The "Sweet Spot" (best MPG)

Discussion in 'Experienced Truckers' Advice' started by Lepton1, Apr 7, 2013.

  1. Lepton1

    Lepton1 Road Train Member

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    Whether you are an O/O or a company driver, you should always be looking for the "sweet spot"... the combination of mph and gear ratio that will yield the best MPG. What is your current set up and "sweet spot"?

    My brother and I are driving a 2003 Kenworth with 13 speed transmission, and our sweet spot is about 69-71 mph in high gear. I've often read about other truckers having the sweet spot near 61-62 mph, and we've tried many different combinations of gears versus mph, but can't find a better spot than about 70 mph in highest gear...
     
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  3. dschmidt201

    dschmidt201 Light Load Member

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    So u found ur sweet spot above 70 miles an hour 71 lol
     
  4. Jseney12078

    Jseney12078 Light Load Member

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    The sweet spot is normally maximum torgue the engine puts out at a certain RPM. For Instance 515det is 1350rpms. At 1350, 13 speed, and 355 rears my speed is 62. However my engine is also rated maximum horsepower at 1550rpms, with that said, max torguis trumps max horsepower.
     
  5. Sheriff1/6

    Sheriff1/6 Medium Load Member

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    I'm driving a Volvo with a 10spd and it seems to get the best fuel economy at 57-59mph in 10th gear at around 1250rpm. I've also noticed that I get better mileage when I pay close attention to my shifting points. I still have a lot to learn about this whole business.
     
  6. The Bird

    The Bird Medium Load Member

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    I have a 2013 T700 with a 455 MX and a 13 speed. Rear end gears are 3.34. I keep my boost below 20lbs and my rpm's between 1250 and 1450. Hard to say what speed I cruise at since I'm rarely on the flat and get better MPG by not running cruise control. I average around 70,000 - 80,000 lbs gross running between Denver, Seattle, and LA. I'm usually getting mid to high 6's between Denver and Seattle and mid to low 7's running between Seattle and LA. I don't run overdrive in the 55 mph states and only use the overdrive once I get above 60 or so. I'm paid according to my MPG so I keep a pretty close eye on it.
     
  7. truckbuddha

    truckbuddha Medium Load Member

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    I've got a DD515, for me its 59 mph, but it varies wildly due to wt, hills, wind, you name it, its almost impossible to be consistent it seems. I am almost wondering if fuel consumption is also based on attitude. I do a lot of the west in high elevations, and I am convinced it has an effect on my fuel = thinner air = richer fuel being burned. I just don't know.
     
  8. FLATBED

    FLATBED Road Train Member

    and our sweet spot is about 69-71 mph in high gear.:biggrin_2559:Must be a real bummer when you cannot run that speed
     
    flightwatch Thanks this.
  9. cl8936

    cl8936 Light Load Member

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    My company pretty much preaches low rpms. I ran at 53 the past couple weeks, 1150 rpm, mpg last week was 8.6 and the week before that was 8.1. This week I had to run 65 @1450 rpm to make an appt. and burned over 100 gal. of fuel in a day and I'm at 6.8 mpg.
     
  10. BrianE

    BrianE Light Load Member

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    Speed limit in Texas is 75.
     
  11. skellr

    skellr Road Train Member

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    Today's word of the day is...

    limit
     
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