Downshifting, how can I learn how to do it?

Discussion in 'Questions From New Drivers' started by TravR1, Dec 21, 2021.

  1. TravR1

    TravR1 Road Train Member

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    One thing I noticed on the second part of my drive when I took an exit, I got downshifted OK. Then when I came up to the connecting freeway I was stuck in 8th gear.

    My speed was good, and ready for the shift up. But my RPMs were stuck too high and it wouldn't come down. I wasn't on the throttle. It's like it just froze there.

    I eventually got it when the road flattened out. But when the RPMs get stuck high, how do you bring that down? I tried to brake a little even though I was already going too slow but it stayed high at about 1800 would be my guess and it wouldn't take 9th.
     
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  3. Dino soar

    Dino soar Road Train Member

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    I would suggest it's easiest if you can find a flat road and practice your shifting a bit there.

    I would also suggest watching your RPM gauge and really listening to the sound of the engine. On the flat road let's say that you shift at 1600 and the engine drops down to 1200. Now right away from there if you shift back into the gear you just came out of again watch your tach and listen to the sound of the engine. It should go back into the lower gear at about 1600. They are the exact same process only reversed.

    The flat route is good to practice on but it becomes a little more tricky when you are loaded and if you are going up hill or downhill.

    If you are loaded going up hill and the engine RPMs are coming down you have to shift at a little bit higher RPM. So in the example above you down shifted at 1200 rpms. I don't know what truck you're in or how the RPMs work on that but for the sake of the example let's say that if you down shift at 1200 rpm's that puts you at about 16 and that's where the power of the truck is. So 1200 would be the time to downshift- on a flat road.

    Now as you climb the hill the speed of the truck is slowing down. That's different than it was on the flat road. So if you're loaded heavily and the truck is beginning to slow down you have to down shift at a higher rpm. Because the object is to match the engine speed with the correct gear for the road speed because the truck is slowing down you need to start earlier at a higher rpm.

    So in this case let's say that you begin to downshift at 1400. This gives you more time to get the truck into gear.. If you are late when you try to downshift you'll never catch the next year you'll actually have to skip down to a lower gear and you really have to know where you are to find the right gear at that point. The faster the truck is slowing down the earlier you need to shift.

    So if you're climbing a hill and the truck is slowing down, downshift at a higher RPM.

    Now going downhill is the opposite. If you're going to slow down and down shift you should try to slow down to an even lower RPM because the truck is going to pick up speed. So if 1200 RPMs is where you normally downshift on flat road, going down the hill you should begin your downshift let's say at 1000 RPM.

    You have to know what your RPMs are and where the power is for your truck so the actual RPMs will vary according to what engine you have, but that's the idea.
     
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  4. mile marker 27

    mile marker 27 Heavy Load Member

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    I float the gears up and down all the time but,.......there’s occasions, as you stated “hung” that I’ll quickly and gently tap the clutch. You gotta be quick and have your foot on the throttle and depending situation, maybe the brake. DOT would flame me for this but in time you’ll be driving it by ear and feel. That’s how you drive a truck,.....with all your senses. Smell antifreeze, feel a wheel bearing, hear a u-joint, watch your mirrors and gauges. When I drive, it’s according to the particular road, the load and traffic.
     
  5. goga

    goga Heavy Load Member

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    I would repeat the post of 062 with "watch the speed and RPMs" with a bit of detail. LEARN the RPMs on each speed, in my case on 10 speed it is a 500 drop. Meaning, I run the engine ALWAYS between 1800 and 1300 RPMs, up or down. If I'm pulling up hill, or stopping and need to shift, I wait till 1300RPMs come up, then release the gear, rave the engine till 1800 and stik it in.
     
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  6. goga

    goga Heavy Load Member

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    Amen to every word. It becomes mechanical to the body with the time.
     
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  7. TripleSix

    TripleSix God of Roads

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    The spread.
    The majority of states will give you 34k on drives and 40k on the spread, BUT still can’t gross more than 80k. Basically because they are spread so far apart, they get the same rating as a single axle, 20k each.

    EDIT…

    BTW, the lower the rpm, the easier it is to downshift. 1100-1200, quick blip of the throttle and you’re in. The higher the starting rpm, the higher the engine has to rev.
     
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  8. TravR1

    TravR1 Road Train Member

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    I think that's what happened today. I'm on flat land today mostly. But I had an upgrade I had to downshift and it was smooth. Popped right in. Right at about 48 mph or so, just pushed it straight up.

    Then I drove into a weigh station and broke the truck. Right under dot nose. Fortunately they didn't seem to care. They weighed me and sent me on down the road.
     
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  9. TravR1

    TravR1 Road Train Member

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    That makes a little bit of sense to me. Thanks.

    As far as downshifting going down hill, I was told I need to find my gear before I begin going down the hill, then just leave it alone.

    So I was going through that in my head. Trucks seem to like slingshotting them selves down those hills. Lol very few trucks slow down before the hill.

    I'm talking about those major passes. The hills I've been doing so far, I just took them in 10th gear and I was fine.

    So if I wanted to go down Monteagle at 45 mph, then I would probably want to find 7th gear before I descend. Is that what you would do?
     
  10. Dino soar

    Dino soar Road Train Member

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    On any real descent you want to find your gear before you go down. Some places have a pull off that you actually stop and then you start off again to make sure that you're in the right gear. Trying to downshift on a steep hill is really dangerous because if you get caught in neutral you are effed.

    But if you are coming down a hill that isn't a giant mountain pass, if it's just some kind of a hill but the truck will pick up speed as you downshift and let's say you're coming up to a light as you go down the hill but you have no danger of losing your brakes, then you have to slow down even further like I said to a 1000 RPMs or whatever it is to make the downshift. And if you really want to be tricky you can use your left foot for the brakes and then use your right foot for the accelerator as you shift. That way the truck is not picking up speed as it goes down the hill as you shift. It gives you more control over things.

    And don't pay attention to what anyone else is doing. Do what you have to do to make sure that you are safe and you are in control of the truck you are in.

    The guys that you see flying down the hills are guys that have become more careless, or they're in a hurry or they travel that route so much they think they can fly because they know the road so well.

    If you know the road really well you may be able to go a little quicker but you have to be safe. Any mountain pass you have to take your time because because if there's a stranded vehicle or hazard in the road or patch of ice, whatever... You want to be safe and keep everyone around you safe.
     
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  11. ad356

    ad356 Road Train Member

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    practice, practice, practice. eventually it becomes almost 2nd nature and you barely think about it
     
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