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GSR25 w/GP460 swapped.EXPERTS GEARING QUESTIONS

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  • GSR25 w/GP460 swapped.EXPERTS GEARING QUESTIONS

    as the title says.i have a GSR25 with soon to be swapped over to the GP460 engine w/78mm engine mount.ok now for the questions..i recently bought a black magic metal 64 tooth rear sprocket and also installed it since the old one had 84 tooth which to me was to big.i'm more into top speed.anyhow i also bought an 8 tooth and a 9 tooth for the front qs soon as i get the engine i will be installing.
    now for the main question.
    what kinda top speed should i expect on my GSR25 stock wheels,stock engine with only a high flow air filter,stock muffler,8/64 gearing and if i go with the 9/64 gearing..my weight is 130lbs.
    this is a question that i have been having for a very long time now.i tried seeing youtube videos with no
    success so hopefully you guys that have the same gearing and engine as my ped could please give me a rough estimate on what my top speed will be.thanks you guys.
    boxeroni

  • #2
    http://www.adaracing.com/calculators/gearing-gsr.php

    The ada calculator will help you

    Comment


    • #3
      Originally posted by DaBoy View Post
      thanks.i was looking for more of a real life estimate.from guys that have that same setup of gp460 bone stock and a 9/64 gearing or an 8/64 gearing.but thanks anyways.
      boxeroni

      Comment


      • #4
        It'll pull 7/64 if you are light, 8/64 if you are light and you port/pipe it.

        8/76 is the gearing of choice for most guys. Here is a ratio chart...

        Lookin for a new goat...mine is wore the hell out!

        Originally posted by Dirtmonkey
        Slitz is taken. We'll let you be Clitz.

        Comment


        • #5
          Ada calculater
          10" wheel diameter
          13000 rpms
          It's better to be PISSED OFF
          than PISSED ON
          Don't forget to grease your muffler bearings

          Comment


          • #6
            [QUOTE=cablescum;89924]It'll pull 7/64 if you are light, 8/64 if you are light and you port/pipe it.

            8/76 is the gearing of choice for most guys.

            thank's cable.I actually already bought and installed a 64 tooth sprocket for the rear and also have a 9 tooth pinion for the front.oh and i'm a very light rider.i weight between 127-130lbs (lots of cardio/boxing)so with my weight,a GP460 bone stock with my gearing of 9/64 how fast do you think it will do on top end speed?also will i have a really sloooow take off speed with that setup?
            i will be porting my engine,adding skirts to the piston as soon as i buy a pipe.but in the meantime i will be running stock.
            if only someone had a video with a gp460 with my same exact setup to get an idea of the take off speed and top end speed woul be.i seen afew videos of a gtr stock but with an 8/68 gearing an it sor
            boxeroni

            Comment


            • #7
              Originally posted by Norcaliboxer View Post
              Ada calculater
              10" wheel diameter
              13000 rpms
              ok thanks.well i like the numbers it says my ped should do..hopefully it is accurate.
              boxeroni

              Comment


              • #8
                The gearing is too tall, it the engine won't pull it.

                It's like going up a mountain in a car in 5th gear.
                Lookin for a new goat...mine is wore the hell out!

                Originally posted by Dirtmonkey
                Slitz is taken. We'll let you be Clitz.

                Comment


                • #9
                  Originally posted by BOXER951 View Post
                  ok thanks.well i like the numbers it says my ped should do..hopefully it is accurate.
                  9/64 say goodbye to your clutch go 8/68 you will hit 50 mph all day . good all around power etc. You will never pull 13k geared at 9/64
                  PEDFEST 2013 ALUMNUS
                  PEDFEST 2014 ALUMNUS
                  PEDFEST 2015 ALUMNUS

                  Comment


                  • #10
                    The never ending conundrum of gearing!

                    Like mentioned, 9/64 is just to damn tall for a stock 460. And I think Cable said it best about going up hill in 5th gear. On the calculator the numbers look great, problem is with that gearing your engine just will not rev that high. The 460 is a high RPM engine, but does lack on torque compared to dual ring piston engines. Especially the G62, which I'm sure you have noticed the tall gearing the 60 is able to pull, different animal.

