Double clutching to save wear on Synchros

thethedev

Hi Guys.
It would be interesting to get some opinions on this.
I always double clutch my car both up and down through the gears, I really only do it for the craic purely because I love driving(heel toe braking+double clutching=sex:D)
Anyway I reckon that doing this saves wear on the baulk rings in the box because they are not being used as much and it puts less pressure on the clutch if at the time of engagment both plates are spinning at the same speed.
I could be wrong on this but a friend reckons its completely pointless on a modern car as they have already been set up to take the extra strain and theres no need with a modern transmission anyway.
Any ideas folks?
Either way I suggest you try it because it sounds cool to:pac:

peasant

If your car has a synchromesh gearbox it is recommended you do not double-de-clutch as this can cause undue wear on the synchro rings. TC

http://www.singster.co.uk/mascot%20mar-apr%202003%20(4).html

... because you're in effect using the syncro rings twice as much

(not to mention the clutch)

Mr Benevolent

thethedev wrote: »

Hi Guys.
It would be interesting to get some opinions on this.
I always double clutch my car both up and down through the gears, I really only do it for the craic purely because I love driving(heel toe braking+double clutching=sex:D)
Anyway I reckon that doing this saves wear on the baulk rings in the box because they are not being used as much and it puts less pressure on the clutch if at the time of engagment both plates are spinning at the same speed.
I could be wrong on this but a friend reckons its completely pointless on a modern car as they have already been set up to take the extra strain and theres no need with a modern transmission anyway.
Any ideas folks?
Either way I suggest you try it because it sounds cool to:pac:

There's really no need double declutch becuase of the synchromesh, but it sounds like fun. Everyone I know who tried it nearly went through the windscreen though

BlackWizard

So does rev matching help at all with the wearing of parts?

thethedev

peasant wrote: »

http://www.singster.co.uk/mascot%20mar-apr%202003%20(4).html

... because you're in effect using the syncro rings twice as much

(not to mention the clutch)

I thought I was eliminating their need to even be there thus saving wear.
I'm sad now:( :P
I'm still going to do it because its fun:P

peasant

BlackWizard wrote: »

So does rev matching help at all with the wearing of parts?

you could rev-match wihout double clutching ... at least when shifting down, but I don't quite see the point

mickdw

Double clutching is not of any benefit anymore I think. I do like to do a bit of heal & toe though when Im pushing on abit.

dnme

Can anyone explain Double clutching? What is it?

guil

clutch-move to neutral-clutch again and select gear

Mr Benevolent

gt112 wrote: »

Can anyone explain Double clutching? What is it?

From Wikipedia:

In a gearbox with neutral between each gear, a typical shift actually involves two gear changes, once into neutral, and again into the next gear. During any shift, disconnecting drive components via a clutch properly unloads the engine and transmission of undue pressure applied by the opposing components. Fully utilizing the clutch for each shift out of, and then into each gear is double clutching

asea

gt112 wrote: »

Can anyone explain Double clutching? What is it?

try this link to one of the pioneers of this technique in rallying http://www.youtube.com/watch?v=65iD4gkelfg

dnme

asea wrote: »

try this link to one of the pioneers of this technique in rallying http://www.youtube.com/watch?v=65iD4gkelfg

I'm on mobile broadband, I get about 14kbps so youtube is not my friend. Can anyone explain double cluttching ?

guil

gt112 wrote: »

I'm on mobile broadband, I get about 14kbps so youtube is not my friend. Can anyone explain double cluttching ?

you were told twice already

dnme

ooops sorry, I didn't see the posts previous to the youtube link. So, lemmie get this straight..

1. Its clutch, take it out of gear to neutral
2. Clutch out
3. Clutch in again
4. Into next gear
5. Clutch out again

Why would you do this? Why do some above describe it as fun?

asea

gt112 wrote: »

I'm on mobile broadband, I get about 14kbps so youtube is not my friend. Can anyone explain double cluttching ?

sorry if i seem a bit arrogant, but if you really want some insight to the practice of double clutching ,heel and toe and rev matching then i suggest you make the effort to access the rallymaster's video on youtube on a strong connection elsewhere if your mobile B/band is not up to it, or get the dvd it would certainly answer your questions,

Big Nasty

Double Clutching? Waste of time this day and age IMO! Effective if not necessary 50 years ago but not much use now.

peasant

gt112 wrote: »

Can anyone explain Double clutching? What is it?

