Gear Ratios: Misinformation at its worst.

Discussion in 'Experienced Truckers' Advice' started by Hammer166, Apr 28, 2021.

  1. Hammer166

    Hammer166 Crusty Information Officer

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    I am well aware of what overdrive means, and I'm also well aware of the heat losses when using overdrive gear ratios. Those losses are the direct reason for the current direct-drive transmission fad, trying to squeeze every drop of fuel you can out of a drivetrain. Those losses are minimal, at worst a couple percentage points. Bruce made it sound like running an overdrive was just chopping your horsepower in half! Frankly from the driver's seat you would be hard-pressed to tell the difference between a direct drive setup and an overdrive setup, as the overall gearing from flywheel to wheel end is basically equivalent.

    The origin of double over goes back to the twin stick days, when the big steppers had both Transmissions turned around, hence double Overdrive. As I just pointed out a post or two ago, the first single stick double over had three overdrive ratios,yet was called specifically the 13 double over.

    And if I had to Hazard a guess, the most egregious misuse of double over, using it to describe a single overdrive transmission, most likely started as a genital measuring contest at the lunch counter.
     
    Last edited: Apr 30, 2021
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  3. jamespmack

    jamespmack Road Train Member

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    You guys are splitting frog hairs.

    Just like a guy jumping on me for calling Lo in a RTLO 1st gear.

    Its first gear in the box. 1-5, or Lo-4 on shift label.

    On a consumer point input shaft is turning same speed as engine. A rtlo has 2 overdrive ratios to be used coming out of the tail shaft. In theory yes it has a single overdrive gear in main box of a married transmission. 2 overdrives in separate divorced boxes accomplish the samething.

    Most guys don't have a simple clue how any of it works. Zero point in getting worked up about it.
     
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  4. REALITY098765

    REALITY098765 Road Train Member

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    agreed and overdrive doesn't have to be in the transmission either. So you could have an overdrive in the transmission and 1 outside on the driveshaft. that would be a double overdrive.

    IMO overdrive is the ratio between the crank and driveshaft. IOW the driveshaft is ''overdriven''.

    I guess from Bruce's perspective 20% over drive is double10% overdrive.

    I don't think anybody is getting worked up, We are just ''bench racing''.
     
  5. jamespmack

    jamespmack Road Train Member

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    Everyone communicates different.

    Bruce should have said "2 overdrive final ratios".
     
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  6. Magoo1968

    Magoo1968 Road Train Member

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    Almost Every driver on this site has driven a truck that when loaded to max on a hard pull you might be in 5 hi or lo .. put 2.64 in the back and now you’re in and out of the basement gears. Only way around that is to turn up power a bunch. A direct drive transmission has different ratios in it so it’s not a big issue .
     
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  7. Hammer166

    Hammer166 Crusty Information Officer

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    My issue is much less with calling a 13 or 18 a double over, then it is with him saying that modern 9 and 10 speeds are double over. That and he totally misrepresented the direct versus Overdrive. He wants to pretend to be the go to shop for diesel performance, but he might want to learn what the heck he's talkin about, and not spew the same thing I could hear sitting at the lunch counter or turning on Channel 19.
     
  8. Cat sdp

    Cat sdp . .

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    Is he still on the air....?
     
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  9. Hammer166

    Hammer166 Crusty Information Officer

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    Don't have a clue. I see his blog post gets reprinted in that moving out paper every month
     
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  10. jamespmack

    jamespmack Road Train Member

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    Oh I agree. They are direct, or overdrive.
     
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  11. Long FLD

    Long FLD Road Train Member

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    Every week (Tuesday maybe?) he’s on Rutherford’s show telling everyone to buy his fuel catalyst.
     
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