I've been driving many cars with tired synchro rings over the years and i quite enjoy how smoother the shifts are when double clutching some of them. With some transmissions it is also possible to float gears but most automotive synchronized transmission really don't like that punishment. I have noticed that for over a year, most of the time my technique is: float out of gear then clutch into next gear. It's a bit like an hybrid method that makes the shifts buttery smooth while avoiding to press the clutch twice. It's a bit weird but i was wondering if anyone else is doing something similar here.
Manual transmission weird shifting technique
- Thread starter OM605
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I think I understand what you mean by float, push the shifter into neutral without using the clutch by unloading the drivetrain? Then clutch to the next gear.
Not helpful to the syncro's. You may feel a little 'bite' as you slide it out of gear. That's the (typically brass) syncro breaking free and wearing. Something that does not happen during a normal shift out of gear.
Your very best bet for longevity is to drive a manual normally, shifting smoothly, firmly and not so quickly as to severely load the parts, not so slowly as to let the syncro's continue to wear as revs change.
Not helpful to the syncro's. You may feel a little 'bite' as you slide it out of gear. That's the (typically brass) syncro breaking free and wearing. Something that does not happen during a normal shift out of gear.
Your very best bet for longevity is to drive a manual normally, shifting smoothly, firmly and not so quickly as to severely load the parts, not so slowly as to let the syncro's continue to wear as revs change.
I've found with every manual transmission car I've owned, it was possible to float gears with careful operation. Getting out of a gear and into the next I've found easy; just have to time it right if you want a seamless engagement. It's the downshift where you have to bring revs up that is the challenge, and I'd never gotten good enough where I thought the effort was worth the gear clashing when you didn't get it just right. And people behind you tend to get PO-ed when you all the sudden stop accelerating.
On medium duty trucks I found it quite easy both ways, but then everyone behind you expects to you be accelerating slowly.
To me it's easier to just operate the manual as it was intended and let the syncros do the work. If I am doing a drastic downward gear change, I might make an effort to rev match before I begin to engage the lower gear.
On medium duty trucks I found it quite easy both ways, but then everyone behind you expects to you be accelerating slowly.
To me it's easier to just operate the manual as it was intended and let the syncros do the work. If I am doing a drastic downward gear change, I might make an effort to rev match before I begin to engage the lower gear.
Thanks for this. I didn’t know it was harmful to the synchros. I’ll shift normally.
It's a good way to shift quickly which is a life skill that comes in handy. Put a couple pounds of force towards neutral, the stick will head that way when the load from the engine is removed. That happens by either letting off the gas or starting to declutch.
Well, cool, you're halfway declutched and getting more so every millisecond, and the stick is on the move, to the next gear up, more than likely. So enter the next gear, dump the clutch, and get back on the gas. It's not great for things, but it's not that bad, and sometimes in life you've gotta get out of dodge.
Second gear synchro goes out first, anyway, from people slowing for corners and not double-clutching. The rest of the synchros go to the junkyard in fine shape. Feel free to use a little bit of 'em.
Well, cool, you're halfway declutched and getting more so every millisecond, and the stick is on the move, to the next gear up, more than likely. So enter the next gear, dump the clutch, and get back on the gas. It's not great for things, but it's not that bad, and sometimes in life you've gotta get out of dodge.
Second gear synchro goes out first, anyway, from people slowing for corners and not double-clutching. The rest of the synchros go to the junkyard in fine shape. Feel free to use a little bit of 'em.
The 1995 Corvette was easy to control the RPM and glide in and out of gears, did it regularly and never had an issue. But also the ZF S6-40 transmission is known as a robust gearbox, very tough and well-made. Can't say if other units would have held up so well.
Second or third are the usual synchro failures in my experience. You can feel when you're working them hard as there's resistance to go into gear, and you can often hear the gears spinning up. Most people don't notice and just attempt to jam the shifter into gear on a downshift.
How does pressing the clutch twice make the shift any smoother?
On a vehicle with worn synchros, it's almost a necessity to rev match to the chosen gear, which double clutching makes easier. I assume that's what he's talking about.
If not, I struggle to see how double clutching makes a shift smoother with a working synchro transmission.
Having spent some time driving an unsynchronized delivery van, I’m happy to let the synchronizers do their job as designed .
You let off the clutch in neutral and goose the gas, which spins up the "far end" of the transmission to match the "near end." Then you use the clutch a second time and put the two together.
Why can't you just goose the gas when the clutch is pressed the first time?
Because with the clutch depressed, pressing the gas is only changing engine speed and nothing in the transmission.
The output side of the transmission is spinning by the driven wheels, always spinning while the vehicle is in motion. The input side connected to the clutch/engine is essentially coming to rest with the clutch engaged. By letting the clutch out in neutral, it spins the input shaft side of transmission to engine speed. You can then feather the gas pedal to spin it up to a speed that matches the desired gear vs. output shaft speed (driven wheels) before shifting gears, making gear changes easier on the synchros. Or in the case of failed synchros, it's all you can do to make a gear change possible without a lot of grinding. Hope this makes sense.
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