Smooth Gear Changes
Discussion
Many thanks to everyone kind enough to help in the past.
Sorry to be a bother again, but could someone give any tips on smooth gear changes. In particular, the ones from rest, from 1st to 2nd, then 2nd to 3rd, are slightly jerky.
If I can put this into perspective, I don't mean that the passenger is hitting his or her head on the fascia. Rather it is not as smooth as the IAM books and factsheets seem to suggest.
Is there a simple, easy way to practice and perfect this. I find that the main 'jerk' when chaging gear (apart from my rather facetious Husband!) is when de-clutching, rather than taking the pedal back up. The passenger nods (slightly) when I press the clutch down.
All comments from smooth drivers would be most appreciated.
Regards
Sally
Sorry to be a bother again, but could someone give any tips on smooth gear changes. In particular, the ones from rest, from 1st to 2nd, then 2nd to 3rd, are slightly jerky.
If I can put this into perspective, I don't mean that the passenger is hitting his or her head on the fascia. Rather it is not as smooth as the IAM books and factsheets seem to suggest.
Is there a simple, easy way to practice and perfect this. I find that the main 'jerk' when chaging gear (apart from my rather facetious Husband!) is when de-clutching, rather than taking the pedal back up. The passenger nods (slightly) when I press the clutch down.
All comments from smooth drivers would be most appreciated.
Regards
Sally
Simple, take time to do it smoothly & factor that time into your driving plans.
The most important part to being smooth with any of our inputs (Steering, pedals, gears) is to move slowly to start with & then more progressively after that. To an observer our vehicle inputs should never be hurried. We should give off the appearance of a swan, graceful to view from the outside (our actions) but pedaling furiously under the water (working in our minds).
If it is the intial de-clutching that causes the jerk, then declutch slower.
The gear change (up or down) should take a couple of seconds at whatever speed we are travelling at. Just at faster speeds we have to allow more room to travel over whilst doing it.
>> Edited by vonhosen on Tuesday 28th March 22:07
The most important part to being smooth with any of our inputs (Steering, pedals, gears) is to move slowly to start with & then more progressively after that. To an observer our vehicle inputs should never be hurried. We should give off the appearance of a swan, graceful to view from the outside (our actions) but pedaling furiously under the water (working in our minds).
If it is the intial de-clutching that causes the jerk, then declutch slower.
The gear change (up or down) should take a couple of seconds at whatever speed we are travelling at. Just at faster speeds we have to allow more room to travel over whilst doing it.
>> Edited by vonhosen on Tuesday 28th March 22:07
Agree with what VH says
are you sure you aren't lifting off the accelerator AS you start to press the clutch - in other words you might be getting just a fraction of a second of sharp deceleration just before the clutch disengages.
try pressing the clutch a fraction earlier, and then lifting the accelerator
OR
roll your foot of the accelerator more gradually so that when you press the clutch you're not going from firm acceleration to nothing (which feels like deceleration to 30lb of useless fat aka the passenger's head.)
are you sure you aren't lifting off the accelerator AS you start to press the clutch - in other words you might be getting just a fraction of a second of sharp deceleration just before the clutch disengages.
try pressing the clutch a fraction earlier, and then lifting the accelerator
OR
roll your foot of the accelerator more gradually so that when you press the clutch you're not going from firm acceleration to nothing (which feels like deceleration to 30lb of useless fat aka the passenger's head.)
Things you can try are:
If you are basically engaging the clutch with a bit too much "bang" try lifting the clutch smoothly over the full count of 1-2-3.
Of course, the way to engage the clutch smoothly is to lift in one quick motion to just under the biting point and then to very gently engage the clutch before lifting fully off in another quick motion. Its when we get this latter (best) method wrong that you get a jerky engagement of gear...if this happening to you then try the 1-2-3 slow and smooth thing until you know exactly where your biting point is... and then work from there.
If you are getting a jerk when disengaging the clutch check you do not have your foot on the gas at the time! Do the revs rise rapidly?
If you think you are disengaging and engaging the clutch smoothly but there is still a "jerk" then it is likely it is because during the gearchange the engine revs have dropped to tickover and when you lift the clutch road speed is raising the revs back up to match the speed and the gear combination. If this is happening then the way to smooth it out is to very gently press the accelerator prior to engaging the new gear - which brings the revs up from tickover to the correct level for your road speed - so when the clutch engages there is very little work for it to do...
If can be necessary to match revs to road speed on upshifts and downshifts - but unless you are driving a TVR Cerbera whose revs drop like a stone its most likely this will be necessary on downshifts.
Hope any of that helps. Its a lot harder to describe than the principle of the thing really is...although the required hand and footwork does take a little practice.
If you are basically engaging the clutch with a bit too much "bang" try lifting the clutch smoothly over the full count of 1-2-3.
Of course, the way to engage the clutch smoothly is to lift in one quick motion to just under the biting point and then to very gently engage the clutch before lifting fully off in another quick motion. Its when we get this latter (best) method wrong that you get a jerky engagement of gear...if this happening to you then try the 1-2-3 slow and smooth thing until you know exactly where your biting point is... and then work from there.
