Smooth Gear Changes
Discussion
This may have already been covered but i just wanted to add that how you shift the fear stick can smooth things out as well.
I find that the fastest changes can also be the smoothest because if you have a very short phase where the car is not accelerating/decelerating at the same rate, the jerk is less noticable.
An easy way to speed up gear changes is by flicking the gear lever across the gate very quickly. You don't need to make it a big effort, useing your whole upper body and ramming it home. Quick flicks of the wrist is all that you need to use. Don't try and force it all the way to the stops, just put it in place. This of course depends on your gearbox being precise enough that it doesn't need huge effort to engage gears but hopefully your MGs will be up to the task.
I almost place pre tension on the shift before i start the gearchange rather than waiting till i have started to dip the clutch.
Hope this makes sense.
I find that the fastest changes can also be the smoothest because if you have a very short phase where the car is not accelerating/decelerating at the same rate, the jerk is less noticable.
An easy way to speed up gear changes is by flicking the gear lever across the gate very quickly. You don't need to make it a big effort, useing your whole upper body and ramming it home. Quick flicks of the wrist is all that you need to use. Don't try and force it all the way to the stops, just put it in place. This of course depends on your gearbox being precise enough that it doesn't need huge effort to engage gears but hopefully your MGs will be up to the task.
I almost place pre tension on the shift before i start the gearchange rather than waiting till i have started to dip the clutch.
Hope this makes sense.
To get a smooth gear change, it is necessary for the speed of the change to match the time needed to match the engine revs to the new gear. If you're changing at low rpm with a relatively small rev change then this may require a snappy change or deliberate action to match the revs. At higher revs it might require a deliberately slowed gear change to give time to match the revs .
LDoR said:
...I find that the fastest changes can also be the smoothest because if you have a very short phase where the car is not accelerating/decelerating at the same rate, the jerk is less noticable.
...
I find that the fast changes are smooth until I miss one. Then they aren't so good.
This sounds exactly the same symtoms as I was suffering as a passenger in my wifes car. Some careful & polite tips have since resolved the issue.
The main cause was releasing the throttle far to abrubtly (& not quite syncronised with the clutch but dont worry about that) I therefore proposed the following solution for her to practice that worked:
When driving up through the gears, try setting a gentle throttle position, the car accelerates more initially, then at a certain point the car actually stops accelerating and you are just coasting, THIS is point you dip the clutch, you will not feel any jerks whatsoever.
What this demonstrates is at the point of clutch dipping there should be no power through the driveline, the car should be coasting along with only very minimal effort. What you need to practice is going from full or partial throttle back to this coasting throttle. This will help (it did with my wife)
The main cause was releasing the throttle far to abrubtly (& not quite syncronised with the clutch but dont worry about that) I therefore proposed the following solution for her to practice that worked:
When driving up through the gears, try setting a gentle throttle position, the car accelerates more initially, then at a certain point the car actually stops accelerating and you are just coasting, THIS is point you dip the clutch, you will not feel any jerks whatsoever.
What this demonstrates is at the point of clutch dipping there should be no power through the driveline, the car should be coasting along with only very minimal effort. What you need to practice is going from full or partial throttle back to this coasting throttle. This will help (it did with my wife)
cptsideways said:
....in my wifes car. Some careful & polite tips .....
Very wise, very wise indeed!
If I may task you all even further, I feel that I am getting better with the upshift. I'm dropping off the revs slightly before the change, and it appears to be working. However, on the downshift, I know that I should match the engine revs to the road speed, but I have 3 main queries.
1) how do I know what they should be. 4th to 3rd at 60mph requires different engine revs that 4th to 3rd at 30mph. I appreciate that this comes with experience, but is there a guideline to practice with initially.
2) should I be dabbing the pedal, almost a short stab, or should it be a deliberate pressure increase (which obviously would take longer).
3) to match the revs takes me longer than not matching the revs, so the gearchange is longer. Is it okay to be doing a longer, more deliberate change, or should it be snappy happy.
Thanks to everyone, and I only wish I had advice I could offer you rather than always the other way around.
Regards
Sally
Sally - getting it right is more important than making a snappy gearchange. That will come naturally later on if you are so inclined. In the meantime give yourself plenty of time to make leisurely gearchanges so that you have a chance to note what happens, think about it, and see what you think might work better next time.
As for offering advice and help to others here - that's a nice thought and you are already in a position to do it, even as a relatively new driver. Helpful suggestions can come from anybody, anywhere, any time. Even a simple question can be a useful prompt.
Best wishes all,
Dave.
