Clutchless gear changes.
Discussion
But how wrong is too wrong?
) using clutchless changes, but i'd never do it to my own car. It's far too hard to do, but in the van i get enough time to think about it all seeing as it's about as slow as a snail with a cold.focusonme said:
Someone care to explain? I've always thought if you change gear without a clutch it'll just destroy various bits of the car?
You have to match the engine revs to the road speed of the wheels pretty much exactly - too high or low and the gears won't mesh, but will be spinning at different speeds - and hence the possibility of knocking bits off teeth and / or synchromesh dogwheels.
If you get it right, do it gently by "touch" then it can be done - like others have said, I have driven home this way after losing the clutch - the first time almost 30 years ago in a Ford Corsair, which lost its clutch arm, slave cylinder and all its clutch fluid on the edge of Edinburgh - my clutchless drive was going fine until I reached the Forth Road Bridge and had to stop to hand over my toll money... starting again was a laugh!
I also used to do it when I was an IAM observer doing demo drives with 3 newbies in the car - just as a party trick!
Yes. It's the same speed-matching skill as required for a smooth clutched gearchange, only more precision is needed. Acquiring the necessary precision isn't too hard as you get good feedback from the feel of the gear lever - if it resists being moved you're not quite there, get it spot on and it should just slip in/out easily (fnarr fnarr).
I used to do it occasionally just for the crack in my Morris Minor (which makes it very easy with its lovely gearchange), and the practice stood me in good stead on the day the clutch linkage broke on the way to work. Rush hour, so I couldn't avoid the occasional stop - but a Moggy has such a low first gear it's not much of a problem starting it in first
It's even easier on a bike. The gearbox on a bike has a primary reduction gear on the input so it's turning over a lot slower than a car one; the dogs are big and chunky and have a lot of clearance; the gears are small so the rotating inertia is low; the ratios are usually close so the speed difference is not large; and the engine is extremely responsive and can change revs rapidly. It's common on racing bikes to have a switch which cuts the ignition when you move the gear pedal to change up, so you can do full-throttle clutchless upshifts and save valuable milliseconds.
I used to do it occasionally just for the crack in my Morris Minor (which makes it very easy with its lovely gearchange), and the practice stood me in good stead on the day the clutch linkage broke on the way to work. Rush hour, so I couldn't avoid the occasional stop - but a Moggy has such a low first gear it's not much of a problem starting it in first
It's even easier on a bike. The gearbox on a bike has a primary reduction gear on the input so it's turning over a lot slower than a car one; the dogs are big and chunky and have a lot of clearance; the gears are small so the rotating inertia is low; the ratios are usually close so the speed difference is not large; and the engine is extremely responsive and can change revs rapidly. It's common on racing bikes to have a switch which cuts the ignition when you move the gear pedal to change up, so you can do full-throttle clutchless upshifts and save valuable milliseconds.
I do it sometimes. As others have said, if you apply a bit of finesse you can do it without expensive noises emanating from the gearbox. Much easier on upshifts than downshifts.
I used to have an Alfa which was brilliant at it - you could go up and down the box in complete silence and smoothness and only ever use the clutch to move away from standstill.
I used to have an Alfa which was brilliant at it - you could go up and down the box in complete silence and smoothness and only ever use the clutch to move away from standstill.
Used to do it all the time with an old Sierra Sapphire - even from lights sometimes hooking fiorst without the clutch. That came about after it suffered recurring 'clutch' problems during its life and, combined with a regular tendency for the engine to oscillate betwen 1k and 4k revs at tickover, could be more than a little interesting to drive in towns when it decided to have a double bad day. It was a company car so some days I really didn't care what happened to it.
In the end I realised that the clutch pressure plate was faulty - probably from new - but 2 clutch changes, one under warranty - and finally a recon box (not required) convinced me that very very few garages really know what they are doing. The pressure plate had never been changed despite the continuing problems. The engine oscillation turned out to be a rather short and badly run and badly seated vacuum pipe which I suspect had been bodged during a service in its early life.
Anyway, clutchless changes were a cinch once those problems were resolved.
More recent cars tend to be trickier. Mrs. LongQ's Citroen has some engine management stuff that always makes the revs rise a touch on de-clutch. Possibly useful on a down change but very bad news on an up change. Does not encourage me at all.
Anyway, since my left foot had got used to resting in the Sierra I decided it needed to work more - so I have bought Automatics since the Sapphire went and use left foot braking to get some exercise!
I recall my father telling me that he was taught the clutchless method driving military trucks during WW2. With slow running engines you could time the changes and 'count' them to perfection on the upchanges.
