dennis50nj

there is no reason to even use the clutch at all except for starting and stoping

DANNOV

The catch is: that to be proficient at double clutching you have to do it all the time. It has to be done automatically, without thought. I frankly cannot downshift without a double clutch, it is ingrained into my driving style. I am not talking just about on the track, I do it on the street and on the track, all the time. 100% of the time!
As to your comment about added clutch wear, I might add that the GM automatic 1st to 4th skip shift, that everyone complains about (not me), is probably is the biggest saver of clutch, pressure plate and throwout bearing wear that anyone can imagine. Let everyone gag on that thought!
I don't think wear is an issue, anyone who drives on the street in city traffic, will probably put far more wear on the clutch components than several track sessions.

6 speed Sid

For street driving, just give it a blip of throttle as you pass thru the neutral gear position and you will be fine. No manual tranny problems in 40 years like that.

30YR W8T

I appears you are speaking from experience too.

C6dude

Heel and Toe is the way I go

Craigster05

Ive been doing it this way since I was 16 and got my first 72 Camaro 350 back in 76 ( Geez, Im getting old). I ran hard on many different cars through the years and never, ever had a transmission or rear end failure.

Of course I dont race anymore, but I do go fast so as not to have that disappointed look on the young girls faces when they catch me and see me driving my car instead of my son.

AraiGP4

The driving schools teach you to double clutch because their Formula Ford/Formula Dodge open wheel single seaters come with Hewland type racing gearboxes that use straight cut gears and dog rings instead of synchros. The technique makes gear changes easier and reduces wear on their equipment. Actually, with a well maintained Hewland gearbox, you don't need to use the clutch at all to change up or down, providing you know how and when to blip the throttle while doing so.

It is unnecessary to double clutch when using a synchromesh gearbox, such as that found in the C6. The only exception to this is when you are stopped and the damn thing doesn't want to engage first from a rest. Then, double clutching allows the internals to get spinning properly so you can select first.

I agree with all who advocate the heel and toe method of changing down. You do not get the full benefit of a manual gearbox unless you have mastered this technique and the C6 pedals are perfectly placed for doing so.

RBYCC

Not just extending synchro life, but also clutch life....

OttoNP

"Your comment about double clutching on the upshift is not correct. In the upshift situation the input shaft needs to slow down somewhat in order to syncronize with the next highest gear ratio and this happens naturally as you back off the throttle and depress the clutch"

It depends on when you depress the clutch, as soon as it disengages the layshaft will remain at the higher speed. For instant let's say your engine is at 7000 in 1st which is the same as 3000 in 2nd. When you upshift, you speed up the engine to 7000 and put the clutch in, so layshaft is still at 7000. Then you let off accelerator and the engine slows down to 3000. As you push into 2nd the synchros will slow the layshaft down from 7000 to 3000. On a downshift it speeds the layshaft up from 3000 to 7000, so you see it's the same.

Unless you slow the engine down to 3000 with the clutch still engaged...which you wouldn't do...then you wouldn't need to shift.

I almost always push clutch in before coming off the gas, if you come off gas too early, you get jerky shift.

AU N EGL

DANNOV

I am not sure I follow your reasoning. In any case, the statement from my post was not mine, it is a direct quote from "Going Faster! Mastering the Art of Race Driving" published by The Skip Barber Racing School, page 99 paragraph, entitled "Upshifting". Here it is again in quotes, together with some additional quotes.

"In the upshift situation the input shaft needs to slow down somewhat in order to syncronize with the next highest gear ratio and this happens naturally as you back off the throttle and depress the clutch." Also, here is more: "There is absolutely no need to blip in the middle of the shift" and "Blipping between upshifts only makes the mismatch worse" refering to syncronizing with the next highest gear.

In a following paragraph of the book they discuss "power shifting" and note that thsi method is not advisible for road racing. I am not sure if you are talking about "power shifting" but I just want to eliminate that possibility from the discussion.

