Jump to content

  •  

  • Welcome to BigMackTrucks.com

    Welcome to BigMackTrucks.com, the best resource on the Internet for Antique, Classic and Modern Mack Trucks!  

     

    Please login or register to take advantage of everything BMT has to offer.  Memberships are Free and offer many benefits:

     

    • Start new topics and reply to others
    • Subscribe to topics and forums to get automatic updates
    • Showcase your trucks in our Garage
    • Photo Gallery, Member Blogs and much more...
    • Add events to our community calendar
    • Create your own profile and make new friends
    • Customize your experience!
    • Mack Dealer and Corporate personnel can contact the ADMIN after registration for access to the Dealer Forums.

    If you are having trouble logging in or haven't received your validation email, you can post as a guest in the Guest Forum.


    login  register
    Guest Message by DevFuse
     

    Photo

    Gear Ratio



    • Please log in to reply
    52 replies to this topic

    #1 OFFLINE   bigen

    bigen

      BMT Certified Know-It-All!

    • Pedigreed Bulldog
    • PipPipPipPipPipPipPipPipPipPip
    • 1,174 posts
    • Location:30 miles south st.louis mo
    • Make:mack
    • Model:chn 613 rawhide 007504
    • Year:2007

    Posted 18 March 2010 - 04:01 AM

    i had a 13 spd overdrive with 373 ratio, in the 55mph states it turned 1200 rpm's it lugged to much
    i now have a 13spd no overdrive and 393 ratio it seems to do a great job at any speed.and it gets better mpg at 70 mph than 60 mph. and pulls like it's pissed off.
    it would seem if i had overdrive i would need 411 ratio.
    i see trucks with overdrive and 342 ratio how can this work????????
    i know the guy's specing these trucks are smarter than me, but what am i missing????????

    #2 OFFLINE   daveigou

    daveigou

      BMT Forum Guru

    • Pedigreed Bulldog
    • PipPipPipPipPipPipPipPipPip
    • 563 posts

    Posted 18 March 2010 - 06:39 AM

    What model transmission do you have? I didn't know there was any recent 15-1600 series 13 speeds that did not have overdrive.

    Dave

    See my Flickr photostream page

     

    http://www.flickr.co...s/96692978@N05/

     

    Linkedin

     

    http://www.linkedin....igou/38/321/8b0


    #3 OFFLINE   bigen

    bigen

      BMT Certified Know-It-All!

    • Pedigreed Bulldog
    • PipPipPipPipPipPipPipPipPipPip
    • 1,174 posts
    • Location:30 miles south st.louis mo
    • Make:mack
    • Model:chn 613 rawhide 007504
    • Year:2007

    Posted 18 March 2010 - 07:25 AM

    What model transmission do you have? I didn't know there was any recent 15-1600 series 13 speeds that did not have overdrive.

    Dave

    i dont have the build sheet on my truck, i understand it has a slight overdrive, but not like some of the stuff thats out there.
    i guess i should have made my question more clear. i cant figure how to drive a truck that you have to wind up that tight to get it in overdrive, and at the slightest grade its lugging its guts out??????

    #4 OFFLINE   David

    David

      BMT Certified Know-It-All!

    • BMT Benefactor
    • 3,176 posts
    • Location:Raleigh,NC

    Posted 18 March 2010 - 07:34 AM

    Get the numbers off the side of the transmission, rear ratio and tire size. Then we can help you.

    #5 OFFLINE   bigen

    bigen

      BMT Certified Know-It-All!

    • Pedigreed Bulldog
    • PipPipPipPipPipPipPipPipPipPip
    • 1,174 posts
    • Location:30 miles south st.louis mo
    • Make:mack
    • Model:chn 613 rawhide 007504
    • Year:2007

    Posted 18 March 2010 - 07:38 AM

    a friend of mine got an 06 pete. i had never driven one so i took it down the road and back about 20 miles.
    dont know anything about them but was told it had a 475 cummings and 10spd overdrive i had to wind it like hell to get it in o/d then at first hill it fell on it's face, so rather than saying hey buddy i think your new truck is a piece of crap, i thought i would get on here and see what im doing wrong.