It means that during the gearchange you introduce an extra step where the clutch is out and the gearbox in neutral. This allows for the engine speed and gearbox speed to be matched (in case of shifting down you have to blip the gas, shifting up you allow the engine to slow down). Then you press the clutch again, put in the right gear and let it out again.

dnme

Thanks everyone for the replies. I kinda think myself though that life is a little too short, or am I missing the point

**Timbuk2**

OK, sorry to sound stupid, but I still don't get the point of double clutching. When you are changing down gears, if you clutch in, aren't you taking it out of gear, i.e. neutral. Taking the clutch out in neutral won't make any difference, will it?

peasant

**Timbuk2** wrote: »

OK, sorry to sound stupid, but I still don't get the point of double clutching. When you are changing down gears, if you clutch in, aren't you taking it out of gear, i.e. neutral. Taking the clutch out in neutral won't make any difference, will it?

When you press the clutch pedal, you interrupt the connection between engine and gearbox, you're not automatically in neutral.
Neutral is when the gearstick is between gears, in the middle position.

On modern gearboxes there is no point in double clutching ...that's what the syncromesh is for.

This vid is of an old truck without syncromesh where you HAVE to double-clutch in order to shift gears ...only that yer man ins't very good at it ...listen for the crunching noises

https://www.youtube.com/watch?v=Vg1FTZduqRg

bladebrew

**Timbuk2** wrote: »

OK, sorry to sound stupid, but I still don't get the point of double clutching. When you are changing down gears, if you clutch in, aren't you taking it out of gear, i.e. neutral. Taking the clutch out in neutral won't make any difference, will it?

+1 im lost,when changing from 3rd to 4th (for example) you clutch in,put it into neutral,clutch off,???,clutch in then into 4th?

peasant

bladebrew wrote: »

+1 im lost,when changing from 3rd to 4th (for example) you clutch in,put it into neutral,clutch off,???,clutch in then into 4th?

The engine/gear combination at the same speed turns slower in 4th than it would in third.

When you're shifting down from 4th at say 2000 rpm you end up in 3rd at 3500 rpm (for example)... the difference of 1500 rpm has to be matched somehow for the gears to be able to engage.

On a modern gearbox the syncromesh takes care of that.
On a non syncro gearbox you have to: clutch in - engage neutral -clutch out - spin engine & gearbox in neutral near to 3500 rpm - clutch in - select 3rd - clutch out.

If you don't get it rigth 3rd will not go in and you'll hear that terrible grinding noise instead

W.Shakes-Beer

bladebrew wrote: »

+1 im lost,when changing from 3rd to 4th (for example) you clutch in,put it into neutral,clutch off,???,clutch in then into 4th?

its used more so if you were going from 4th to third i think.


pointless imo but something to try when out on the road on a quiet night :P

unkel

My late grandfather passed his driving test 80 years ago. He had to double declutch in the small truck he passed his test in (and the indicators were hand pulled and his seat was a sack of spuds - but that's asides). And even way back then the synchromesh had already been used in some cars.

Now move on folks - it's 2010 and that silly little third pedal (counting from right to left) will be gone soon

peasant

unkel wrote: »

Now move on folks - it's 2010 and that silly little third pedal (counting from right to left) will be gone soon

I have to say though, it is immensely satisfying when you get handed one of those non-syncromesh monsters (like in my vid above) and after some crunching you actually get to drive it like it's meant to be driven.

Automatics are girly stuff

unkel

peasant wrote: »

Automatics are girly stuff

At least us girls get to 100km/h in single digit seconds, not minutes

peasant

That yoke I mentioned has the manly top speed of









78 km/h

bladebrew

peasant wrote: »

The engine/gear combination at the same speed turns slower in 4th than it would in third.

When you're shifting down from 4th at say 2000 rpm you end up in 3rd at 3500 rpm (for example)... the difference of 1500 rpm has to be matched somehow for the gears to be able to engage.

On a modern gearbox the syncromesh takes care of that.
On a non syncro gearbox you have to: clutch in - engage neutral -clutch out - spin engine & gearbox in neutral near to 3500 rpm - clutch in - select 3rd - clutch out.

