Humbled By Shifting.... :)

Ken suggested "1 one-thousand 2 one-thousand" = that's two seconds. Way to much time in traffic. Learn with it on the driving/shifting range, but if you say out loud "bop - bop", that's the timing you should aim for.

I think you guys are both right because of progressive shifting. It's bop-bop in the lower gears but one-one-thousand two-one-thousand in the higher gears where you have to wait longer for the revs to drop.

Ken suggested "1 one-thousand 2 one-thousand" = that's two seconds. Way to much time in traffic. Learn with it on the driving/shifting range, but if you say out loud "bop - bop", that's the timing you should aim for.

I think you guys are both right because of progressive shifting. It's bop-bop in the lower gears but one-one-thousand two-one-thousand in the higher gears where you have to wait longer for the revs to drop.

Brett, one thing I think is missing in learning the double clutch: your truck is slowing down while the driver is shifting. You're right about the timing (and after a bit the action becomes internal), but when you get "lost" in neutral looking for the right gear slot, the truck slows down enough you might have to go back to the gear you just left.

BTW, I prefer to double clutch in the lower gears, but once I flip the selector, I glide. There's too much force going through the transmission in the lower gears, so clutching seems to make it easier there.

BTW, I prefer to double clutch in the lower gears, but once I flip the selector, I glide. There's too much force going through the transmission in the lower gears, so clutching seems to make it easier there.

Warning: newbies ignore what I'm about to say. You won't be able to make sense out of it until you're out there floating gears for a little while.

It's a little more difficult getting the truck out of gear in the lower gears if you're floating because the truck doesn't have as much momentum. When you're in 3rd or 4th getting started and you let off the gas, the truck is rolling so slow it's tricky to get that little bit of momentum to push against the transmission and take the tension off the gears so you can pop it out of gear.

Have you noticed it's also easier to float gears when you're loaded heavy than when you're empty? Same reason. The momentum from all that weight in the trailer helps to 'push against the transmission' or push the truck forward after you let off the gas so the tension comes off the gears and you can pop it into neutral.

Overall it's easier to float gears with more momentum, whether that means the truck is rolling faster or it has more weight behind it.

Interestingly enough if you have too much momentum, like when you're loaded heavy and rolling down a hill, it's again tricky to get it out of gear because the momentum starts pushing too hard too quickly against the transmission, making it tough to pop it into neutral.

The bottom line is that your timing has to be precise. By the time you let off the gas you have to already have tension pulling that shifter out of gear and sometimes you have to give it a quick 'pop' to get it out of gear and into neutral. When you're in a situation that makes it more difficult to float gears you have to accelerate hard and instantly let off the gas while popping it quickly out of gear. Don't ease onto the accelerator and ease off the it or you won't release the tension in the gears, allowing you to pop it into neutral. You have to be more aggressive with the throttle and the shifter.

I actually had the same exact problem a few months ago while learning, I quickly figured out that the clutch pedal was doing NOTHING to help me shift and actually hindering the process because I was pushing it all the way down. If your instructor will let you, learn to float the gears first, that helped me a ton. I can actually float the gears in my subaru now.

I see lots of references to not having to double clutch after the test. What's the logic for requiring double clutching during the test?

I see lots of references to not having to double clutch after the test. What's the logic for requiring double clutching during the test?

Rather than (ahem) re-inventing the wheel, I copied this from Wikipedia:

The purpose of the double-clutch technique is to aid in matching the rotational speed of the input shaft being driven by the engine to the rotational speed of the gear the driver wishes to select (directly connected to rotating wheels). When the speeds are matched, the gear will engage smoothly and no clutch is required. If the speeds are not matched, the dog teeth on the collar will "clash" or grate as they attempt to fit into the holes on the desired gear. A modern synchromesh gearbox accomplishes this synchronization more efficiently. However, when the engine speed is significantly different from the transmission speed, the desired gear can often not be engaged even in a fully synchronized gearbox. An example is trying to shift into a gear while travelling outside the gear's speed or directional range, such as accidentally into 1st from near the top of 2nd, or intentionally from reverse to a forward gear whilst still moving at speed.

Double clutching, although time consuming, eases gear selection when an extended delay or variance exists between engine and transmission speeds.

Although double clutching is a testing requirement when obtaining a commercial driver's license, most experienced truckers learn to shift gears without using the clutch. This is known as float gears , which thus eliminates the clutch except during starting and stopping. Skip shifting is when a gear is left out, usually on an upshift, for example shifting 2-4-6 while accelerating with the help of gravity down a hill. This technique saves unnecessary shifting work and saves fuel.

Conversely, in order to shift down, engine RPM must be increased while the gearbox is in neutral and the clutch is engaged. This requires the driver to slow the vehicle sufficiently, shift into neutral, apply throttle to bring the RPM up to a suitable speed, and finally shift into gear. This operation can be very difficult to master, as it requires the driver to gauge the speed of the vehicle and throttle to the intended gear accurately; vehicle weight and road gradient are important factors as they influence the vehicle's acceleration or deceleration during the shift. Double clutching is when the clutch pedal is depressed while shifting to neutral to match engine speed to the intended gear and vehicle speed, and again depressed for shifting into gear.

Rather than (ahem) re-inventing the wheel, I copied this from Wikipedia:

LOL, thanks, I'd read the definition (google is my BFF!), but I do appreciate the response from one of my favorite posters as my first response! ;)

What I'm really asking is why it is required on the test when it appears it is rarely used by experienced drivers. The wikipedia article even says that, but still doesn't say why it's required on the test. I get that there are some things on tests that just aren't realistic in the real world and that's the nature of the best. However, I'm interested in the rationale behind making it a seemingly such important part of the test.

Shirley, who has permit in hand but 28 more days until class starts. tick tick tick tick...

What I'm really asking is why it is required on the test when it appears it is rarely used by experienced drivers

For one, the manufacturers of transmissions and drivetrain parts still recommend double-clutching. Also, at times you'll get the shifter "stuck" in a gear and it won't pop out without the clutch. For instance, you're rolling down a steep hill loaded heavy and you try to get it out of gear but you let the revs go so high that you're against the RPM governor. Normally you would just "kick" the throttle quick and pop it out of gear. But kicking the throttle doesn't do anything because of the RPM governor and the heavy weight is pushing hard against the gears so it won't pop out of gear. The only way to get it out of gear is to push in the clutch to release the pressure.

So they figure it's something you should learn how to do and once you get out there you can float gears if you like. But at least you'll know how to double clutch and you won't panic if you can't get it out of gear when floating gears.

Basically what I was going to say. It's required because you need to know how to do it, not because it's always necessary. I tend to double clutch more when downshifting, rarely when shifting up. But there will be times one needs to get it in gear and blipping the throttle either won't work or isn't practical for the situation.

Great answers and exactly what I was looking for! Thank you, all three of ya!