I have driven the Formula Fords at the Skip Barber School at Road America for quite a few laps. The cars use racing gearboxes, no syncros. To downshift you must double clutch, but on upshifts I have never double clutched. The Skip Barber instructors specifically tell you not to double clutch on upshifts and not to blip the throttle either. This is also in their book on page 99. I might add that anyone going to the Skip Barber school should learn double clutching before they get there.
For many students learning how to do a double clutch downshift while heel and toeing can be a frustrating experience. A student can learn this technique himself and save a lot of expensive track time for the better stuff.

If your statement is correct, I should have experienced difficulty on my upshifts. In fact the upshift were the easy part, i.e. clutch in, come off gas for a moment, shift to next higher gear, release clutch, get on gas.
I can only relate my personal experience, and what is taught at the Barber school, and it seems to conflict with your point. So if you do not need syncros to smoothly upshift when using a non syncro racing gearbox, I contend that they likely do not come in play when upshifting on a fully synco gearbox as in a C6.

OttoNP

There may be something specific about that kind of transmission, my comments are only on synchromesh transmissions (C6). I suppose the friction from bearings and slight contact between clutch plate, pressure plate and fly wheel would slow the input shaft when upshifting, but they would speed it up as well while downshifting. Also, perhaps the RPM difference is greater when downshifting then upshifting as well as bearing losses will only slow down input shaft.

Also, http://auto.howstuffworks.com/transmission1.htm, does a good job of explaining it.

Searching around the net on racing transmission has also revealed that many modern racing transmission do not have all gears engaged (non-synchromesh gearbox), but only the drive gear. This saves on loses and leads to more efficiency, but requires double clutching.

sunsetZ51

ill only double clutch if im on the highway during aggressive driving. but as stated above it does add 1/3 more wear on the clutch disc and bearings.

PaBlueCoupe

Some discussion!

excessive81

as other have said before spring mountian beats the crap out of their cars. guess what meathod they teach....heel toe!!!! why because back when i was born they made syncros for manual tranny's eliminating the need to double shift. don't know about you but whatever spring mountian says i do!!!! but to each his own like always

vettesmith02

The trucks that I drove did not have synchros and double-clutching was necessary, we used to tear up the transmissions by seeing if we could just shift from one gear to another by playing with engine speed and leaving the clutch engaged. Some guys could do it without grinding the gears. Surprisingly, those Internal Harvestors made over hundreds of thousands of miles without rebuilding (but I bet the fluid changes had a fair amount of steel coming out during draining though ).

It's not necessary to double clutch with the Corvette. You aren't saving anything including gas by bringing the the RPMs back up to speed. This car will take it and we find a way to abuse it in so many other ways.

Joecooool

Double clutching should be dead. The "**** and the curious" brought the outdated idea back into the mainstream.

With today's cars, there is no way - absolutely no way - you could get a faster 1/4 mile time or better autocross time using this antiquated shift method.

30YR W8T

Double clutching should be dead. The "**** and the curious" brought the outdated idea back into the mainstream.


You should really learn how to express yourself and just let it go, don't sugar coat it or beat around the bush, just come out and say what you really feel. This will reduce stress and make you feel alot better.

markbrown

I can shift gears without a clutch at all. It's all in blipping the throttle. Learned the method thru years of motorcycle riding. I will say I have not done this with my new Z as the transmission shifts great and I see absolutely no need to double clutch. I was wondering why all you double clutch'ers were in my rear view mirror.

lockshed

I just floor it and go, A4 vert 05. But in my other car, I guess I use the jerk and release method or is it the rthym and pull Rosey tactic. Whatever, this board is cool but there is way too many posts on some subjects like this that. I am told the average Corvette owner is between 45 and 56, act your age boys, go get laid or better yet, heal and toe your wives or something, double clutch a stripper, but please, four pages on this topic is a little overkill. Friggin Nerds. Late, love you all.