Rookie question about floating gears
Afternoon all another question from the newbie. At school we had to learn to shift gears via doubleclutching and wouldnt let us learn to float. We were given 1300 rpms for low gears and 1600 rpms for high gears and down to 1000 rpms to downshift. What is the difference via floating ? Do you get to proper rpm for gear than lift on the throttle to push to gear than back on the throttle ? Any help is greatly apprecited I head to orientation in a little over 2 weeks.
At school we had to learn to shift gears via doubleclutching and wouldnt let us learn to float. We were given 1300 rpms for low gears and 1600 rpms for high gears and down to 1000 rpms to downshift. What is the difference via floating ?
None (for me, at least)
Do you get to proper rpm for gear than lift on the throttle to push to gear than back on the throttle ?
Yeah, that's about right.
The actual rpm level is dependent on your engine's operating range. For me, I have a 15-litre Cat, with a 9 speed 'top-two' transmission (8th and 9th are automatic, the rest, manual). For most of the high range, I upshift at 1500 on level ground. However, it's best to adjust this for uphills, downhills, and whatever weight you're pulling. It will become apparent very quickly as to how much juice you need to give it before you upshift, once you start hauling freight. This is why I'll sometimes stretch it out to 1600rpm on a steep uphill with a heavy load, and why I'll sometimes shift up at 13-1400rpm in the high range going downhill with the same load (if I'm in a safe spot to upshift, that is).
This also depends on the transmission you'll be using (although most companies use 9- or 10-speeds, but TMC has been known to use 13's and Keen 18's), but you'll get the hang of it in due time.
There is a certain RPM that you can take the truck out of gear without using the clutch. Likewise, there is a certain RPM that you can put the truck back into gear without using the clutch. That is what "floating" the gears is. Each truck is different at what speeds and rpm's it will do it at, and the only thing that will teach you how to do it is time and practice.
Originally Posted by Flyerfan4life
You don't want to be attempting to learn this heading into orientation. Company's don't exactly like you "floating" gears as it is so no need to be showing them that your learning to do it.
oThanks for the info folks. I will stick with doubleclutching through the roadtest etc, I am just curious to continue learning as much as possible. My instructors at school did say most truckers float the gears. I have the internet on my phone so I can take the board with me when I HIT THE ROAD.
I've learned to float on my own. I'm still learning, and i can't float like vets who has been driving for years, BUT i've found that floating is much easier than double clutching...and faster.
In order to HAVE pride, you must first TAKE pride.
I was thinking that floating may help get you rolling through a light or intersection faster than doubleclutching especially from a dead stop. Hopefully I can pick it up like you. I did pretty good at doubleclutching in school and was probably the only one in my class that wouldnt give you whiplash.
Originally Posted by Kevin0915
It's actually quite easy...
Once you get the hang of WHERE the engine WANTS another gear (either up or down) WITH the clutch - it works EXACTLY THE SAME - except WITHOUT the clutch.
Fr'example - you usually drop 300 RPMS's per gear on an UPSHIFT (and likewise on a down). So when you clutch in and shift to N, then clutch in again and upshift - you usually "lose" 300 rpm in the next gear up. If your TIMING is right, you will hit that next gear up, as the revs are DROPPING from when you clutched in to get to N. So, if your upshift point is 1,600 - by the time your rev's drop to around 1,300 - you should be clutching back in and shifting into the next gear. Let the rev's DROP too much and GRIND - likewise, don't let them drop ENOUGH and GRIND.
The "sweet spot" is all in the timing. When you're getting it right with the clutch, you go from gear to gear, seemingly with minimal effort on the stick - kinda drops right in. When you've got that timing down, and know the "sweet spot" for your engine/tranny combo - just shift the SAME - but WITHOUT THE CLUTCH. Hit 1,600, let of the fuel pedal sharply and pull (or push) into neutral - as the revs drop down from 1,600 - start pushing (gently) towards your next gear - when the RPMS/Road Speed match up, it'll just drop right in - then back into the fuel.
Downshifts take a little more finesse (and alot more practice). You need to blip the throttle slightly to get to neutral, then blip 3-400 rpms UP for 1 gear and 7-800 for 2. So if your downshift point is 1,000 - small blip, move to N - blip up to 1,400 and you should drop into the next gear down as the RPM's fall past the 1,300 mark. Again - all in the timing. If you can get it proficiently without GRINDING with the clutch - then it's only a matter of a little practice to float.
By the end of my 9 week course - I could float up and down on every truck in the school - 10's, super 10's, 13's - from the 85 KW Cabovers, to the 2000 Century's (old crap we had - county school) and the good old 78 Longnose Pete 9 speed (my favorite, I got attached to that good old girl, floated like buttah)...
Once you get it down - you'll only use the clutch to launch, and when you occasionally lose track of what frikkin gear you're in, and have to hunt for the right one (GROAN)...