    #6 OFFLINE   bigen

    bigen

      BMT Certified Know-It-All!

    • Pedigreed Bulldog
    • PipPipPipPipPipPipPipPipPipPip
    • 1,174 posts
    • Location:30 miles south st.louis mo
    • Make:mack
    • Model:chn 613 rawhide 007504
    • Year:2007

    Posted 18 March 2010 - 07:43 AM

    Get the numbers off the side of the transmission, rear ratio and tire size. Then we can help you.

    mine is fine wouldn't change a thing

    #7 OFFLINE   Gambi80

    Gambi80

      BMT Certified Know-It-All!

    • Pedigreed Bulldog
    • PipPipPipPipPipPipPipPipPipPip
    • 1,042 posts
    • Location:Ladd, IL
    • Make:Mack
    • Model:CH 613
    • Year:1997

    Posted 18 March 2010 - 10:34 AM

    That's the beauty of a 10sp. I think the newer ISX's and especially the Cat Accert motors have a very narrow powerband and the high(numericaly low) gear ratio is needed to keep the motor at 1300-1400rpm at cruising speed to get decent mpg.
    Ever wonder how a blind person knows when to stop wiping?

    Posted Image

    #8 OFFLINE   bts-4120

    bts-4120

      BMT Veteran VIP

    • Big Dog
    • PipPipPipPipPipPipPipPip
    • 188 posts
    • Make:Mack
    • Model:CX613
    • Year:2001

    Posted 18 March 2010 - 07:27 PM

    if its a B series Fuller it would have a .86 OD in high hear roughly the same as a half gear down in a A series, pretty rare, I was under the assumption your Rawhide had the Mack 13

    #9 OFFLINE   bigen

    bigen

      BMT Certified Know-It-All!

    • Pedigreed Bulldog
    • PipPipPipPipPipPipPipPipPipPip
    • 1,174 posts
    • Location:30 miles south st.louis mo
    • Make:mack
    • Model:chn 613 rawhide 007504
    • Year:2007

    Posted 18 March 2010 - 10:00 PM

    if its a B series Fuller it would have a .86 OD in high hear roughly the same as a half gear down in a A series, pretty rare, I was under the assumption your Rawhide had the Mack 13

    yes my rawhide has a mack 13

    #10 OFFLINE   bigen

    bigen

      BMT Certified Know-It-All!

    • Pedigreed Bulldog
    • PipPipPipPipPipPipPipPipPipPip
    • 1,174 posts
    • Location:30 miles south st.louis mo
    • Make:mack
    • Model:chn 613 rawhide 007504
    • Year:2007

    Posted 18 March 2010 - 10:04 PM

    That's the beauty of a 10sp. I think the newer ISX's and especially the Cat Accert motors have a very narrow powerband and the high(numericaly low) gear ratio is needed to keep the motor at 1300-1400rpm at cruising speed to get decent mpg.

    so you are saying the new macks with 342 gears and a 10spd o/d are that big of a pos.
    the shut down on the pete is 69mph so i couldn't get a run at anything
    it feels like it needs to be in 9th gear exept when decending a hill. uless you want to feel like you have an engine brake then you have to run in 9th also??????????????
    i cant see building a truck that wacked out so i must be driving it wrong??????
    65mph is around 12oo rpm's

    #11 OFFLINE   phantom309

    phantom309

      BMT Veteran VIP

    • Big Dog
    • PipPipPipPipPipPipPipPip
    • 138 posts
    • Location:Barrie Ont. Canada
    • Make:Mack
    • Model:B-85
    • Year:1957

    Posted 19 March 2010 - 07:27 PM

    i now have a 13spd no overdrive and 393 ratio it seems to do a great job at any speed.and it gets better mpg at 70 mph than 60 mph. and pulls like it's pissed off.