In the end I realised that the clutch pressure plate was faulty - probably from new - but 2 clutch changes, one under warranty - and finally a recon box (not required) convinced me that very very few garages really know what they are doing. The pressure plate had never been changed despite the continuing problems. The engine oscillation turned out to be a rather short and badly run and badly seated vacuum pipe which I suspect had been bodged during a service in its early life.
Anyway, clutchless changes were a cinch once those problems were resolved.
More recent cars tend to be trickier. Mrs. LongQ's Citroen has some engine management stuff that always makes the revs rise a touch on de-clutch. Possibly useful on a down change but very bad news on an up change. Does not encourage me at all.
Anyway, since my left foot had got used to resting in the Sierra I decided it needed to work more - so I have bought Automatics since the Sapphire went and use left foot braking to get some exercise!
I recall my father telling me that he was taught the clutchless method driving military trucks during WW2. With slow running engines you could time the changes and 'count' them to perfection on the upchanges.
It shouldn't cause too much of a problem to the synchros - their job is simply to help match the next cog's speed and allow the dogs to engage. You're much more likely to damage them with a low transmission oil level than clutchless gearchanges.
But I've got two very worn selector forks to show what happens if you rest your hand on the gearlever! I bought an old Subaru with a broken gearbox, which was obviously caused by a lazy driver. Eventually one face of the forks wore away so much they were unable to move the hub far enough to overcome the detent and engage the next gear.
For the record, the easiest car I ever drove for clutchless gearchanges was also a Sierra Sapphire (horrible, horrible car), closely followed by my 309GTi - which also came in handy when the clutch cable snapped! It's nigh on impossible to get right on my Lancia though - I guess the 4WD hardware mated to a laggy turbocharged engine doesn't help much...
But I've got two very worn selector forks to show what happens if you rest your hand on the gearlever! I bought an old Subaru with a broken gearbox, which was obviously caused by a lazy driver. Eventually one face of the forks wore away so much they were unable to move the hub far enough to overcome the detent and engage the next gear.
For the record, the easiest car I ever drove for clutchless gearchanges was also a Sierra Sapphire (horrible, horrible car), closely followed by my 309GTi - which also came in handy when the clutch cable snapped! It's nigh on impossible to get right on my Lancia though - I guess the 4WD hardware mated to a laggy turbocharged engine doesn't help much...
The trick is to go from one gear to the next whilst the weight is of all the cogs in the box. As you accelarate, the one cog is pushing another around.
Then, when you lift off, the drive cog on the pinion shaft slows and is pushed round, or kept at the same speed as the cog on the layshaft.
So there is a split second as you lift off the throttle that neither cog/ratio is pushing the other, i.e there is no weight on either cog.
This is the time when you need to whip it into the next gear. You've gotta be quick though. Once you have missed the chance and engine braking kicks in you have lost your chance.
Thats why they invented the synchromesh - make the most of the invention and give the clutch a little dab.
I use an F3 car with no synchros and you can change pretty damn quick with a little clutch dab.
I certainly dont think you need to do it on the road.
Also, if you knacker the dogs in a racing hewland box you just change them in about an hour max, but yo cant do that on you mondeo etc.
>> Edited by RossyVR6 on Thursday 8th September 23:48
Then, when you lift off, the drive cog on the pinion shaft slows and is pushed round, or kept at the same speed as the cog on the layshaft.
So there is a split second as you lift off the throttle that neither cog/ratio is pushing the other, i.e there is no weight on either cog.
This is the time when you need to whip it into the next gear. You've gotta be quick though. Once you have missed the chance and engine braking kicks in you have lost your chance.
Thats why they invented the synchromesh - make the most of the invention and give the clutch a little dab.
I use an F3 car with no synchros and you can change pretty damn quick with a little clutch dab.
I certainly dont think you need to do it on the road.
Also, if you knacker the dogs in a racing hewland box you just change them in about an hour max, but yo cant do that on you mondeo etc.
>> Edited by RossyVR6 on Thursday 8th September 23:48
GreenV8S said:
There was a time when I got carried away with this and started doing clutchless heel-n-toe gear changes. There's rather a knack to it, but it's very satisfying when it works. And you never know when you might find yourself in a race situation with a broken left leg ...
I thought that is why you have the Granada, although a racing situation in that would be rare!
GreenV8S said:
There was a time when I got carried away with this and started doing clutchless heel-n-toe gear changes. There's rather a knack to it, but it's very satisfying when it works. And you never know when you might find yourself in a race situation with a broken left leg ...
I used to do this in my old Astra, It was a bit of intrest for the slog home.
Amazing what you can do with one leg
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