Clutchless Gearchanges

[crr003]

....Last time I needed to use this technique was a couple of Novembers ago, after the garage had done some work on the car the previous day and I woke up to find the clutch wouldn't disengage
.........

Braver man than me - I'd be calling AA/RAC/Green Flag or whoever I was joined up with!

[Gareth]

....Last time I needed to use this technique was a couple of Novembers ago, after the garage had done some work on the car the previous day and I woke up to find the clutch wouldn't disengage
.........

Braver man than me - I'd be calling AA/RAC/Green Flag or whoever I was joined up with!

It helps to have practiced a bit beforehand. Mind you, I'm not particularly good at this, just adequate when I need to be.

One thing to remember is not to rush the gear changes. The anxiety of having to do something you don't do all the time generally makes one a little bit too eager when trying to select the next gear.

I suppose in some way it isn't that far removed from driving an automatic smoothly - if you remember to allow time for the gear change to take place, it is often easier to get good changes.

[James]

Ive been doing this tonight. I will leave it to your imagination what vehicle I have been using.

I have no problems on the doenchange, a few are a bit jolty but generally very smooth. Practice makes perfect. Can't do it on an upshift though?

[Gareth]

Can't do it on an upshift though?

I think the main point is to be unhurried, and listening to the engine often helps. If the engine and road speeds match, it will go in, so you must be getting the engine speed slightly wrong.

An easier way to test whether you really can match engine speed to road speed is to look at the rev counter when you engage a gear using a normal gear change. If the needle is completely steady as you lift the clutch, then you should be able to do a clutchless change. More often the people will find the needle moves as clutch drag synchronises the engine speed to the road speed, (unless you're miles out, in which case it is the other way round and the gear change feels jerky).

[James]

Going down seems OK but up just seems impossible, I mean, you could change up a gear between 2k or 8k of revs, it doesnt really matter, so what does the car want you to do? Does it have a preferred time to change up a gear? Are you supposed to take it out of gear and then sustain revs on an upchange? If so this seems time consuming and not quite right.

[Gareth]

Does it have a preferred time to change up a gear? Are you supposed to take it out of gear and then sustain revs on an upchange? If so this seems time consuming and not quite right.

The only thing to think about is matching engine revs to road speed for the chosen gear, so applying that, as you come out of the lower gear, you need to let the revs drop, then at the point they match the road speed for the higher gear, engage the gear.

What makes this tricky is (a) being too hasty and not letting the revs drop enough, or (b) taking too long and letting the revs drop too far. Of course once you know how fast the engine needs to be, both of these are trivial to overcome but the theory is easier than the practice

The easiest way to practice is with light acceleration in the lower gear up to the slightly beyond the point where it is reasonable to engage the next higher gear. For some reason, all gear changes tend to be trickier at higher revs, but perhaps it just requires more precision.

As an aside, my wife first came across this when she was taking a car back from an MOT station to the garage where she was working. She had come to a stop at a busy roundabout for an M25 junction, but was unable to get it in gear again. A police car turned up, and one of the officers got in and found that it was possible to get it in gear when the engine wasn't running, so drove it clutchless across the roundabout and on to the nearest lay-by. My wife was very impressed!

[rlmr]

Does it have a preferred time to change up a gear? Are you supposed to take it out of gear and then sustain revs on an upchange? If so this seems time consuming and not quite right.

I found the "company" MkI Ford Escort and Transits back in the mid 70's, were very good for practising on the night-shift

Actually Ford have always made excellent gearboxes, most suited to clutchless changes... my kit car had a Ford Gearbox and it was quite easy to change without the clutch.

We were taught to double de-clutch and match the engine rev's at all times, so as a result just omitting the clutch action but still matching the engine / gear speeds comes naturally. I think the Ford synchromesh is probably very good and that makes the clutchless change a bit easier in these vehicles.

In brief when changing up a gear you have to power off slightly to allow the gear lever to be moved... slip into neutral and control the engine speed so it falls, but not too far and exert a pressure on the gear lever and the lever will slip into the lower gear when the rev's are correct (you will be able to judge this with practise, but initially just a slight pressure and the synchromesh will take over. With the down change again you do not want to by powering on... on the level you need to apply just enough accelerator to keep the car moving at a constant speed... then take the lever in to neutral... with the load off the engine the engine rev's will rise... generally if you have got the accelerator setting correct for the level (no increase or decrease in vehicle speed) this rise in engine speed will be spot on for 1 gear lower... then its just a case of a slight pressure on the lever and it will slip into gear. Exactly the same theory as deep double de-clutch balanced rev changes... but without the clutch.

There is really no need for this these day unless you have a mechanical fault and the clutch will not disengage, but the theory about matching engine / gear speeds s still sound and will assist a normal gear change.

As for the poll: I regularly use clutchless changes on my motorcycle and I still practise in the car at times... in the 44 tonner its par for the course with the Eaton twin splitter gearbox fitted to the ERF's, but the Volvo's are auto boxes with an electronically controlled mechanical clutch.

regards,

Rennie

[James]

I found the "company" MkI Ford Escort and Transits back in the mid 70's, were very good for practising on the night-shift

Actually Ford have always made excellent gearboxes, most suited to clutchless changes... my kit car had a Ford Gearbox and it was quite easy to change without the clutch.

[/b]