    If you're running 11R 22.5 tires, with a direct drive 13 speed and 3.93 gears engine's turning 2,200 rpm @ 70 mph.
    My guess is you have an overdrive. :idunno:

    #12 OFFLINE   Rob

    Rob

      Bloated Dieselholic

    • Pedigreed Bulldog
    • PipPipPipPipPipPipPipPipPipPip
    • 10,191 posts
    • Location:Mack Paradise-Farmington, Illinois
    • Make:Mack
    • Model:A-40H, B-61T, B-61ST, B-67ST, B-61S, RL-797LST, RL-797LST, RL-755L, R795, R612ST
    • Year:1951 1957 1958 1962 1964 1973 1974 1978 1977 1980

    Posted 19 March 2010 - 07:42 PM

    My guess is that if it has more than one tooth on top, and two on the bottom, (like me) I'll never understand either.

    Rob

    Going through life knowing considerably more about nothing than the next person.

    ParadeRain.gif
    Raining on your parade


    #13 OFFLINE   bts-4120

    bts-4120

      BMT Veteran VIP

    • Big Dog
    • PipPipPipPipPipPipPipPip
    • 188 posts
    • Make:Mack
    • Model:CX613
    • Year:2001

    Posted 19 March 2010 - 10:53 PM

    yes my rawhide has a mack 13




    that would be a double over box .71 hi gear, I would think fuller 13 and 3.70's and 3.94 with a Mack 13 would be geared pretty close to the same as far as rpms in high gears, but I could be wrong

    #14 OFFLINE   Gambi80

    Gambi80

      BMT Certified Know-It-All!

    • Pedigreed Bulldog
    • PipPipPipPipPipPipPipPipPipPip
    • 1,042 posts
    • Location:Ladd, IL
    • Make:Mack
    • Model:CH 613
    • Year:1997

    Posted 20 March 2010 - 12:42 AM

    so you are saying the new macks with 342 gears and a 10spd o/d are that big of a pos.
    the shut down on the pete is 69mph so i couldn't get a run at anything
    it feels like it needs to be in 9th gear exept when decending a hill. uless you want to feel like you have an engine brake then you have to run in 9th also??????????????
    i cant see building a truck that wacked out so i must be driving it wrong??????
    65mph is around 12oo rpm's


    I was being sarcastic about the 10sp. They don't have many options when it comes to cruising speed, you either wind the $hit out of it or lug it. I drove 10 speeds for a few years, now I have an 18sp and love it...there's a gear wherever I need it.
    Ever wonder how a blind person knows when to stop wiping?

    Posted Image

    #15 OFFLINE   bigen

    bigen

      BMT Certified Know-It-All!

    • Pedigreed Bulldog
    • PipPipPipPipPipPipPipPipPipPip
    • 1,174 posts
    • Location:30 miles south st.louis mo
    • Make:mack
    • Model:chn 613 rawhide 007504
    • Year:2007

    Posted 20 March 2010 - 03:49 AM

    that would be a double over box .71 hi gear, I would think fuller 13 and 3.70's and 3.94 with a Mack 13 would be geared pretty close to the same as far as rpms in high gears, but I could be wrong

    with a fuller 13 and 373 55mph about 1200 rpm's
    the mack 13 and 393 55mph about 1300 rpm's

    #16 OFFLINE   RowdyRebel

    RowdyRebel

      BMT Certified Know-It-All!

    • Pedigreed Bulldog
    • PipPipPipPipPipPipPipPipPipPip
    • 2,519 posts
    • Location:SoIL
    • Make:Mack
    • Model:CH613
    • Year:2001

    Posted 20 March 2010 - 05:37 PM

    with a fuller 13 and 373 55mph about 1200 rpm's
    the mack 13 and 393 55mph about 1300 rpm's



    I wanna say the Fuller prolly has a .73 OD. The Mack is a .71. The only detail you are omitting is the tire size, which makes a difference. 11R24.5's are roughly 44". LP 24.5's and 11R22.5's are both around 42". LP 22.5's are going to be in the 40" ballpark.

    http://www.4lo.com/calc/gearratio.htm

    I would guess the Fuller 13/3.73 is riding on either LP 24.5's or 11R22.5's...either way would put the truck at 55 mph @ 1200 rpm.

    I would also guess the Mack 13/3.93 is riding on LP 22.5's, which would put the truck at 55 mph @ 1300 rpm.
    When approaching a 4-way stop, the vehicle with the biggest tires has the right of way!

    #17 OFFLINE   RowdyRebel

    RowdyRebel

      BMT Certified Know-It-All!

