double clutch

[noahb270]

i feel like an idiot for asking this but what is double clutching and granny shifting??

[kristen]

Re: double clutch

someone has been watching fast and the furious


Powershifting, grannyshifting, and double-clutching.


Powershifting is effectively shifting without fully releasing the clutch. You keep the gas pedal down while you only use about half the clutch travel to shift hard and fast. This is incredibly hard on a transmission, and in fact simply will not work on most transmissions. Without fully pushing in the clutch on most cars, you can neither pull the shifter out of gear nor put it into a new one (and it will grind as you try).

Granny shifting is when you take a slight pause in neutral between gears when shifting. So instead of going smoothly from 2nd to 3rd, you pull out of 2nd, stop for a moment in neutral along the way, then go into 3rd, and let the clutch out again. Very slow.


And double-clutching? It's like granny shifting except that you actually let the clutch out when you're in neutral, bring up the engine RPMs again, then push in the clutch and go into the next gear. And you do it all VERY fast. This was especially necessary on older cars before synchro gears smoothed the processes of changing gears in the gearbox. It is also a way to avoid grinding gears on transmissions that have been damaged by powershifting too much.

[nikon]

Re: double clutch

OK, double clutching is what you have to do if your synchros go bad, it makes the gear from the engine match the speed of the gear that your going into ( a little more complicated but thats the easy version) btw there is no need to double clutch and if your wondering how you do it, when shifting from say 1-2 you normally clutch in and shift andclutch out, when double clutching you clutch in shift to neutral clutch out, clutch in and shift to second.......and granny shifting (shifting slow) please stop watching f&f its killing our youth.

edit: damnit you beat me.

[HokieBird]

Re: double clutch

Don't blow the welds on your intake manifold. It could cause the floor pan to drop out. :poke:

[black98V6]

Re: double clutch

Don't blow the welds on your intake manifold. It could cause the floor pan to drop out. :poke:

naah man that only happens when you use aluminum daimond deck plating for your floor plan, if you use the smooth stuff it won't happen, less air resistance.

:banana:

[andrew.brandon]

Re: double clutch

naah man that only happens when you use aluminum daimond deck plating for your floor plan, if you use the smooth stuff it won't happen, less air resistance.

:banana:

[mwh27]

Re: double clutch

Don't you have to double clutch in Semi's and other larger trucks also? Because they don't use syncros?

On a side note, anyone hav eany vid of the hydraulic assited stick shift used in rally racing? I saw it on a scooby a while back, saying it was a $20k tranny, but this was way back when paddle shifting was comming into play, and the paddles just moved the stick for you, by way of hydraulics.

[Earnhardt132000]

Re: double clutch

My dad has to double clutch in his 1931 Model A with a 3spd. Thats why I won't drive it. While my car is a stick, I don't think I could get used to double clutching. Plus, it only goes like 40mph tops...

[noahb270]

Re: double clutch

ok thanks everybody i was just wonderin cause ive heard that b4 but thanks!!

[black98V6]

Re: double clutch

Don't you have to double clutch in Semi's and other larger trucks also? Because they don't use syncros?

they are synchronized but it's kind of a different system than we use in cars, bigger gears and stuff like that make the meshing process a little trickier. If you don't shift quick enough you have to double clutch when at a standstill after that if you know what you are doing you don't "HAVE" to use the clutch at all because of the way the tranny is synchronized but some folks recommend using the clutch every time you shift to make things easier on the whole driveline others say not to use the clutch because it's just there for starting out in first.

[bah]

Re: double clutch

they are synchronized but it's kind of a different system than we use in cars, bigger gears and stuff like that make the meshing process a little trickier. If you don't shift quick enough you have to double clutch when at a standstill after that if you know what you are doing you don't "HAVE" to use the clutch at all because of the way the tranny is synchronized but some folks recommend using the clutch every time you shift to make things easier on the whole driveline others say not to use the clutch because it's just there for starting out in first.

yeah, a family friend has a trucking company, i dont think he uses the clutches for anything besides starting in first, my step dad had a sonoma that you could shift without the clutch without grinding also

[nikon]

Re: double clutch

yeah, a family friend has a trucking company, i dont think he uses the clutches for anything besides starting in first, my step dad had a sonoma that you could shift without the clutch without grinding also

ditto, your wasting your strength using the clutch after you got going...the only thing that is a little more tricky about a big rig is a dual gear axle....depending on the size or your load you, start in low first shift to neutral activate the 2nd gear set in the rear end, then back into first...same goes for 2nd and so on....but, thats usally a pretty heavy load if your driving like that....yes I've driven a couple 18wheelers before.

[bah]

Re: double clutch

yeah, dual speed transaxles are a pita, most of the time you can just leave them in high though, unless you have a huge load like you said

[keithert]

Re: double clutch

And double-clutching? It's like granny shifting except that you actually let the clutch out when you're in neutral, bring up the engine RPMs again, then push in the clutch and go into the next gear. And you do it all VERY fast. This was especially necessary on older cars before synchro gears smoothed the processes of changing gears in the gearbox. It is also a way to avoid grinding gears on transmissions that have been damaged by powershifting too much.

In my Nissan NX2000 I have to double clutch fifth or else it will grind. Those tranny have a reputation for loosing fifth gear.

[02PewterBird]

Re: double clutch

yeah, dual speed transaxles are a pita, most of the time you can just leave them in high though, unless you have a huge load like you said

Yeah, my dad used to have a 1979 Chevy C70 that he bought new that sounded incredibly complicated to drive. My uncle bought it when I was really young, but I haven't ridden in it since I learned how to drive stick and it might be easier now.

The 366 gas motor in that thing is a rock though. It still runs, and has to have way over a million miles on it by now.