ADUK Archive

Hi,
When driving my car for the last couple of weeks I've been trying to practise smooth gear changing. I'm starting to get the hang of smooth down changes, and with practise I'm starting to hit the spot each time.

I'm struggling however, with smooth up changes in the lower gears. Particularly 1st, to 2nd, and 2nd to 3rd. It's either quite jerky, or I have to wait too long for the revs to drop enough to make the change smooth that the car slows down too much and I fail to make enough progress and smooth acceleration.

Please could anyone help and point out what I'm doing wrong and what I need to look at and work on to improve smooth acceleration and up changes? Also can you get smooth up changes even when going up a steep hill when you have to rev higher before changes?

Thanks

Richard

It depends what you want to prioritize.

If you want to minimize clutch wear, then the only thing you can do is make sure you get completely off the accelerator during the middle of the shift and just wait for the revs to drop far enough before re-engagement. You could also change the flywheel or look for a car with a lighter one.

Better gear choices could help stop this being problem - you may be able to avoid needing to upshift at points where you aren't happy to take a pause of a couple of seconds, or alternately sometimes taking an earlier (lower revs, so less drop needed) 1->2 followed by running most of the way through 2nd may save you time overall.

If you absolutely need a faster upshift, you could use the clutch to speed the change up, in which case you'd need to bring it up to somewhere around the biting point and use it to slow the engine artificially. If you're getting a jerk when trying to do this, you must be lifting the clutch too far too soon.

Driving uphill exacerbates the challenge, because your road speed (and therefore required revs) will fall faster than normal, while the engine will slow at its usual rate. Conversely you can upshift faster downhill without slipping the clutch.

What are you driving? I don't know that I've ever been in anything where the revs drop so slowly when declutched that upshifts are cumbersome...

Pyrolol wrote:It depends what you want to prioritize.

If you want to minimize clutch wear, then the only thing you can do is make sure you get completely off the accelerator during the middle of the shift and just wait for the revs to drop far enough before re-engagement. You could also change the flywheel or look for a car with a lighter one.

Better gear choices could help stop this being problem - you may be able to avoid needing to upshift at points where you aren't happy to take a pause of a couple of seconds, or alternately sometimes taking an earlier (lower revs, so less drop needed) 1->2 followed by running most of the way through 2nd may save you time overall.

If you absolutely need a faster upshift, you could use the clutch to speed the change up, in which case you'd need to bring it up to somewhere around the biting point and use it to slow the engine artificially. If you're getting a jerk when trying to do this, you must be lifting the clutch too far too soon.

Driving uphill exacerbates the challenge, because your road speed (and therefore required revs) will fall faster than normal, while the engine will slow at its usual rate. Conversely you can upshift faster downhill without slipping the clutch.

+1

I had a similar problem when I first got my 911 Turbo. I was really struggling to 1) launch the car from stationary and 2) change from 1st to 2nd gear smoothly.

Here are my techniques:
- from stationary: I get the clutch to engage before I use the accelerator.
- 1st to 2nd gear change: Up change at under 1,600rpm/10mph from 1st and revs drop to 1,000rpm for the 2nd and I can change quickly and smoothly. Alternatively, I try to hold 1st a bit longer to get ahead of the traffic, then making a smooth slow change into 2nd if I need more acceleration or directly into 3rd or 4th if I am taking it leisurely. Anything more my old MR2 to my old Mondeos were happy to change from 1st to 4th.

The problem with the 1st to 2nd gear change is partly driven by 1) big gap in the gear ratios between 1st and 2nd, 2) from getting on turbo in 1st to off turbo in 2nd, 3) clutch pedal travel is long, 4) the biting point is in the top half of the clutch pedal travel, and 5) a relatively heavy flywheel.

true blue wrote:What are you driving? I don't know that I've ever been in anything where the revs drop so slowly when declutched that upshifts are cumbersome...

You should try my car then

Garrison wrote:

true blue wrote:What are you driving? I don't know that I've ever been in anything where the revs drop so slowly when declutched that upshifts are cumbersome...

You should try my car then

Is that an invitation?

Rowley010 wrote:Hi,

I'm struggling however, with smooth up changes in the lower gears. Particularly 1st, to 2nd, and 2nd to 3rd. It's either quite jerky, or I have to wait too long for the revs to drop enough to make the change smooth that the car slows down too much and I fail to make enough progress and smooth acceleration.

