White BMW 330I

How do you do it? I may already be Double Clutching and not realizing it. Thanks

skabaru

I vaguely remember some article back in the day being this...

you are cruising in say 4th gear, and you want to go to 3rd... so you clutch in, drop to nuetral, cluth out, blip gas enough to match revs to 3rd gear, clutch in, drop to 3rd, clutch out. The 2 hits to the clutch giving it the name... but that was years ago I read that... anyone else?

ColoradoMark

The purpose being to get the internals of the transmission spinning at the same rate so the gears will mesh more easily. Not crucial with a good synchromesh transmission. Critical without synchros or with weak synchros.

White BMW 330I

That sounds similar to what I used to do when I owned Sportbikes. If I wanted to Downshift, I would pull in the clutch, Give it Gas (to keep the revs up), shift down all in one motion, then release the clutch. The revs would then be perfectly matched for the gear and the curve. I now understand the purpose of double clutching. Double Clutching sounds like something that you would do on the track, When Tenths of a second matter. I’m not too sure about the street... I’m getting old!.

Ray Calvo

Explained in archives (nt)

BiggEasy

A4Ever is correct in the procedure. Double clutching is designed to match engine transmission and wheel speeds. If done properly it will eliminate
that "jerk" you feel when downshifting during aggressive driving. Instead,
a properly executed double clutch will feel virtually seamless.

It will take some practice to perform properly. However, its rewarding
to learn. A well driven manual will downshift much smoother than
an automatic.

Biggeasy
98.5 A4 2.8 - Melange

Cameron

Good: 2001 TT Quattro Coupe 225

In sixth at low revs.
Shift to neutral.
Throttle to 5500 rpm.
Shift to fourth.

Bad: 1967 1/2 Lotus Elan

In third at mid revs.
Shift to neutral.
Throttle.
Shift to second and hold it there.
Slowly release clutch.
Repeat last two steps if second is misbehaving.

Some cars need to be double-clutched because a synchro is damaged or worn or there is no remaining synchromesh - a common occurrence on anything built before 1975 or anything British or anything approaching rarity that can call itself Italian with a straight face.

Cameron

Ian S.

As Skabaru says, there is a shift to neutral together with a letout of the clutch as in the following sequence from 3rd to 2nd:
1. Depress clutch pedal and hold in while shifting to neutral.
2. Let clutch pedal out fully and blip throttle.
3. Depress clutch pedal again and shift to 2nd.
4. Let clutch pedal out fully.
When done quickly and smoothly, this will help shifting when syncros are badly worn or under race conditions. I don't see much point to the technique in normal driving when the synchros are good.

JasonB

See home.earthlink.net/~rponiarski/shifting.htm