double clutching

[treemandan]

I just heard yet another version of what this is:

When you go from 1st right into 3rd. well now I am really confused. I will just stick to single clutching.

 

[TimberMcPherson]

I must be missing something

Double clutching used to the only way to go through a non syncromesh gearbox or heavy gearbox without being a throttle magician or grinding the box.

 

[Toddppm]

and that way would be?

Never was clear on this either.......

 

[Sc0]

Normal shifting would consist of pushing the clutch in, changing gears, then releasing the clutch.

Double Clutching would be pressing in the clutch, releasing it in neutral, then pressing down on the clutch again and then shifting to the next gear.

 

[Ekka]

Double Clutching would be pressing in the clutch, releasing it in neutral, then pressing down on the clutch again and then shifting to the next gear.

Hmmm, I disagree, the whole concept of double clutching is to get the gear box spinning at approximately the same RPM's as the engine for the next gear, hence the throttle blip when in neutral, so you sentence should read ....

Double Clutching would be pressing in the clutch, releasing it in neutral, blipping the throttle, then pressing down on the clutch again and then shifting to the next gear.

Try it, you'll see what I mean, get that next gear spinning at the right RPM and then get mesh not mash.

 

[ozzy42]

Hmmm, I disagree, the whole concept of double clutching is to get the gear box spinning at approximately the same RPM's as the engine for the next gear, hence the throttle blip when in neutral, so you sentence should read ....

Double Clutching would be pressing in the clutch, releasing it in neutral, blipping the throttle, then pressing down on the clutch again and then shifting to the next gear.

Try it, you'll see what I mean, get that next gear spinning at the right RPM and then get mesh not mash.

You are right about getting the engine and trans speeds to match.

You are very close except you only need to blip the throttle when downshifting,so the engine rpm meets the rpm it will be at when you grab the lower gear.
When upshifting ,you are actually waiting for the engine rpm to come down [usually about 400-500rpm less than ]what you ran the gear up to.If you hear a throttle blip while upshifting,it is because they missed the gear by a second or 2.

If you wound a gear up to 1600rpm ,you go in the next gear when the engine drops to 1200rpm.

Down shift is the opposite ;slow down the truck until you reach 1200rpm,clutch,rev motor to 1600 rpm,clutch,engage lower gear.
The #s I used are apr. not exact,as all trucks are a bit different.

 

[LTREES]

Normal shifting would consist of pushing the clutch in, changing gears, then releasing the clutch.

Double Clutching would be pressing in the clutch, releasing it in neutral, then pressing down on the clutch again and then shifting to the next gear.

That is correct.

Double Clutching would be pressing in the clutch, releasing it in neutral, blipping the throttle, then pressing down on the clutch again and then shifting to the next gear.

You do not BLIP the throttle.(unless you want to turn some heads, and then you need the proper set up) you want to get the rpms up if you are down shifting only to match the speed of that gear that you are going to. You double clutch to allow the rpms to lower cause people don't take the time to wait for the proper time to engage the next gear. Todays trannys allow you to shift right away, but listen to the engine's rpms shoot down to the level it should be when they depress the clutch. It takes a good driver to properly run an old gear box. my $.02

LT...

 

[ozzy42]

1 other thing

When double clutching,you do not deep clutch as you would when engaging a gear from a dead stop.
You just want to press it in far enough to brake the torque against the tranny.
A good practice is to put slight pressure[pulling it in the direction you will be going to use ] on the gears shifter just before you let off the throttle,and then you will notice it come out of gear with very little clutch pedal movement,and the same pedal travel should be used on your 2nd clutch.This is usually about 1/2 way down,and in time you will get a better feel of the tranny,and eventually stop using the clutch pedal for shifting.

One of those deals where "less is more"

 

[KD57]

I've hired many drivers over the years, and have only had 2 that was good enough to shift w/o using the clutch, like Oz sd., once you get a feel for it, it's fairly easy.

 

[gr8scott72]

1 other thing

When double clutching,you do not deep clutch as you would when engaging a gear from a dead stop.
You just want to press it in far enough to brake the torque against the tranny.
A good practice is to put slight pressure[pulling it in the direction you will be going to use ] on the gears shifter just before you let off the throttle,and then you will notice it come out of gear with very little clutch pedal movement,and the same pedal travel should be used on your 2nd clutch.This is usually about 1/2 way down,and in time you will get a better feel of the tranny,and eventually stop using the clutch pedal for shifting.

One of those deals where "less is more"

Then you can add heal-and-toe brake/throttle to the double clutching so you can not only rev match the gears as you downshift but you can do so while you are braking. Both of my last VWs were very fun to do this in. I had a 95 GTI VR6 and a 2000 Golf 1.8 turbo both with 5 speeds.

 

[BlackenedTimber]

Then you can add heal-and-toe brake/throttle to the double clutching so you can not only rev match the gears as you downshift but you can do so while you are braking. Both of my last VWs were very fun to do this in. I had a 95 GTI VR6 and a 2000 Golf 1.8 turbo both with 5 speeds.

try going heel-toe in a Peterbilt 379 with a cat 600 and 18-speed Eaton... thats fun

 

[TDunk]

I just find it alot easier to just not use the clutch.

 

[clutch25]

Driving heavy truck, you rarely use the clutch...only to stop and go...unless you realy screw up (like I do all the time).

All of my vehicles are manual trannies...and I rarely use the clutch on them either.

 

[gink595]

The way I was taught is you really don't need to touch the clutch except when taking off and stopping. The rest is learning the truck and where it like to shift at. If you get to high or low in the Rpm than you blip it to get them to mesh. A good driver can up shift and downshift with out ever touching the clutch, grind em till you find em.

 

[clutch25]

The way I was taught is you really don't need to touch the clutch except when taking off and stopping. The rest is learning the truck and where it like to shift at. If you get to high or low in the Rpm than you blip it to get them to mesh. A good driver can up shift and downshift with out ever touching the clutch, grind em till you find em.

True that!

 

[mic687]

On some of the old spicer trans you almost needed to double clutch they suck. Fuller eaton float them gears all the way. I was taught to double clutch when I first started driving it didn't take long for me to learn to float shift (shift without) the clutch. Once you learn you will never go back. Nothing like a lite load and 450+ supercharged two stroke horse power zipping through 13 speeds.

 

[TDunk]

I knew a guy that had a tilt bed with a 6 or 7 speed spicer. Always having tranny probs. since it was new. Turns out he wasn't using the clutch and it was a synchronized tranny. Bad idea.

 

[smilin possum]

What would ya'll do with a one stack Mack with a picture window in the back and a 237 Maxidine with a duplex three stick.

 

[mic687]

Alot of the Internationals running a dt466 motor are coupled to a spicer 7speed you can single clutch those but I always double clutch they rev real high and loose revs real fast when the clutch is depressed. I never cared for the spicers that much a Fuller is so much smoother. I ran a Mack CH with a 350 and a Fuller super ten speed a few years back pretty slick trans.

 

[mic687]

What would ya'll do with a one stack Mack with a picture window in the back and a 237 Maxidine with a duplex three stick.

Sell it and get something I could shift LOL. I have never run a even a twin stick 5 and 4 but I would like to give it a shot.