If you are getting a jerk when disengaging the clutch check you do not have your foot on the gas at the time! Do the revs rise rapidly?
If you think you are disengaging and engaging the clutch smoothly but there is still a "jerk" then it is likely it is because during the gearchange the engine revs have dropped to tickover and when you lift the clutch road speed is raising the revs back up to match the speed and the gear combination. If this is happening then the way to smooth it out is to very gently press the accelerator prior to engaging the new gear - which brings the revs up from tickover to the correct level for your road speed - so when the clutch engages there is very little work for it to do...
If can be necessary to match revs to road speed on upshifts and downshifts - but unless you are driving a TVR Cerbera whose revs drop like a stone its most likely this will be necessary on downshifts.
Hope any of that helps. Its a lot harder to describe than the principle of the thing really is...although the required hand and footwork does take a little practice.
Wow, quite a lot to think about.
The main time that there is a jerk is only in the lower gears, on the initial de-clutch. Also, if I can put this into perspective, the passengers head only nods an inch or 2. It's just that I want to do it as per the IAM, who say the passenger shouldn't notice the change.
To be honest, the passenger(s) don't say anything, it's just that I notice it when looking for it, checking to see how 'silky smooth' I am.
Reading the above, I am slightly confused. Should I de-clutch before lifting off the accelerator, or should I fully lift off the accelerator before de-clutching. Sorry to be pedantic, but there appears to be different solutions given.
Regards
Sally
The main time that there is a jerk is only in the lower gears, on the initial de-clutch. Also, if I can put this into perspective, the passengers head only nods an inch or 2. It's just that I want to do it as per the IAM, who say the passenger shouldn't notice the change.
To be honest, the passenger(s) don't say anything, it's just that I notice it when looking for it, checking to see how 'silky smooth' I am.
Reading the above, I am slightly confused. Should I de-clutch before lifting off the accelerator, or should I fully lift off the accelerator before de-clutching. Sorry to be pedantic, but there appears to be different solutions given.
Regards
Sally
Lady Godiva said:
Reading the above, I am slightly confused. Should I de-clutch before lifting off the accelerator, or should I fully lift off the accelerator before de-clutching. Sorry to be pedantic, but there appears to be different solutions given.
What I was trying to say was that the problem may be that you are lifting right off the accelerator AS YOU press the clutch, so the clutch is disengaging just a fraction of a second too late, so the car is feeling a slight "bump" of engine braking.
So you can EITHER
press the clutch a fraction sooner so that the engine doesn't get a chance to act as a brake - the problem is that this might result in the engine racing slightly;
or
"roll off" the accelerator more gradually so that the car isn't "accelerating" and then suddenly "not accelerating" (the sudden transition can feel like "deceleration" as the neck muscles compensate and make the head nod forward) - if you roll off the accelerator then the passengers get more of a chance to adjust subconsciously to the change in forces.
The first is a cure for a fairly common driving mistiming - if you're ok, then the refinement you need is in rolling off the go pedal rather than just releasing it.
Lady Godiva said:
Reading the above, I am slightly confused. Should I de-clutch before lifting off the accelerator, or should I fully lift off the accelerator before de-clutching. Sorry to be pedantic, but there appears to be different solutions given.
Don't mean to be confusing! Sorry!
Its a balance thing. Generally you will be mostly off the gas before you declutch.
However if you imagine that you were accelerating hard - and then you just lift off the gas all in one go - there would be a jerk, yes? As a matter of fact you can even destabilise the car and cause a skid of the drive wheels doing that.
So. When accelerating up through lower gears try to feather the accelerator the same way you feather the brake.
The sequence should be something like this:
Into First.
Press accelerator very gently whilst engaging gear.
Foot is now all the way off the clutch.
Press accelerator more firmly. As revs rise consider the next gear.
Press accelerator less firmly to slow the acceleration.
Depress clutch whilst lifting off the accelerator a little more.
Engage next gear. Maintain light pressure on accelerator to stop revs dropping to tickover.
Lift off clutch whilst pressing accelerator very gently.
Press accelerator more firmly. As revs rise consider the next gear...
etc etc
For the downshift:
Press brake gently.
Press brake more firmly until desired speed is achieved.
Press brake gently. Lift off brake slowly but completely.
Move right foot to accelerator.
Clutch in. Engage new gear. Press gently on accelerator to raise revs to match road speed.
Simultaeneously lift off clutch.
Gentlemen - many thanks, that is a lot clearer.
By the way, I've just re read my question above, and it comes across as slightly critical. Can I assure you it wasn't intended, I was simply asking for clarification and assistance. It is my own knowledge I question, not your good selves.
Thanks again, and I will be practicing the 'rolling off' technique this afternoon.
By the way, I've just re read my question above, and it comes across as slightly critical. Can I assure you it wasn't intended, I was simply asking for clarification and assistance. It is my own knowledge I question, not your good selves.