Hi Richard

Rushed gear changes are often the reason for jerky gear changes, particularly in the lower gears which have the most power. It is unusual for the revs not to drop quickly enough, are you coming off the gas before you put your clutch down to change gear? Some drivers put the clutch down then come off the gas which results in the revs not dropping enough.

What car are you driving, how old is it and do you have access to drive any other cars?.
If the car has a worn clutch, high biting point or a clutch fault it could be almost impossible to change gear smoothly. For example the revs wont drop quickly on a car where the clutch plate wont fully disengage.
Rob

Thanks for replies. Some things to have a go at there!

My car is a diesel Volvo v50

Rowley010 wrote:Thanks for replies. Some things to have a go at there!

My car is a diesel Volvo v50

Is that the one with the Ford TDCi diesel? If so, then I did difficulties too when I first had my Mondeo 2.0 TDCi 130 with a 6-speed box. I adapted to it in the end.

true blue wrote:

Garrison wrote:

true blue wrote:What are you driving? I don't know that I've ever been in anything where the revs drop so slowly when declutched that upshifts are cumbersome...

You should try my car then

Is that an invitation?

My work vehicle is a Fiesta van with the TDCi engine. If I lift my foot abruptly off the throttle when shifting from 1st to 2nd the engine revs are sustained briefly which makes a smooth change hard to achieve. If I close the throttle gently the revs drop and a smooth change is possible. An annoying trait that I think is some sort of anti-stall system.

Yes I do believe it's a ford engine in there.

It seems to be that no matter where I let the revs drop to from between 1st and 2nd I get a jerk. I don't believe there is any clutch issues my car (I have a good mechanic I trust and get it serviced regularly).

The only time I don't get a jerk between those 2 low gears is if I literally only Rev it in 1st to around 1400rpm and then let it drop to 1000 before letting the clutch up, which is clearly no goof when wanting some good firm acceleration without holding up traffic behind, or when want to pull away on a hill!

I understand it's a difficult one to answer without sitting next to me and watching my driving but I'm just after some ideas to be thrown around for me to try out, so thanks for all the replies so far.

I did say I'm getting used to smooth down shifts now, even if some of them still seem like a bit of a stab in the dark with regards to how many revs to give it. I guess that's trial and error and it will eventually become muscle memory on the throttle peddle?

Try not to overthink it.

At the end of the day, it's not magic and your job is simple: get the engine speed as close as possible to whatever it will be at that road speed in the new gear.

The rev counter movement when coming off the clutch will show up how well you're doing this at present.

When you're taught to drive, I think you're probably taught to get off the throttle when changing up, or at least not taught otherwise . In fact you can keep some throttle on if necessary. Aiming to keep your pedal pressure roughly the same will probably serve you reasonably well, except you'll probably also discover that you don't know quite what your foot is actually doing at first.

Cars can also outwit you slightly with anti-stall, non-linear throttle responses and strange cut behaviours, but it shouldn't be enough to really get in your way.

As you imply, it all becomes a bit more automatic after a while.

What I used to do ie what I was taught to do when learning to drive, was to lift off the gas while disengaging the clutch. So as my right foot went up, my left went down. This caused the gear changes to be jerky.

I found that by allowing more time between changes, that I achieved a more gentle transition between gears and that the ride was far more comfortable and composed. I think this came about at around the same time as I stopped high-tailing it away from the lights I also changed the way in which I approached going for the gearstick. Instead of making a grab for it and just moving it as fast as poss from one gear position to another, I relaxed my neck, shoulders and arm. The result of this seems to magically transfer into the gearbox and clutch.

Just give yourself a second or two more to leave one gear and to take another. I'll admit that I don't always do this but that I do know when i've got it wrong. I think it's called something like 'recognising the gate' ie wherever there's a line drawn on the gearknob between the numbers, is 'the gate'. Doing this gives the revs more time to drop and you more time to gracefully and effortlessly change gears, like a hippo swimming through a lake of honey.

Think i'll leave it there

Rowley010 wrote:I understand it's a difficult one to answer without sitting next to me and watching my driving

I'll come and sit next to you soon, I hope.

David