Best of luck...
Each gear has both a ground speed range & a proper engine RPM range before you can "float" the gears. "Floating" the gears means for an 1/2 second or so- you are n neutral while you "float" between the gears.
Like the above person pointed out-- you don't want to be doing this during a "road test" as a newbie- inexperienced driver. When you're not n gear-- you're not in CONTROL. The safety man that's hiring you.. isn't going to be impressed with you rolling 3 truck lengths or so in neutral while trying to find the "sweet spot" rpm to make it all sync.
Stick to "short cuts" that work. Starting in 3rd. Rolling up to the stop n gear with the clutch depressed- instead of trying to down shift through all the gears and missing any of them. Don't shift in a turn. Don't over rev the rpm's during shifting.
You can learn to "float" and skip shift later- while you're making $$$$.
It took me about a month or two to learn how to float on my own.. I just kept practicing and practicing when i ran night loads and i was out on the road by myself.. Now i'm smooth at times but sometimes i can scrap a few when i'm in a rush!!
But if i was you when you get out on your own just practice then and then it will become natural too you!!
Thanks a bunch folks ! I am really learning alot from this site and its members. What I typically do when downshifting as a newbie I try and atleast get down to 7th gear stop flip the switch to low go to neutral than back to 7th which now will be 2nd and start from there again. What is the difference between a normal 10 speed and a super 10 I dont think I have driven super 10 yet.
"Normal" 10 has 5 low, flip the switch 5 high. Super 10 - no low/high switch - split shift. 1/2 in one position - start out in 1, hit the switch and let off the fuel (or stab the clutch to release torque) the tranny shifts to 2 (without moving the stick). Move the switch back, double clutch (or float) into 3, move switch break torque and it shifts into 4. You get 10 gears with 1/2 the movement of the stick - as each physical shift has 2 gears.
Originally Posted by Flyerfan4life
They're fun to drive, less tiring (less stick movement), easy to get confused and lose track of where the hell yer at gear-wise. My instructor called it "the thinking mans" transmission. You can do a 2 gear downshift with one move of the stick (don't forget to rev). Think of the switch as an odd/even switch and it's easier to figure where you're at. Only 4 guys in my class (of 12) even felt like trying it out - the rest had enough problems shifting ANY transmission. You don't see them on new(er) trucks, I had a lot of fun driving it.
As others mentioned, you don't want to be floating for your road tests (state or company). Just shift the truck with the clutch, be smooth, and don't coast. Turns (at least where I went to school) have to be done in low range. If you're in 7th, drop down to 7-800, clutch into N, clutch out, rev up to 1,600, clutch in and "loop" into 5th (don't forget the low/high switch). You can't ALWAYS get a red light at a turn (much as we like to PRAY for them in school during road testing). You MUST develop the skills to keep the truck in the PROPER GEAR for your road speed/RPM. Lugging/over-revving is a NO-NO.
Last edited by SickRick; 08-13-2009 at 06:02 AM.
One of the drawbacks of the "Stupid 10" transmission is that the RPM drop when you are splitting your gear is really long. It's quite easy to flip the switch, let off the throttle, and then hit the throttle prematurely before it has grabbed the gear. When splitting gears on a Super 10, I always popped the shifter out of gear, and immediately popped it back in. Essentially, I was floating the split gear the same way I'd float the standard gear change. It caused the RPM's to drop much quicker.
Originally Posted by SickRick
The biggest thing I noticed about the Super 10 is that I got fantastic fuel mileage out of them. The guy I drove for who had one, had 13 speeds in the rest of the fleet. I easily gained 1 mpg driving the Super 10 truck over the 13 speed truck. At one point, I was averaging 7.7 mpg out of it, pulling a hopper bottom (80,000 on virtually every load). It's a lot harder to gun the truck with that transmission, but it is much less forgiving if you hit the wrong gear.
Thanks Rick I had heard of a super 10 but had no idea what was different. I have no idea what type of tranny Covenant uses so I am unsure what to expect tranny wise there.
A few words of caution for shifting without the clutch... you don't want to be unwittingly wrecking things!
There isn't enough good info out there for a driver to learn the principals of clutch use.
Whether you use it or not, it all depends.
"Floating" or clutchless shifting, is too often a juvenile expression of manhood.
As in: "No real trucker would use the clutch" and all that tripe.
For a seasoned veteran of the road, driving a familiar piece fo equipment, it is a fatigue managment technique, for the novice or unfamiliar, it is damaging to the equipment.
If you haven't seen the insides of a truck transmission, make it your business to get someone in a reputable shop to show you how the pieces relate to one another when you change gears. Just walk in and ask some questions!
There are a lot of gear sets sliding on splined shafts that are easily damaged by the misapplication of throttle or shifter movement at the wrong time.