                    If you insist on running a 9 tooth pinion, I recommend a 76 tooth rear sprocket. The 76 is a very well rounded rear sprocket, it will allow you to keep some bottom end while achieving a good top end. Also it has to do with surface area of the sprocket. I will attempt to find some literature to explain this "theory".
                    Hell Fab

                    Comment


                    • #11
                      Here's a link that gets into the explanation of gearing and all aspects. However it is a long read and I understand most do not like to read that much, not sure why?!

                      http://content.vexrobotics.com/docs/...ex_unit_06.pdf

                      However I will do my best to explain using bicycle gearing as an example. Different animal of course, but same concept as gearing is gearing no matter which way you slice it.

                      Have you noticed the kids that run these little sprockets on their BMX bikes these days? It mainly has to do with them being weight weenies to help perform tricks. On the same note, look at the guys that are racing BMX bikes. They run much larger gears but still use close to the same ratio.

                      BMX Street/Trick bikes popularly run 23 tooth front and 8 tooth rear sprockets.
                      For a ratio of 1/2.88 revolutions. I know it's backwards from GoPeds, but bear with me.

                      BMX Race bikes popularly run 52 tooth front and 18 tooth rear sprockets.
                      For a ratio of 1/2.89 revolutions. Very similar ratio, but a huge difference in the overall outcome.

                      While a guy on a BMX with the "smaller" gears (same ratio) may be able to start the race and maintain for the first leg. He will suffer drastically to finish the race because the amount of energy put forth on the "smaller" gears. This is where the "large" gears will prevail. Again the large gears have the same ratio, but the load and energy put forth is drastically decreased as it is spread to a larger surface area due to the larger size gears.

                      In conclusion, from my experiences running 8/68 for a ratio of 8.50/1 on my 40 with the G43. I actually achieved better overall acceleration and top speed from running 9/76 for a ratio of 8.44/1. This is attributed by the amount of surface area for the engines force to be spread upon.


                      Side note: This is the reason that 6 tooth pinions do not hold up and inevitably wear quickly and/or shear off leaving the threaded portion of the pinion in the bell. Although great for beginners, a 6 tooth pinion can not take the continued abuse (excessive force) that is applied from the engine.

                      Just some food for thought. That's it, that's all I know....
                      Hell Fab

                      Comment


                      • #12
                        [QUOTE=Depths of Hell;89955]Here's a link that gets into the explanation of gearing and all aspects. However it is a long read and I understand most do not like to read that much, not sure why?!

                        http://content.vexrobotics.com/docs/...ex_unit_06.pdf

                        However I will do my best to explain using bicycle gearing as an example. Different animal of course, but same concept as gearing is gearing no matter which way you slice it.

                        Have you noticed the kids that run these little sprockets on their BMX bikes these days? It mainly has to do with them being weight weenies to

                        In conclusion, from my experiences running 8/68 for a ratio of 8.50/1 on my 40 with the G43. I actually achieved better overall acceleration and top speed from running 9/76 for a ratio of 8.44/1. This is attributed by the amount of surface area for the engines force to be spread upon.

                        i also had a 76tooth rear with a 7 tooth pinion on my GSR40 was doing about 32-35mph.i then switched the 76t to a 64 tooth and i was able to run 38mph then i bought a 9 tooth pinion and did 40.7mph.that's what made me buy another rear 64t for my GSR25 with soon to be 460 swapped.and maybe an 8 tooth pinion with the 64 tooth rear would be ok?64 t diameter is similar to the 68 t

                        BTW i do appreciate all you guys input.
                        boxeroni

                        Comment


                        • #13
                          Originally posted by greenborroco View Post
                          9/64 say goodbye to your clutch go 8/68 you will hit 50 mph all day . good all around power etc. You will never pull 13k geared at 9/64
                          hey green.i seen your youtube video of your GTR46R doing 54mph
                          what gearing were you running?
                          boxeroni

                          Comment


                          • #14
                            Green is magic, he wills it to go that fast...and it does.
                            Lookin for a new goat...mine is wore the hell out!

                            Originally posted by Dirtmonkey
                            Slitz is taken. We'll let you be Clitz.

                            Comment


                            • #15
                              Originally posted by greenborroco View Post
                              9/64 say goodbye to your clutch go 8/68 you will hit 50 mph all day . good all around power etc. You will never pull 13k geared at 9/64
                              well 8/68 doing 50mph sounds good to me but since i already installed the 64 tooth and i also have an 8 tooth layin around somewhere,i think that would still work right? 8/64 8/68 not much of a difference.
                              boxeroni

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