Is double clutch necessary IYO?

It is great for your syncros. If you have an Alfa you have to because the 2nd gear is piss-poor.

You don't have to on the Ferrari but it's like belt and suspenders for protecting the tranny innereds. Plus it's fun once you get used to it.

 

"Double clutching" has no place with modern transmissions.

On the other hand, there's nothing more rewarding than a well-executed heel-and-toe downshift...

 

Should have clarified what "double clutch" means. From the old school--I've been told that to "double clutch" you must:

1. clutch in
2. shift to neutral
3. clutch out
4. shift to next gear
5. blip throttle
6. clutch out

No reason to do that in any modern car. As long as you're shifting quick enough (and I don't mean abusively), engine revs will drop appropriately for the next higher gear.

Cheers

 

Come on whats the real meaning? its not heel toe...

 

no need for double-clutching with syncromesh in modern cars.

 

I didn't think double clutching was necessary, but William H brought it up in another thread & I definitely respect what he has to say - Would like to hear his opinion.

 

Today's transmissions have unbelievable synchro mesh in them that all but eliminate the need to double clutch. That being said, I still find downshifts to be smoother when double clutching, so I do it in my M5 all the time. The basic procedure is...

- off throttle, clutch in, shift to neutral
- clutch out
- rev engine to match lower gear engine speed
- clutch in
- shift to desired lower gear, clutch out

Basically from my understanding, double clutching allows the gears inside the transmission to spin freely to match the speed of the driveline allowing for a smoother "grab" of the next gear. The synchros in today's car take up the difference very well, almost undetectable. I originally found it challenging to double clutch, but now that I have practiced and gotten used to the extra foot motion, I do it all the time. Nothing more gratifying then executing progressive double clutch, heel and toe downshifts from 5th to 4th to 3rd and to 2nd.

 

Double clutching is necessary for older trannys that don't have synchros on all the gears. That said, it's not a bad idea for all cars when downshifting - extends the life of the soft brass synchros, makes the shifter move much easier, and rewards the driver when executed properly.

I always double-clutch - even if it's not technically required.

 

I always double clutch and heel toe. Heel toe shifts have an obvious purpose, not quite as true with modern cars. However, that said, there is no reason not to as well.

Im proud to be the only person in the world that heel toes a Mustang in flip flop sandals on a daily basis Just cant wait until I get a Ferrari!

 

I agree.

 

You do mean slightly higher then desired, so that when you clutch in, shift and clutch out, your rpms are THEN in the right place correct?

 

Auraraptor:

Yes, I guess you could say that. If you are in the reasonable range of the rpm level in thw lower gear (100rpm+/-) you are fine. Thank you for clarifying for others.

 

Nobody else has IMO clearly explained that you are wrong ... thus I will try to explain why you do indeed have to do 2 clutch actions. Lets examine this statement first:

NO!!!!, when you have the clutch depressed the motor and gearbox are separated, ie. the motor is not driving the gearbox input shaft, but the gearbox is most definitely not in neutral.

Thus when you accelerate the engine you are NOT accelerating the gearbox input shaft which is the key to double de-clutching, as it is required to match the gearbox shaft input speed with the output shaft ... and thus the gears and the selector hub are nicely inline, and thus clean change.

BTW: There is a completely separate reason to blip during a down change and that is to prepare the engine for the sudden engine braking load it is about to receive due to the down change. Thus when racing (even if I do not need to double de-clutch) I always blip during down changes to ensure I do not upset the rear tyre grip.

Pete

EDIT: Forgot to answer part of your question, is double de-clutching necessary?

IMO NO, but the blip during the down change (described in the BTW section above) is very important if you are going hard.

 

On a well executed double clutching, combined with a blip of the throttle, you will feel the gear lever almost falling into the lower gear, almost being sucked in even...

If you feel any resistance through the lever/synchro's, you've miss timed it.

The resistance you feel is the synchro's working or the dogs skipping across each other, on a modern gearbox they are so good it's not necessary, but wear is wear, so if you want to save it, double clutch. The modern Ferrari has a TRIPLE synchro in 1st and 2nd and excellent double ones on the others. Even reverse has a synchro. Unfortunatley, the extra synchros mask clutch problems and many cars have baulky gearboxes unnecessarily.

In racing, you'll shift quicker if you do not have to overcome any resistance, so to double clutch may be faster, but only if you can do it properly. Real race cars have no synchros, and huge tough dogs so you can simply smash the lever through the gears without fear of premature failure.

The majority of people simply do it because it feels good....and why not!

 

Pete,

Well put. I was going to respond, but after reading your post, I couldn't have said it any better. Double declutching is not needed. Even in a racing gearbox without synchros (crash box) . Matching the revs between the gearbox and the engine, by blipping the throttle, is good practice when racing so as not to upset the car's balance, possibly lock-up the rear wheels, or worse yet, snap a crankshaft.

 

That's all fun and games until your flip-flop gets jammed between the tunnel and the brake pedal. F****n scary, ask me how I know....

 

I have to agree here. In modern cars, there is no need to double clutch. You can if you want to, but its mostly for older cars, and heavy duty trucks . Going along with Jordan, he may be the only one to heel-toe a mustang, but i'm probably that heel toes a saab turbo on a daily basis in whatever the foot apparel might be.

 

How old are cars that require double clutching? For example will I need to double clutch my 330 GT 2+2 when I get it?

Dan

 

Any gearbox with 'working' synchro's does not need double de-clutching. I do not know if a 330 GT 2+2 has synchro's on all gears but it was common in the 60's for cars not to have synchro's on the first gear and thus you would need to double de-clutch down into first if you wanted to select that gear on the move.

I used to have to double de-clutch my '71 Alfa Romeo GTV and a Simca 1000 I owned because in both cases the synchro's were fncked (especially 2nd gear) ...

Pete

 

I drive a '62 MGA and it requires a double clutch to change gears effectively.
No syncro on the gears is the primary requirement. You can drive it without the double clutch method but you need to be fairly exact with the rpm's. Most people are not good enough at matching engine speed to gear selection properly. Better to double clutch than drop tranny!

 

LOL my best friend does that in his 94 5.0 Cobra all the time...don't think you're alone in this world

- Andy

 

Im crushed

 

Double clutching is good business for throw out bearing manufacturers.