Quite the contrary, what i'm suggesting is not applicable to 1930s cars or sequential shift race cars, but specifically for modern synchromesh manual gearboxes.

It isn't rocket science to drive a normal modern synchromesh gearbox properly, anyone can do it with practice. Anyone can also get into the habit of doing it wrong and never develop proper technique, and I'm sure this is the norm. Doesn't have to be that way.

 

Rev-matching *does* help, and double-clutching is *never* required outside of exceptional circumstances.
As far as inertia is concerned, you shouldn't be slamming into 2+ gears up or down. Skip shifting is only for benign situations.

I'll just say that if you can skip gears easily without any weirdness, feel free to do so. If the gearbox doesn't like it, it will let you know.

 

LOL I agree with him. Don't do it!

 

I'm no mechanical engineer, but I think I have a good handle on how all this works. So please bear with this terrible drawing I just made in paint:



With the clutch disengaged, no amount of change in engine speed will affect the speed of the transmission input shaft. It's just going to keep doing its own thing (ignoring some friction forces) until one of two things change its speed:

1- The clutch re-engages and forces the input shaft to match engine speed
or
2- You change gears with the clutch remaining disengaged, in which case the snycros will alter the speed of the input shaft to allow the gears to mesh properly.

No amount of change in engine speed while the clutch is disengaged can help ease stress on the syncros, so rev matching (without double clutching) does nothing to make life easier on the syncros.

 

ive read about this before. like others say its the syncros. i dont do it since reading about it a couple months ago. i used to. also, another member once said "you paid for 6 gears use them" haha i figured he had a good point

 

I take it easy most of the time on my rig. I always skip gears if I am rolling smoothly. Up and down, and even drop it in neutral when coasting to a light on occasion.
Around 40k on the Tranny lube since the last change and it came out looking like virtually new (I do use the Amsoil oil type which is compatible with yellow metals in our trans.)
I have no apparent change in normal shifting due to synchro wear and with only 73K I easily still have orig clutch and brakes.
If you aren't pushing it I would say there is no problem at all with skipping gears, but matching engine speed to the appropriate gear when going back into gear is a good practice. Or go easy on the clutch engagement.
You do need to drive the car for a reasonable time to judge the engine speed for proper gear engagement at car speed, especially downshifting due to the S2k's tight drive train and its high compression ratio.

 

Quite the contrary, what i'm suggesting is not applicable to 1930s cars or sequential shift race cars, but specifically for modern synchromesh manual gearboxes.

It isn't rocket science to drive a normal modern synchromesh gearbox properly, anyone can do it with practice. Anyone can also get into the habit of doing it wrong and never develop proper technique, and I'm sure this is the norm. Doesn't have to be that way.
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ZDan has a real point, about having the clutch always engaged while slowing down. Here, if you take a driving test for your drivers license in a standard car, they take points off you for putting it into neutral while slowing down. It is poor practice and generally unsafe. Personally I am always in a gear, but it is not necessary. Its better gas mileage to be in a gear anyways, while slowing down, riding a gear, you use no fuel. Makes no sense to me why people throw it into neutral.

 

This is my most common skip shift. And, for the same reason.

 

Frictional forces acting through the clutch while it is disengaged are negligible compared to forces required to drive the car, they are NON-negligible relative to the rotational mass of the input shaft. That's why rev-matching works, and double-clutching is not required.

Rev-matching downshifts is pretty much *necessary* for autoX/track driving, and useful on the street as well.
And, again, double-clutching is wasted effort, totally UNnecessary.

 

Would you mind elaborating on this a little? When would double-clutching be required or helpful?