MT Rev matching question
Three Wheelin'
Joined: Jan 2021
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Of course, as part of my experimenting of learning how to drive a stick shift, I have also tried not lifting the throttle as slammed through upshifts as fast as possible and yeah that can likely cause more wear on your clutch, transmission and potentially the engine. This was in the early 90s when I was driving a 240SX so it's not the like the engines revved very fast anyway. I cannot imagine doing any of the shennanigans I did with a modern day 500 hp manual transmission car.
Three Wheelin'
Joined: Jan 2021
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- Gear shifts should generally be sequential, unless you have the skill to rev match beyond a single ratio. Skip up shifting is fine if you let the rpms drop a bit more before putting in the gear, a slow shift. Rev matches beyond one gear I personally recommend double clutching but I wouldn’t force that idea. Though the synchros can probably handle it, you may find some resistance in putting the stick into gear if you go beyond one or two ratios.
Advanced
Joined: May 2024
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From: CA
Modern manual transmission cars - and I mean pretty much all manual cars since the 1980s, do not have any issues when downshifting multiple gears as long as you rev match appropriately. I have never driven a manual transmission that required double clutching to get into gear. I could pretty much downshift multiple gears all the way down to 1st gear before the car stopped in every manual car I've ever owned since 1987 because they all had dual cone synchros, etc. I think the need to double clutch and cars that were hard to get into gear were cars built in the 60s and earlier. The oldest manual car I've driven was like a late 1970s Toyota Celica and it shifted though the gears up and down without any issues or need to double clutch. As long as I rev matched I never had any issue sliding the shifter into the gate. In fact, for almost all of these cars I could just pull or push on the shifter with clutch fully engaged and as the revs dropped to the correct RPM, the shift lever would slide into the lower gear without any crunchy noises at all. I'm sure it probably placed add'tl wear on the transmission but yeah, this was when I was younger and just experimenting and trying different things from what others showed and taught me. I never even heard about "double clutching" until I started reading the internet in the early/mid 90s b/c it was never something that was ever needed or was ever taught.
Hence why I said double clutching is optional, it was my preference because it had tangible benefit. In my e90 335i the stick definitely had more resistance between large ratio shifts at high RPM compared to low rpm. Even an UPSHIFT from 1>2 at redline would occasionally give me trouble. It took a lot of force and a slight delay for the gear to go in at that rpm. A shift from 5->2 certainly encountered more resistance than 5->4. A double clutch eliminates this resistance. Sure, it will work without issue but the double clutch honestly reduces the resistance and makes these shifts easier than not doing it. Sometimes you get that magic double clutched downshift where you rev matched so perfectly that not even the synchros put up any resistance. The stick just slides into gear. It’s not necessary but nothing about manual is necessary either, hence why the art of it all is intrinsically worthy of pursuit.
Last edited by wujax; Jul 8, 2024 at 08:12 PM.
Instructor
Joined: Aug 2020
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Double clutching is for tractors or non synchro gear boxes
I can't ever imaging driving a 911 where you push the clutch to disengage the gear, release the clutch in neutral to spin up the shafts, then depress the clutch agin to select the next gear
Its not the same as rev matching or heal-and-toe
I can't ever imaging driving a 911 where you push the clutch to disengage the gear, release the clutch in neutral to spin up the shafts, then depress the clutch agin to select the next gear
Its not the same as rev matching or heal-and-toe
Advanced
Joined: May 2024
Posts: 96
Likes: 73
From: CA
Double clutching is for tractors or non synchro gear boxes
I can't ever imaging driving a 911 where you push the clutch to disengage the gear, release the clutch in neutral to spin up the shafts, then depress the clutch agin to select the next gear
Its not the same as rev matching or heal-and-toe
I can't ever imaging driving a 911 where you push the clutch to disengage the gear, release the clutch in neutral to spin up the shafts, then depress the clutch agin to select the next gear
Its not the same as rev matching or heal-and-toe
look you don’t have to if you don’t want to. I’m just trying to convey that when you do it and hit it just right, it’s pretty awesome.
Instructor
Joined: Aug 2020
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Double-clutching (also called double de-clutching outside of the United States) is a method of shifting gears used primarily for vehicles with an unsynchronized manual transmission, such as commercial trucks and specialty vehicles. While double clutching[1] is not necessary in a vehicle that has a synchronized manual transmission
The double-clutching technique involves the following steps:
- The accelerator (throttle) is released, the clutch pedal is pressed and the gearbox is shifted into neutral.
- The clutch pedal is then released, and the driver matches the engine speed to the gear speed either using the throttle (accelerator) (when changing to a lower gear) or waiting for the engine speed to decrease (when changing to a higher gear) to a level suitable for shifting into the next gear.
- At the moment when the revs between the input shaft (i.e. engine revs) and gear are closely matched, the driver then presses the clutch again, shifts into the next gear, and releases the clutch. The result should be a smooth gear change.
Advanced
Joined: May 2024
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From: CA