Thanks again, and I will be practicing the 'rolling off' technique this afternoon.
interesting (and clear!) description. Just a thought though, I have never felt the need to keep any gas on between upshifts. If anything many of the more modern cars I have driven have quite a slow rev rate drop, so you have to take longer over the gearchange.
Or did I read the description wrong?
Graham
Or did I read the description wrong?
Graham
I have found the clutchless gearchange quite easy to do in a normal road car and I have had some interesting fun doing that and teaching my left foot to brake (rather than stamp on a clutch). It's just that the gearchange without the clutch is relatively slow getting the revs right, so have found no real benefit on the road.
There would be far too much going on on track to do it!
Graham
There would be far too much going on on track to do it!
Graham
CS's view seems to be that you can then modulate the braking as the downforce (and grip) lightens more effectively than when you heel and toe, provided your left foot is sensitive enough. This strikes me as track technique above and beyond the call.
Back on topic - (one of) the thing(s) that makes your passenger uncomfortable is rate of change of acceleration, or "jerk", rather than acceleration per se (within limits). It's how slowly the trace moves around the g-g space that determines comfort.
Back on topic - (one of) the thing(s) that makes your passenger uncomfortable is rate of change of acceleration, or "jerk", rather than acceleration per se (within limits). It's how slowly the trace moves around the g-g space that determines comfort.
7db said:
Back on topic - (one of) the thing(s) that makes your passenger uncomfortable is rate of change of acceleration, or "jerk", rather than acceleration per se (within limits). It's how slowly the trace moves around the g-g space that determines comfort.
That's what I was trying to say!
gridgway said:
interesting (and clear!) description. Just a thought though, I have never felt the need to keep any gas on between upshifts. If anything many of the more modern cars I have driven have quite a slow rev rate drop, so you have to take longer over the gearchange.
Or did I read the description wrong?
Graham
Nope. You read it right. It depends on the car, the ECU, etc.
Many road cars do indeed have a slow rate of of rev drop. My Vauxhall for one. Its actually done deliberately (and electronically) to make upshifts smooth and easy to do.
Many sports models however adopt the view that throttle response is king (up and down). My mate's TVR Cerbera (for example) if you take your foot off the gas and declutch goes to tickover immediately - the revs drop like a stone! So you *have* to maintain some throttle pressure to smooth out the upshift.
My Boxster S also has very swift throttle response: It makes doing heel and toe downshifts a snap...
7db said:
It's how slowly the trace moves around the g-g space that determines comfort.
Oh absolutely 7db, I know exactly what you mean. NOT!
Don't forget, the only g-g I'm involved with is the 14h Welsh cob my daughter rides.
However, I believe understand your general thrust, in that the change, rather than the acceleration itself, is the problem area.
The good news is that I was out last night practicing the 'roll off the pedal' tip and it appears to work wonderfully. It's almmost a case of relaxing the foot such that your mind knows it's done it, without being able to say there is the movement. If you can feel the movement, it's almost backed off too much. Does that make sense?
In practice, I was tootling along in 1st, then I prepared to change, relaxed the RF slightly, then declutched and fully backed off, and watched my passenger's head out of the corner of my eye. Super, no movement at all. Very pleased indeed.
Re the revs dropping, I've found that in the MGF the revs do drop quickly (although nowhere near as quickly as a Cerbera or Porsche). Because of this I always give a little gas coming back into an upshift.
However, I've read what cars you boys drive, and they seem to be rather powerful, and exude testosterone. One of the threads above referred to sports cars dropping the revs, and I've always wondered about the MGF. Do you see it as a sports car, or is it only things like the Cerbera, Caterham, etcetera, that you see as 'proper' cars. Where does my baby come into it.
that must be something that I compensate for without thinking Don. I have driven quite a lot fo cars with sharpish throttle response, so must be compensating on the upshift without really thinking about it.
Lady G, the MG-F is in the sporty bracket, not quite sure how sporty the k series engine in it is, but it'll definitely be on the sporty side rather than on the "revs-holding-up" side! The induction, ecu mapping and flywheel size affect sporty it is. The 1400k in my daughter's rover 25 keeps the revs up a bit, the 1800k I had in my caterham R500 had pretty sharp response and was quite hard to drive smoothly especially in low gear and small throttle openings.
Re CS's ideas, I can see what he means in theory, but he must have some "race-car" transmission stuff to get a good clutchless change. I struggle to keep the braking on track smooth whilst heel and toeing expecially in the wet when the pressure on the brake peddle is less.
Graham
Lady G, the MG-F is in the sporty bracket, not quite sure how sporty the k series engine in it is, but it'll definitely be on the sporty side rather than on the "revs-holding-up" side! The induction, ecu mapping and flywheel size affect sporty it is. The 1400k in my daughter's rover 25 keeps the revs up a bit, the 1800k I had in my caterham R500 had pretty sharp response and was quite hard to drive smoothly especially in low gear and small throttle openings.
Re CS's ideas, I can see what he means in theory, but he must have some "race-car" transmission stuff to get a good clutchless change. I struggle to keep the braking on track smooth whilst heel and toeing expecially in the wet when the pressure on the brake peddle is less.
Graham
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