If you feel it rubbing, you are grinding pieces of metal against one another. The word "floating" itself suggests that somehow it's ok to wander the shifter around until it finds somewhere to go. Not so.
Think of it this way: The power of the engine is coupled to the weight of the moving vehicle via the clutch.
You disengage the connection in order to only have the spinning inertia of the gear sets chewing into one another, when you don't get the speeds of the two sets matched correctly by your shift timing/engine rpm managment in the shift. They are intended to withstand that type of wear for many thousands of cycles.
If you leave the power of the engine and the weight of the vehicle connected by leaving the clutch engaged when you shift, then those two very significant forces get to meet against one another on the very tips of the splines or gear teeth, as the case may be, as you try to slide the gear set along that shaft with the shifter.... great if you have the two pieces spinning the same speed, disasterous if you get it wrong.
Any tranny shop will have a twisted shaft in the scrap bin to show you what happens to the splines, and gear sets with teeth chipped off. They'll also have evidence of what those broken teeth do to other parts if they don't fall directly into the pan.
You may have driven or heard of trucks that won't stay in gear? The edges of the gear sets and the splines are so worn down, they are rounded off and the gears won't even keep themselves together with the torque of the engine squeezing them. A truck that won't shift into one or more gear positions? The splines are twisted, the gear sets won't slide along the shaft.
A correction: there is no "time saved" by shifting without the clutch. You have to wait for the engine speed to either slow down or speed up to match the spinning speed of the other gear set you are trying to engage, which has nothing to do with pumping the clutch.
If it is "faster", then your shifting and clutch work has been too slow, and you are putting wear on the clutch with every shift by bumping the engine rpm back up as it has fallen past the engagement speed.
A non synchro heavy duty transmission and its attached engine will only shift at one speed, and that is the speed at which the engine RPM falls enough RPM to match the next gear, or the speed at which you ask it to rise via the throttle. You can't change that. (well, there is the jake switch, but that's another post!)
The smallest wear is of critical importance to an owner operator, as he/she who drives furthest with the least expence wins. Taking out some gears in your own truck? Financial ruin!
I guess a company driver can afford to experiement earlier with his employer's truck.
Ok, so you want to learn the fatigue management technique?
As noted above, get good with the clutch first, every shift for many days, upshift and downshift, goes in without a snick or a grind, the tachometer NEVER bumps when the clutch is let up, you are matching every gear perfectly, every time, the clutch is enagaging and disengaging parts that are rotating at the same speeds, not having to force the egnine to the matching rpm.
On a roadtest to drive my truck, I want to see you shift both ways, so I know you can properly match engine rpm to road speed. But I also like to see a mature and responsible driver use the clutch on those quirky shifts, often the range shift, sometimes a wider gear, the shifts that don't time well, when it would be easier on the gear sets to use the clutch. And I expect that driver to use the clutch for the first few times through the box in order to feel the truck out. Clutchless shifting in a new-to-you truck? That risks communicating the wrong thing to your evaluator. Ignorance, disregard for someone else's property, carelessness, cowboy, all of which probably aren't the impression you are trying to make.
Show an employer you are smart, responsible, and that you know how to care for the equipment.
Lightblue Freightshaker :thumbsup:
I havent seen the internals of a truck tranny yet. I have worked with a freind and helped him change the clutch and complete rear end of his dump truck. My past career I have been a Prevost motorcoach service tech so I have some experience working on diesel engines and repairing air brake fittings and the like.
Last edited by Flyerfan4life; 08-13-2009 at 08:00 AM.
Every truck and transmission is different and each has their own sweet spot in RPM's when floating. Everyone has their idea and method and you'll find what works for you. I know guys that have been driving for years and still doubleclutch. I would suggest master doubleclutching and just driving skill in general before you attempt to float gears. Most drive tests you will take especially at the big companies will have you doubleclutching so don't forget it. Plus you will hear mechanics tell you two different stories I've had ones tell me doubleclutching saves transmissions and other tell me it tears them up, I guess it depends on who you ask. As for me personally I float because that works best with me. If you get s stiff transmission and need to downshift in a low gear sometimes you will have to use the clutch because sometimes those gears get a little stuck (not literally). Down the road you'll find out what works with you best, good luck.
Last edited by 1TruckDrivinSunUvAGun; 08-13-2009 at 08:50 AM.
especially when you get all upset at a shipper and curb a trailer tire, blow it and damage the rim. ;-)
Originally Posted by Hawkjr
In order to HAVE pride, you must first TAKE pride.
Once you learn how to match engine speed and road speed you very quickly learn how to float ...Kevin saying he's not that good at floating yet means he's also not learned how to match engine/road speed very well yet either ...WINK
So THAT's what's wrong with my Freightshaker...
Originally Posted by LBF
Don't be surprised if that happens to you with your truck. With big companies, one often inherits another's problems...