I used to do it on company cars, when the mood took me. It's handy to know just in case the clutch cable breaks. As is getting the car moving on the starter while in first gear.
However I'm sure these things aren't good for the car.
Up changes are pretty easy, just back off the gas and change gear. It's allegedly a little faster than using the clutch.
Down changes require more practice - push the lever into neutral at the same time as backing off the gas, then blip the gas (the amount of blip is the skilful bit) and pop the lever into the lower gear. Prob best to practice on a hire car.
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Isn't that almost like double declutching?
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Isn't that almost like double declutching?
Similar principle - you are trying to get all the cogs to match speed so they don't graunch as it goes into gear.
To go up, just accelerate gently, as you get about mid way in the rev range apply slight preassure on the gear lever in the direction of the next gear, as you then ease off the gas you will feel the gear stick just fall out of gear, as it does keep it moving in a smooth motion over to the next gear up and it should just drop in with out any fuss.
To go down, ease off the gas whilst applying slight preassure on gear lever, it will drop into neutral, as it does apply gas and ease towards new gear, if you have applied the right ammount of gas it will drop straight in - if not then you will play the "Tublar Bells" for a while ;o)
Once you can do it it is easy and a very lazy way of driving, I cut my teeth driving constant mesh boxes in trucks - similar principles.
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Changing up not using a clutch is too easy to be boring.
When bored I practise down changes and braking at the same time.
Foot on the side of the brake pedal (gently), brush the side of the foot against the gas pedal increasing the revs in a blip, the gear lever slips out as the revs rise and the speed drops and slips into the lower gear as the revs rise and fall to match the new speed.
Not been able to block change down like that tho~!
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TourVanMan TM < Ex RF >
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Foot on the side of the brake pedal (gently), brush the side of the foot against the gas pedal increasing the revs in a blip,
You can't do this in many car now - pressing the brake pedal tells the ECU to stop the supply of fuel, so you can't brake and blip the throttle at the same time.
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Very easy in some cars if you take your time, very difficult in others. It isn't for nothing that a gearbox without synchromesh is caqlled a 'crash' box. That said, in some cars with very powerful synchromesh it's quite easy. All I can say is, unless you don't give a damn, don't try it in say a front-wheel drive Alfa. Basically you jerk the lever into neutral, synchronise engine and road speed for the gear you're changing into, either by lifting off or blipping the throttle (not blipping but doing it deliberately if you know what's good for you), and bang the lever into the right gear at the right moment. Like anything else you get better at it but some cars just don't have the bottom for it. With an early 60s Ford baulk ring synchromesh box you could just lean on the gear lever and when the speeds were right it would drop in. In some cars you can make a truly horrid noise and even do damage. Don't do it unless you really need to.
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On most motorbikes it's a doddle to change gear without using the clutch. Motorcrossers / trail (or is it trial?) riders also don't bother with the clutch whilst racing as it's quicker to change gear without.
Getting back to cars, when I used to drive hire cars a lot, the best ever gearbox I found to change gear without using the clutch was the 1.8LX Sierras.
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It's not the same as double declutching, because as its name implies, that is using the clutch twice, instead of not at all.
You have to visualise what is going on in the gearbox.
There are 2 different shafts with associated cogs:
1) is the input shaft, connected to the lay-shaft
2) is the output shaft.
The output shaft always turns at the a speed which is locked to the road speed. The input shaft rotates at engine speed, but only when the clutch is engaged. Changing gear requires a new set of gears to enmesh, which means the layshaft, and therefore input shaft, have to be adjusted to the new appropriate speed.
With the clutch disengaged, the input shaft/layshaft can run freely, so it will slow down by itself. That is what needs to happen when you change up, which is why upward changes are so easy, with or without a clutch.
But a down change requires the layshaft to speed up, and that can only happen by the driver blipping the throttle while the clutch is engaged. If he then declutches again, the layshaft keeps spinning, but only has its own momentum. The consequences of missjudging the speed are fairly small. But in a clutchless change, the whole spinning momentum of the engine is applied to the point where the teeth mesh, so if you get it wrong, potentially the teeth can be ripped off.
Of course with syncromesh any mismatch of layshaft and output shaft doesn't normally matter, as long as it is only the layshaft's own momentum, not with the engine coupled as well.
Long reliance on syncromesh to do this part of the job has probably made most drivers not very well atuned to the subtleties of gearbox shaft speeds, which it is why clutchless changes are best left to cars you don't cxare about, or emergencies.
There is (or was) a final variation, which I think was called a racing (down)change. In this the clutch was partially disengaged, but the foot kept hard on the accelerator (foot twisted sideways if necessary for heel and toe). The engine tried to speed up, and you slammed the gear through just as the speed had risen enough to match the gears. That way power was maintained throughout the change. Needless to say, it was even tougher on the box than a clutchless change.
In a leisurely clutchless change you can usually "feel" the teeth about to engage by the oil drag, so can adjust the speed a bit if necessary.
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Getting back to cars, when I used to drive hire cars a lot, the best ever gearbox I found to change gear without using the clutch was the 1.8LX Sierras.
Something in that: in Sierras and my old Chevette, clutchless gear changing was dead easy. In a Fiesta, it wasn't worth it. Is it easier in a rear wheel drive, perhaps because it's a more direct change?
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I remember doing this years ago (21 to be exact) when I was an apprentice mechanic. We used to collect the cars from whereever it was, usually the customers house & tow it away via towrope. Once out of sight from the owner we unhooked & I'd drive the thing back. Sometimes this was through rush hour traffic.
I mastered it well but it was always a pain if you had to come to a complete stop - turn off engine, put it in first and turn the engine over again until it fired up. Some cars were better than others but as this was a VW Audi dealership most of these seemed ok.
No longer in the trade now but I bet it still goes on.
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In my youth, I used to have an E28 BMW 5er, it was a doddle in this with Getrag gearbox, I also tried it on various company cars, but it felt like it was grinding the gears and certainly didn't satisfyingly 'pop' in like with the BMW. The FWD cars seemed as though the cogs were smaller and more likely to not line up, but the BMW felt like big cogs and once the revs were correct a little pressure on the lever, and the lever would just gently pop into gear effortlessly. I drive automatics these days.
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Easiest gearbox I ever had was a Hillman Imp - just didn't bother with the clutch once under way.
Of course, there were lots of other things to go wrong...
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Wouldn't the clutchless changing see off the gearbox in double quick time?
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Mike,
cooling system
electrics
cooling system
front tyre camber
cooling system
fuel gauge
cooling system
drivers seat falling apart
cooling system
?
JH
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