Double Declutching

[yannick]

I occasionally analyse my driving, and recently I noticed that under certain conditions I double-declutch on a downshift.

I know that modern gearboxes really don't need it, but I find that it gives a smoother change.

I was wondering how dated I was, or is there anyone out there that still does it?

[Funkadelic]

All the time. I nearly always heel-and-toe as well although the pedals in the MR2 are not best placed for it!

Don't worry - I know a load of people who still double declutch.

It's just good practise, I think. More mechanically sympathetic and if you use heel and toe, you can carry more speed through the bends.

[yannick]

All the time. I nearly always heel-and-toes as well. It's just good practise, I think. More mechanically sympathetic.

Whew, glad I'm not completely alone

I used to heel & toe, but I find the pedal configuration in the Avensis to be incompatible - at least for my feet

[nezerr]

I occasionally analyse my driving, and recently I noticed that under certain conditions I double-declutch on a downshift.

I know that modern gearboxes really don't need it, but I find that it gives a smoother change.

I was wondering how dated I was, or is there anyone out there that still does it?

excuse me if i sound thick but what is double-declutching?

[yannick]

excuse me if i sound thick but what is double-declutching?

You're not being thick, it is a little old-fashioned

I was wondering if I should describe what it was, or if it would be taken as patronising. Obviously I should have.

Here's the deal:

• press the clutch
  
• move the gear level to neutral
  
• release the clutch
  
• blip the throttle (optional)
  
• press the clutch
  
• enter new gear
  
• release the clutch
  

that way you're not relying so much on the synchromesh to match the gear speeds, so it's easier on the box.

[yannick]

Oh, BTW heel & toe is when you do all that while braking. You use the right foot to operate both the brake & the throttle at the same time

[nezerr]

aah rite i c now...lol

wouldnt that put more stress on the clutch making it ware out quicker though?

[Funkadelic]

The real idea behind double declutching is that, when you blip the throttle with the car in neutral, you match the engine revs with the same amount that your car would be doing at your current speed, albeit in a lower gear.

If you get it right your syncros should hardly have to work at all, and this makes life much easier for your gear box - The only way you'll wear the clutch out faster is if you cause it to slip.

Heel and toe, as Yannick says, is the combination of double declutching under braking. It combines braking and downshifting into one smooth movement, whilst simultaniously eliminating drivetrain shunt and clutch braking which, on a track, can mean the few split seconds between first and second place. However, it does mean that you carry alot more speed through the twisties and can feel a little odd at first!

[yannick]

The real idea behind double declutching is that, when you blip the throttle with the car in neutral, you match the engine revs with the same amount that your car would be doing at your current speed, albeit in a lower gear. 

If you get it right your syncros should hardly have to work at all, and this makes life much easier for your gear box.

As he said, it's easier on the box, and as you are doing the changes in engine speed while the clutch is engaged & in neutral, it should be easier on the clutch as well. The only thing that really gets used more are the clutch springs & the pedal

Edited: oh, and your foot as well

Edited March 16, 2004 by yannick

[kimi]

just drove round the block to try this clutch thingy out

it lost me i nearly smashed the thing up i was

concentrating on clutch forgot to brake :shutit: the way i see it

the gearbox is under warranty for 3 years so think ill press clutch

once ! it was fun trying it though :P

luv kimi

[GIDDLEPIN]

Double declutching steams from the old crash box days (I can only just remember them ), I used to do it regularly untill I took my HGV 1 recently, it was only when the instructor said " What do you think you're doing, the examiner won't accept that on your test as it could be classed as not beeing in full control of the vehicle!

The other things I used to do were progressive braking on emergency stops and changing down through all the gears, all no-no's now.

[hachi-roku]

My driving instructor used to be a high pursiut driver for the police, and after my test he showed me how to double declutch... in a 1.6 Focus He made that thing come alive, which shocked me.

My 86 gets double declutched and Heel-Toed all the time, force of habit really, but it's an engine that really needs to be kept on the boil otherwise it seems rather lazy :)

[yannick]

Double declutching steams from the old crash box days (I can only just remember them ),

I learnt originally because I had a car with the synchro worn out on 2nd gear. It was either double declutching or triple crunching

[Paul C]

[*]press the clutch

[*]move the gear level to neutral

[*]release the clutch

[*]blip the throttle (optional)

[*]press the clutch

[*]enter new gear

[*]release the clutch

blipping the throttle is not a option when driving a truck you have to do it cause it sounds good when your changing down!!!!

don't do it so much in my car I would rather use the brakes to slow me down than the gearbox as brakes are a bit cheaper to replace

[SuperRetard]

Coming from motorbikes, I found it hard NOT to blip the throttle on the downchange. A bike is so much more dynamic near the limits that anybody who doesn't match the new RPM of the lower gear to their wheelspeed quickly finds themselves snaking all over when changing down and braking...

Trouble is, my hands are now fairly dextrous (independent brake, steering and throttle inputs from the same hand) while my feet are like clubs. Only been driving 6 months! :(

Practice makes perfect tho', and I'm determined to crack the heel'n'toeing lark. I can't stand lurching whilst braking and turning-in! I'm gonna come a cropper if I don't sort it out, been reliant on the ABS a little too much! ;)

Slipping the clutch to match the engine revs really sucks and ain't good for spares/repairs costs I'm sure!

Still, driving over to the proving grounds tomorrow for some performance testing, might get there early and polish off the Toyos, errr... I mean "dry the racing line off, boss!" :P

[Dame]

I originally learnt on one of our old landrovers, the series II's don't have syncro boxes so double de clutching is vital. I still forget now and do it on the '2.

[yannick]

If anybody is curious as to exactly what "Heel & Toe" is, here is an article.

For more info, just do a search on Google. There are loads of sites that explain how to do it.

[Yarisboy]

I was under the impression that double clutching & heel toe were as stated; methods used to help older gearboxes....

however I also thought, as briefly touched on by someone; that these methods are carried through into track driving as it helps to maintain more speed through the bends.

It's only of any real benefit to highly tuned race monsters these days though?

[yannick]

As mentioned, double declutching is mainly for older gearboxes without synchro. If you continue to use it with modern gearboxes the real advantage is smoother changes and less wear on the hardware. :hokus-pokus:

Heel & toe is uniquely a motorsport thing. It is used to be able to maintain the engine at the correct speed while breaking & downshifting at the same time. It gives you a lot more control over your car on the approach to, and in, the corner.

Now that we've got that sorted - who's up for a discussion on left-foot braking

[Ryan1985]

Left foot braking - i nearly went thru the windscreen!!!

[cal]

I tend to do it as well since my car is getting on a bit, certain gears won't go in smoothly as it used to. Still no too bad but just to reduce the beating it gets... :D

[Chappers]

Left foot braking - i nearly went thru the windscreen!!!

Ha ha, have u all tried that?

I too nearly went thru the windscreen first time..............eek

[Funkadelic]

Sod left foot braking. Can't do it.

[yannick]

Sod left foot braking.  Can't do it.

Practice makes perfect.

It's a very useful technique for rallying, but it does take some getting used to. Your left foot just isn't as sensitive at the start, but you can get it right... eventually.

I had to, because I rallied SAABs, where the handbrake is on the front wheels. Others did handbrake turns, I had to use my left foot

[yannick]

Forgot to mention that I don't use the left foot in my current car. But for some reason I do when I drive automatics. Just a bad habit that I picked up somewhere