    • Pedigreed Bulldog
    • PipPipPipPipPipPipPipPipPipPip
    • 2,519 posts
    • Location:SoIL
    • Make:Mack
    • Model:CH613
    • Year:2001

    Posted 20 March 2010 - 05:46 PM

    I was being sarcastic about the 10sp. They don't have many options when it comes to cruising speed, you either wind the $hit out of it or lug it. I drove 10 speeds for a few years, now I have an 18sp and love it...there's a gear wherever I need it.



    Yup. My thoughts exactly. I just wish I had more gears in reverse....wouldn't mind a lower "low" either. I wonder why they don't move 4th gear to the high range "low" position, move all of the low range gears up one hole, and add a lower "low" gear? ...or better yet, why can't they just put a splitter on the T310ME to get the 20 forward gears w/ multiple shift possibilities in reverse, too B)
    When approaching a 4-way stop, the vehicle with the biggest tires has the right of way!

    #18 OFFLINE   Gambi80

    Gambi80

      BMT Certified Know-It-All!

    • Pedigreed Bulldog
    • PipPipPipPipPipPipPipPipPipPip
    • 1,042 posts
    • Location:Ladd, IL
    • Make:Mack
    • Model:CH 613
    • Year:1997

    Posted 20 March 2010 - 07:14 PM

    Yup. My thoughts exactly. I just wish I had more gears in reverse....wouldn't mind a lower "low" either. I wonder why they don't move 4th gear to the high range "low" position, move all of the low range gears up one hole, and add a lower "low" gear? ...or better yet, why can't they just put a splitter on the T310ME to get the 20 forward gears w/ multiple shift possibilities in reverse, too B)


    Why not just slide some 2 speed rear ends underneath your truck? 36 speeds!

    I wish my 18sp had a normal speed reverse...it just creeps.
    Ever wonder how a blind person knows when to stop wiping?

    Posted Image

    #19 OFFLINE   RowdyRebel

    RowdyRebel

      BMT Certified Know-It-All!

    • Pedigreed Bulldog
    • PipPipPipPipPipPipPipPipPipPip
    • 2,519 posts
    • Location:SoIL
    • Make:Mack
    • Model:CH613
    • Year:2001

    Posted 20 March 2010 - 07:39 PM

    Why not just slide some 2 speed rear ends underneath your truck? 36 speeds!

    I wish my 18sp had a normal speed reverse...it just creeps.



    ....'cuz Mack don't have any :rolleyes:


    Seriously, if I were spec'ing any OTHER brand truck, I'd do it....but why buy a Mack if'n ya ain't got a Mack drivetrain? :unsure:


    Hell, a DT521/RT521 tandem with a 3.70/5.04 gearset riding on a 52K Hendrickson AR2 air walking beam suspension would be a pretty sweet setup...'specially with 600+ HP under the hood and an 18 speed transmission and some aggressive tires like Michelin's XDE M/S* in 11R24.5 B)
    When approaching a 4-way stop, the vehicle with the biggest tires has the right of way!

    #20 OFFLINE   RowdyRebel

    RowdyRebel

      BMT Certified Know-It-All!

    • Pedigreed Bulldog
    • PipPipPipPipPipPipPipPipPipPip
    • 2,519 posts
    • Location:SoIL
    • Make:Mack
    • Model:CH613
    • Year:2001

    Posted 20 March 2010 - 07:54 PM

    ....'cuz Mack don't have any :rolleyes:


    Seriously, if I were spec'ing any OTHER brand truck, I'd do it....but why buy a Mack if'n ya ain't got a Mack drivetrain? :unsure:


    Hell, a DT521/RT521 tandem with a 3.70/5.04 gearset riding on a 52K Hendrickson AR2 air walking beam suspension would be a pretty sweet setup...'specially with 600+ HP under the hood and an 18 speed transmission and some aggressive tires like Michelin's XDE M/S* in 11R24.5 B)




    ...yeah, I'm good at thinking about spending money I ain't got :wacko:
    When approaching a 4-way stop, the vehicle with the biggest tires has the right of way!




    0 user(s) are reading this topic

    0 members, 0 guests, 0 anonymous users