Understanding downshifting

Discussion in 'Questions From New Drivers' started by Mr. EastCoast, Nov 2, 2020.

  1. Mr. EastCoast

    Mr. EastCoast Light Load Member

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    When I downshift I look at my MPH. Doesn’t the speed have to match with the gear I am trying to go in? My instructor told me to look at my RPMs only. Can you guys help me understand this please.
     
  2. Hegemeister

    Hegemeister Road Train Member

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    I use RPM up shifting and MPH down shifting.
    Many "instuctors" aren't worth a hoot.
     
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  3. Mr. EastCoast

    Mr. EastCoast Light Load Member

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    I was doing the same thing! He told me that only people who been driving for a long time can really do that. I’m still a rookie so I’m trying to figure this out. I can upshift without a problem. I can also downshift but he says I slow down to much. For example let’s say I am in 8th gear and I gotta downshift to 7th, I’ll slowdown and let the mph drop to 25 or atleast close to it and go to 7th
     
  4. shatteredsquare

    shatteredsquare Road Train Member

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    each gear has a MPH that it tops out at, if you're going 55 and try to stick it in 5th, it won't go in, the engine can't spin fast enough for that gear.

    I got taught to quick add the numbers of the MPH for an idea of what gear to shoot for (in a 10 speed) if i'm bringing it down off the freeway...

    35mph = 8 = 8th gear
    25mph = 7 = 7th gear
    15mph = 6 = 6th gear

    if your truck isn't RPM limited and you can take it up past 1500rpm, you can make a note of each gear to see how much MPH it stops at at 2000rpm, then you know if you're anywhere below that speed, you can grab that gear and it will go in
     
  5. Rideandrepair

    Rideandrepair Road Train Member

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    Pay attention to RPMs while upshifting, note the amount the rpm changes between gears. When downshifting, rev it up the same amount, works both ways. On a 10 spd for instance,lug it down to say 1100, then take it out of gear, and rev it up to around 1450-1500, and drop it in the next lower gear. Roughly speaking. Exact RPMs depends on the spread between gears. It helps to listen to the engine revving. Soon you’ll get the hang of it and be able to shift by ear,
     
  6. Brettj3876

    Brettj3876 Road Train Member

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    You in a 10 speed? 400 rpm between gears. Look at the tach not the Speedo. When on the low side your speed might drop faster so sometimes it's not gonna be exactly 400
     
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  7. LameMule

    LameMule Road Train Member

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    Use your ears.
     
  8. AModelCat

    AModelCat Road Train Member

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    I never look at speed. When I hit 1600-1700 I upshift, when I get down to 1100-1200 I downshift.
     
  9. Mr. EastCoast

    Mr. EastCoast Light Load Member

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    Yeahhhh 10 speed
     
  10. Dave1837

    Dave1837 Road Train Member

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    I use RPMs. Upshifting it's out at 1,600, in at 1,200. I run the engine brake down to 1,200 and rev to 16 to downshift. Of course every engine/trans pair reacts differently, you just have to learn your truck. Research the torque/HP curves of your engine and find the happy medium between both to figure out your best shift point
     
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