Announcement

Collapse

Get more Tips, Specs and Technical Data!

Did you know... this Forum is a service of the Studebaker Drivers Club? For more technical tips, specifications, history and tech data, visit the Tech Tips page at the SDC Homepage: www.studebakerdriversclub.com/tips.asp
See more
See less

Avanti R2 Power shift rear Axle Ratio

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Rear Axle: Avanti R2 Power shift rear Axle Ratio

    I have purchased a 3.31 set of gears and am looking to swap them in to replace the 3.73. I have 2.05/75x15 tires and the engine runs quite fast on the highway. Has anyone made this change and are you happy with it? all thinks being equal, it should slow down the rpms by 11 percent.

    Neil

  • #2
    Hi Neil, you will be running about 2600 RPM at 70 miles per hour. Great for highway driving and will stop you from doing burnouts off the line at a red light. It's a nice gear set and the chosen gear set for my Lark, which will be the touring car. My Hawk runs the 3.54:1 gearset what I would consider a good all round gear with higher RPM's on the highway at about 2800 RPM at 70 MPH.

    There is a 4X4 shop in Burlington the did my 4.56:1 drag racing gear set and set them up. I brought the axle to them and picked it up a few days later. http://www.national4wd.com They are on Harvester Road.


    Allen
    Last edited by studebaker-R2-4-me; 02-04-2014, 06:32 PM.
    1964 GT Hawk
    PSMCDR 2014
    Best time: 14.473 sec. 96.57 MPH quarter mile
    PSMCDR 2013
    Best time: 14.654 sec. 94.53 MPH quarter

    Victoria, Canada

    Comment


    • #3
      The 3.31 Ratio is the Standard Gear Ratio for an Automatic R1, and it is a very good "all around" compromise between decent acceleration and low RPM Interstate Cruising, it was the most common ratio for Larks and Hawks without Overdrive. You will like it with an R2.
      StudeRich
      Second Generation Stude Driver,
      Proud '54 Starliner Owner

      Comment


      • #4
        The '63 R1 Avanti I used to own had a 3.31 rear in it and it performed fine. It had a PowerShift (don't know what yours has), and if I felt the need for more from the start I'd just drop it in first to start off with.
        Poet...Mystic...Soldier of Fortune. As always...self-absorbed, adversarial, cocky and in general a malcontent.

        Comment


        • #5
          I have a 3:54 R-1 with 4 speed.
          Any advantage to going to 3:31 or 3:07?

          My days of stop light drags are far behind me:-)

          Comment


          • #6
            Sure there is a big advantage. Less Fuel consumption, less Noise, lower Engine RPM means less Oil will be burned and way less wear on the engine from less Revs per Mile.

            Only downside: a fair amount of low speed Power/Acceleration will be lost for those Red Light drag races!
            StudeRich
            Second Generation Stude Driver,
            Proud '54 Starliner Owner

            Comment


            • #7
              For that tire size and a 3.31 ratio, I calculate 2873 rpm at 70 mph. That doesn't account for transmission torque converter slippage.

              Norm

              Comment


              • #8
                Recommend You don't go higher (lower numerically) than 3.31. I installed 3.07 gears in My '63....R2, Auto, and they really killed the low end even when starting in manual first.

                Comment


                • #9
                  Originally posted by over50 View Post
                  For that tire size and a 3.31 ratio, I calculate 2873 rpm at 70 mph. That doesn't account for transmission torque converter slippage. Norm

                  I get 2950 at Randy's Ring and Pinion for P205X75R15 /Automatic / with 3.31, using his Tire Height of 27.1 both yours and mine sound WAY too high to me! With a 3.73 it's 3349 RPM also at 70 MPH.

                  It's a bit better with a better size for an Avanti; 215's @ 27.7 In. and 3.31 I get
                  2886 RPM.

                  The Cooper Trendsetter Radial P205X75R15 shows 26.98 Inches tall, so I guess that is not far off though.

                  Maybe we need to slow down!
                  Last edited by StudeRich; 02-04-2014, 05:54 PM.
                  StudeRich
                  Second Generation Stude Driver,
                  Proud '54 Starliner Owner

                  Comment


                  • #10
                    Originally posted by SN-60 View Post
                    Recommend You don't go higher (lower numerically) than 3.31. I installed 3.07 gears in My '63....R2, Auto, and they really killed the low end even when starting in manual first.
                    You always have the option of dropping a nice 5- or 6-speed Tremec in it...that will take care of low end problems with great cruising and economy!
                    Poet...Mystic...Soldier of Fortune. As always...self-absorbed, adversarial, cocky and in general a malcontent.

                    Comment


                    • #11
                      Originally posted by StudeRich View Post
                      Sure there is a big advantage. Less Fuel consumption, less Noise, lower Engine RPM means less Oil will be burned and way less wear on the engine from less Revs per Mile.

                      Only downside: a fair amount of low speed Power/Acceleration will be lost for those Red Light drag races!
                      My R2 Power Shift was ordered with a 4.09 axle.......3000 RPM @ 60 MPH . It was my daily driver for 3 years and was quickly changed to a 3.54 ratio, which I find is a good compromise.
                      Last edited by Packard8; 02-05-2014, 04:34 AM.
                      1996 Impala SS
                      1967 Jag XKE FHC
                      1963 Avanti R2
                      1963 Avanti R1
                      1956 Packard Patrician
                      1948 Jag Mk IV DHC
                      1909 Hupmobile Model 20

                      Comment


                      • #12
                        I have a 3.31 rear end in my Hawk (non-TT), and it is good for cruising on the highway. It'll also burn the right rear tire off at a stop light if I start in first gear. I am pretty happy with it.
                        sigpic
                        1961 Flamingo Studebaker Hawk

                        Comment


                        • #13
                          Originally posted by avantibngrant View Post
                          I have purchased a 3.31 set of gears and am looking to swap them in to replace the 3.73. I have 2.05/75x15 tires and the engine runs quite fast on the highway. Has anyone made this change and are you happy with it? all thinks being equal, it should slow down the rpms by 11 percent.

                          Neil
                          I drove a '64 R-2 Avanti with Powershift from California to Maryland running a 3.73 rear- not a pleasant experience especially out west where speed limits are high and not generally observed. I went clear down to a 3.07 and had no regrets. Still had plenty of power and it made the driving a lot more pleasant- could actually hear the AM-FM.
                          As a matter of fact, I converted my current R-1 Powershift Avanti to a 3.07 from a 3.54. Also no regrets.
                          Paul Johnson, Wild and Wonderful West Virginia.
                          '64 Daytona Wagonaire, '64 Avanti R-1, Museum R-4 engine, '72 Gravely Model 430 with Onan engine

                          Comment


                          • #14
                            Thanks for all the replies. I calculate 2873 for 70mph with the 3.31 or 3238 with the 3.73. I had a 73 GT one time with the 3.54.
                            What size of tires do you folks run on your Avanti's? Seems like a 235/70x15 would give 2751 at 70 with the 3.31. I have a ways to go to wear out the 2.05/75x15 tires first. Anyone run a larger size than the 205/17x15 on a 63/4 Avanti with good results?

                            Thanks
                            Neil

                            Comment


                            • #15
                              I run P215/70R15 tires on my car but it has 6" wide rims. That would not be good with the standard 5" rims. Replace the 15"x5" rims with something wider and you have more tire size options. Changing front tires and rim widths is more dicey than the rear...especially if you have sagging coil springs.
                              Poet...Mystic...Soldier of Fortune. As always...self-absorbed, adversarial, cocky and in general a malcontent.

                              Comment

                              Working...
                              X