DOWN Shifting

For the same reason they put that light that tells some people to put on their seatbelt.

You do not need to use the clutch in an unsyncronized box for anything but wanting to stop power from flowing to the axles.

Using the clutch is the mark of an poorly skilled driver who does not know who to match road speed to crankshaft speed, automatically syncronizing the transmission shaft speeds naturally. The reason the synchro box was invented was to make an unskilled driver into a skilled one by engineering around his lack of skill.

Seasoned race car drivers actually remove the synchros from modern synchronized transmissions so that they can shift through the corners not using the rookie clutch. There are three pedals and a race car driver only has 2 feet.

 

Nice stereotype. Floating isn't feasible all of the time. Depending on the terrain and the weight of your load, it could be better to double-clutch.

 

While most seasoned drivers don't use the clutch, many companies require it. A new driver can do some damage without it too. Many companies won't pass you on the road test if you can't double-clutch.

I float gears myself. My advice to any new driver is learn how to double-clutch. When you're on your own learn how to float.

 

Double Clutching and Floating is both important to learn in my opinion.

Anyhow, I'm a new driver and signed on with a company who prefers floating. So I basically had to learn how to drive all over again and while doing it in a tanker. Floating up is pretty simple but floating down requires a little more practice. I spend half my driving on oilfield lease roads. So I would practice floating up and down on these roads....generally no higher than 6-7th gear. It.s been explained already but basically you jazz the throttle to get it into neutral and then jazz the throttle again to get it into a lower gear. Now depending on how quick you need to stop, you can either just let the vehicle slow down or ease into the brakes. Shifting is generally around 1000-1300 I believe but could be wrong.

 

Svoray, I too work in the Oilfield, and it seems most of the guys float. But I am more comfortable double clutching, especially when loaded. I can float up on nice smooth roads, but floating down can be a pain for me. Now when I'm creeping along a lease road at 25mph I can float up or down pretty well when I hit a fairly smooth spot in the road. And I too am usually in 6th or 7th the whole time; that seems like a decent power range for that speed and the load of water.

I did have an issue the other day where I HAD to float because something gave out and the clutch pedal went to the floor. I was able to get it out of gear and stopped, but the road I was on was fairly narrow and the truck needed to get out of the way. I learned that you can start a fully loaded truck in first gear. Turned truck off, let the brakes off to get the truck to move a hair to get it to go into 1st, kept light pressure on the brakes and turned it over, let off brakes and started moving, and then floated up to 5th and got it parked at a oil rig off the main road a mile or so up the road.

 

Do they require a double-clutch on every shift, up and down?

 

wrong doesnt matter your skill every truck is different pal until you get used to a truck floating isnt gonna happen right outta the box, i just got a new cascadia and floating it is a chore at times particularly in the top gears. so im sticking to the clutch for now even tho im fully capable of floating.

 

I failed a road test due to this in the 70's. I had never had to do it. I hear some companies still do require it. I learned floating, but I'm very mechanical and could float every manual vehicle I drove before entering trucking.

IMHO, a new driver can do a lot more damage floating than clutching. It shouldn't matter to you because you have to manipulate the RPM's exactly the same regardless of method. Personally I don't think you'll ever get faulted for double-clutching on a road test but could for floating.


EDIT: These are just my opinions. I would hope the schools would know how to train for a successful hire. Maybe Rerun will come along and answer. I think he is still working at a school.

 

I've drivin 2 trucks with the eaton 10 speed and can offer you some advice. Depending on the truck/engine the sweet spots are a little different but close. the truck I'm driving now is a 2010 international prostar with a maxxforce. its up-shifting sweet spot is 1500RPM's And its downshifting sweet spot is somewhere between 1000 1100 RPM's pretty much once you get into that downshifting sweet spot hit the clutch take it out of gear bump the fuel to between 1000 and 1500 RPM's and make the shift. Another good way is to watch your speed. For instance 9th gear in my truck will only get me as high as 50MPH in my truck. so when I'm in 10th and want to goto 9th i wait until my speed is between 45-50MPH and than i know I'm good to downshift... practice makes perfect with downshifting. I got it pretty quickly (within my 1st session in the truck) when training for my CDL I was rusty at it but got it 90% of the time.

 

Unless you have one of those fancy volvo transmissions or intimately know your truck yes. sometimes you'll get it exactley in the right spot where one shift is all you'll require but its luck every time I hit it and I dont like it when i do because i shake the hell out of my truck when it happens from letting back off the clutch and giving it a little gas.