As for offering advice and help to others here - that's a nice thought and you are already in a position to do it, even as a relatively new driver. Helpful suggestions can come from anybody, anywhere, any time. Even a simple question can be a useful prompt.
Best wishes all,
Dave.
GreenV8S said:
If you have got the throttle right, when you dip the clutch the revs won't change. It's worth challenging yourself to do this from time to time. Similarly when you engage the clutch, you should not feel a lurch as the clutch drags the engine speed up or down.
TripleS - many thanks for your kind comments.
GreenV8 - I dont understand your first comment above when you say that the revs wont change when I dip the clutch. Wont the revs always change when the clutch is first depressed, mainly because I'm coming off the accelerator. Or, or you saying that I'm changing too early, and a higher rev would stay higher (if that makes sense).
Regards
Sally
GreenV8S said:
If you have the throttle exactly neutral, so that the engine is not applying any acceleration or decelleration to the car, then when you disengage the clutch the revs won't change at all.
Can you talk me through this please. Assume I am out on the open road, in 2nd, accelerating up, ready to go into 3rd.
Can you let me know what to do, when and how, because I would like to go out and practice. Do I get it to xk revs, and what should they be, and do I back off fully, etc. Your comments would be most appreciated.
Regards
Sally
GreenV8S said:
If you have the throttle exactly neutral, so that the engine is not applying any acceleration or decelleration to the car, then when you disengage the clutch the revs won't change at all.
Not sure that I understand this either unless I am taking it out of context. If you are going along at a steady speed, ie the car not accelerating or decelerating, then the engine is working to overcome friction. If you remove this load from the engine by declutching, surely the engine revs will rise?
Graham
earlier I posted that I had not conciously noted the need to keep any gas on in upshifts. Well I have been analysing my driving in a couple of the cars I drive...
In the Galaxy, the revs take weeks to drop, gear changes can go as slow as you like and there is no jerk on re-clutching (if that is the opp of de-clutching!).
In the Caterham, if you do a slow upshift, you do have to raise the revs. I was not aware that I was doing that, but I def am. If however, you do a quicker shift (as it was designed to do) having used more revs in the prev gear, the changes are very very smooth. It was clearly designed that way!
Graham
In the Galaxy, the revs take weeks to drop, gear changes can go as slow as you like and there is no jerk on re-clutching (if that is the opp of de-clutching!).
In the Caterham, if you do a slow upshift, you do have to raise the revs. I was not aware that I was doing that, but I def am. If however, you do a quicker shift (as it was designed to do) having used more revs in the prev gear, the changes are very very smooth. It was clearly designed that way!
Graham
Ahhaah
Nearly there !!
As you accelerate gently squeeze the pedal, then gently release before the gearchange. The critical part is to have a very light throttle at the point of dipping the clutch (not on hard, & not completely off)
A quick test: Drive along a nice straight open road 40odd mph say in 3rd gear, HOLD the speed then dip the clutch whilst holding the throttle fixed in that place. The revs will rise but not by much matbe 2-300 rpm if you've got it right. Do this a few times & practice frequently until it becomes natural.
If you now maintain that throttle you will also find smooth into 3rd gear changes appear (when you lift the clutch) as the revs are aleady in about the right place.
What you are now doing is rev-matching & this is the essence of smooth gearchanges
>> Edited by cptsideways on Sunday 2nd April 21:09
Nearly there !!
As you accelerate gently squeeze the pedal, then gently release before the gearchange. The critical part is to have a very light throttle at the point of dipping the clutch (not on hard, & not completely off)
A quick test: Drive along a nice straight open road 40odd mph say in 3rd gear, HOLD the speed then dip the clutch whilst holding the throttle fixed in that place. The revs will rise but not by much matbe 2-300 rpm if you've got it right. Do this a few times & practice frequently until it becomes natural.
If you now maintain that throttle you will also find smooth into 3rd gear changes appear (when you lift the clutch) as the revs are aleady in about the right place.
What you are now doing is rev-matching & this is the essence of smooth gearchanges
>> Edited by cptsideways on Sunday 2nd April 21:09
gridgway said:
Not sure that I understand this either unless I am taking it out of context. If you are going along at a steady speed, ie the car not accelerating or decelerating, then the engine is working to overcome friction. If you remove this load from the engine by declutching, surely the engine revs will rise?
Graham
When you disengage the clutch, the transmission will be unloaded and the car will be coasting (constant speed, apart from the very very slight decelleration from the drag on the car). The point of going to a neutral throttle before you disengage the clutch is so that the transition from accelerating to coasting occurs smoothly as you roll off the throttle, rather than abruptly as you disengage the clutch.
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