like I know what I’m doing.
