Rear End Gear Ratio

Discussion in 'Ask An Owner Operator' started by Gazoo, Aug 5, 2007.

?

What Rear Ratio

Poll closed Aug 12, 2007.
  1. 2.79

    0 vote(s)
    0.0%
  2. 2.93

    50.0%
  3. 3.58

    25.0%
  4. *

    3.73

    25.0%
  1. rank

    rank Road Train Member

    Joined:
    Feb 11, 2010
    Messages:
    9,919
    Thanks Received:
    113,508
    Location:
    50 miles north of Rochester, NY
    0
    yeah obviously I haven't driven my 13 in several months. Been driving an old 15 single over.
     
  2. kelgar50

    kelgar50 Medium Load Member

    Joined:
    Feb 1, 2007
    Messages:
    334
    Thanks Received:
    218
    Location:
    Bakersfield,CA
    0
    My brain must have been sleeping.
    It was a single over 13 .86 o/d.
    And yes I called him to see what happened to him. He could not keep up and I ran off and left him.
     
  3. rank

    rank Road Train Member

    Joined:
    Feb 11, 2010
    Messages:
    9,919
    Thanks Received:
    113,508
    Location:
    50 miles north of Rochester, NY
    0
    I'm not familiar with a single over 13 with a .86 high gear either but regardless, you saying that you walked away from a 3.55 rear with your 2.93 rear doesn't make sense to me. First two scenarios that I can think of are either his ECM is cutting fuel or he backed out of it for some reason....high EGT or coolant temps.
     
    cnsper Thanks this.
  4. kelgar50

    kelgar50 Medium Load Member

    Joined:
    Feb 1, 2007
    Messages:
    334
    Thanks Received:
    218
    Location:
    Bakersfield,CA
    0
    It's all in the gear steps in the trans.
    They make different gear sets for the trans.
    When I first was told the gear ratio of the truck I was about scared off from it.
    Then I was told about how they have different gear sets within the trans and that makes up for it.
     
  5. rank

    rank Road Train Member

    Joined:
    Feb 11, 2010
    Messages:
    9,919
    Thanks Received:
    113,508
    Location:
    50 miles north of Rochester, NY
    0
    The steps are just dealing with the rpm drop between gears. I don't get why he couldn't find a gear to match your final ratio and pull the hill right along with you. What model 13 do you have compared to your friend?
     
    Dwardell662 Thanks this.
  6. kelgar50

    kelgar50 Medium Load Member

    Joined:
    Feb 1, 2007
    Messages:
    334
    Thanks Received:
    218
    Location:
    Bakersfield,CA
    0
  7. Dwardell662

    Dwardell662 Light Load Member

    Joined:
    Feb 8, 2017
    Messages:
    83
    Thanks Received:
    10
    0
    Im looking at a 1998 freightliner century with 12.7 Detroit 60series. It have a 10 sp tranny with 2.79 gear ratio. Is it gd to go otr with? Performance? Mpg?
     
  8. Cowpie1

    Cowpie1 Road Train Member

    Joined:
    Nov 25, 2008
    Messages:
    5,569
    Thanks Received:
    4,651
    Location:
    Kellogg, IA
    0
    2.79, that is probably direct drive top gear and would be turning 1600 RPM at 65 mph. Not terrible, but I seem to get best balance of performance and mpg turning 1475-1500 at 65. At 65 or less it would work.
     
    Dwardell662 Thanks this.
  9. Dwardell662

    Dwardell662 Light Load Member

    Joined:
    Feb 8, 2017
    Messages:
    83
    Thanks Received:
    10
    0
    Thanks for replying. I'm looking at this truck and thinking would it be a good truck to take otr. I didn't kno Detroit engines had Rockwell tranny
     
  10. Dwardell662

    Dwardell662 Light Load Member

    Joined:
    Feb 8, 2017
    Messages:
    83
    Thanks Received:
    10
    0
    Do u have a freightliner? What make/model?