If you don't get it rigth 3rd will not go in and you'll hear that terrible grinding noise instead

christ that sounds like a lot of work:)
but how would you know if you were at the right revs to downchange?

unkel

peasant wrote: »

That yoke I mentioned has the manly top speed of









78 km/h

Grand. At least that will mask the difference in performance between a pro and an amateur (like me and about 99.99% of all drivers). I'd rather be as fast as a pro though

mickdw

bladebrew wrote: »

but how would you know if you were at the right revs to downchange?

Experience & skill.
For example, if you drive a car, you will have a fair idea of what kind of revs the engine is going to rise to as you engage 2nd gear from 3rd as you slow for a junction. You will know that you are not going to send the revs off the scale. So taking that further, you should be able to blip the throttle to that amount of revs before the lower gear cuts in if you have gotten to know the specify car for a few miles.

lucky-colm

i blew the gearbox out of a transporter once:D

would double clutching have saved me there

i think not considering van and trailer was 6.75 tonnes most of the time

JHMEG

Some manufacturers make soft gearboxes, some don't. Double clutching won't help... if the gearbox is badly made it's badly made.

vengeance52

asea wrote: »

try this link to one of the pioneers of this technique in rallying http://www.youtube.com/watch?v=65iD4gkelfg

Great video that. Perfect demo of Double clutching and heal toe breaking. Good commentary about rallying in general.

peasant

bladebrew wrote: »

christ that sounds like a lot of work:)
but how would you know if you were at the right revs to downchange?

actually, its not too bad

Shifting up is really simple. By the time you have the clutch fully down, neutral in, fully out, fully in and gear selected, it will glide in smoothly ...once you got the knack it's a bit like a left foot tap-dance.

Shifting down, the secret is not to try and think about it. The more you theoreticise about it, the longer it takes and the less chance of a successful gearchange.

Clutch down, neutral, clutch out, a good tap on the gas, clutch down and then the knack is in easing the selected gear in as the revs go past the correct range (as they drop pretty quickly again after the blip on the accelerator). If you don't try to force it too much, the gear lever will actually give you the feedback when it's ready to go in.


I gets really interesting though, once you mess up your gearchange and the 10 ton truck starts trundling down the hill in neutral, getting ever faster and no gear willing to engage :eek:
That way you learn to read the road and to change gears before it gets critical

Barname

@OP

What sort of eejit double clutches?

it is 2010

having your car in neutral for no reason (read extended periods) affects your inertia and as such makes your car less controllable

if you were any good of a driver you would have 'felt' this

Marlow

asea wrote: »

try this link to one of the pioneers of this technique in rallying http://www.youtube.com/watch?v=65iD4gkelfg

Have to agree with vengeance52: perfect demo of double clutching, heal toe breaking and good commentary about rallying.

Thanks for posting that video.

Double clutching isn't of any use anymore, beyond some of the old rally-cars and if you follow the video, you'll hear, that they only apply it, where it makes sense.

/M

Mr Benevolent

Barname wrote: »

@OP

What sort of eejit double clutches?

it is 2010

having your car in neutral for no reason (read extended periods) affects your inertia and as such makes your car less controllable

if you were any good of a driver you would have 'felt' this

That's been covered. It's a mainly theoretical discussion now

thethedev

Barname wrote: »

@OP

What sort of eejit double clutches?

it is 2010

having your car in neutral for no reason (read extended periods) affects your inertia and as such makes your car less controllable

if you were any good of a driver you would have 'felt' this

I don't think you fully understand this, the car isn't in neutral for very long at all.

Actually now that I'm fairly proficient at it I have no drive to the wheels for only about the same time as I used to have the clutch in for normal driving.
Its not like I'm coasting for miles in neutral, and luckily I still have a synchromesh box to fall back on in case it goes arse up and I'm stuck in neutral while doing 60 up to a hairpin.
If anything I reckon its a bit safer once you get the hang of it as the car doesn't lurch coming down through the gears throwing all its weight forward and making the back end skittish as you come up to a corner. I know this because I can "feel it".

RoundyMooney

Truck drivers seem to love blipping the throttle between shifts. Whenever I've had to drive one, I just shift slowly, with the same result.

I don't know if its a throwback to non synchro boxes or what.

Anyway, in a car there's no advantage. Engine braking is another things that's shied away from now, under normal driving conditions, as a set of pads is cheaper than dealing with transmission wear.