Logo

Formula for calculating speed with different sprocket sizes.

This is a discussion on Formula for calculating speed with different sprocket sizes. within the Z1K/Z750 Performance Upgrades forums, part of the Kawasaki Z1000, Ninja 1000, Z750 & Z-750S category; If you want to see how a sprocket change affects your speed vs. RPM the formula is as follows; Speed in MPH=RPMxFSTxTCMM, divided by PGRxGRxRSTx26817. ...

Results 1 to 13 of 13
  1. #1
    dippitydoo
    Guest dippitydoo's Avatar

    Formula for calculating speed with different sprocket sizes.

    If you want to see how a sprocket change affects your speed vs. RPM the formula is as follows;
    Speed in MPH=RPMxFSTxTCMM, divided by PGRxGRxRSTx26817.
    RPM=engine RPM
    FST=front sprocket teeth, (15,16 or whatever)
    TCMM=tire circumference in milimeters, (a 190 50 zr17 is about 1975mm)
    PGR=primary gear ratio, (Z1000 2003-2006 is 1.714)
    GR=gear ratio, (What gear your in ratio, Z1000 1st=2.571 2nd=1.941 3rd=1.555 4th=1.333 5th=1.200 6th=1.095, 2003-2006) choose one only.
    RST=rear sprocket teeth
    26817=26817 the number to convert from circunference in mm to MPH.
    So with a 16 tooth front and a 42 tooth rear in 6th gear at 11,000 RPM your speed would be 164 MPH. with a 15 tooth front retaining the 42 rear your top speed in 6th at 11,000 RPM would be 154 MPH.
    I hope this helps.

  2. # ADS

    Welcome to the largest Kawasaki Motorcycle Forum on the web.
    Registers users do not see these ads, register today - it's free!

  3. #2
    Rising Star Firehawk's Avatar
    Join Date
    Oct 2007
    Location
    San Diego, CA
    Posts
    160
    I made an Excel spreadsheet that will do it all for you, just put in the information.

    Let me know if you find anything wrong with it.

    http://www.mediafire.com/?nx3akovdhn0
    2003 Z1000 - black

  4. #3
    Site Elder canuckerstone's Avatar
    Join Date
    Apr 2007
    Posts
    758
    Cool!
    2005 Black Z1000 - nicely modded

  5. #4
    Supreme Being INTHERED's Avatar
    Join Date
    Sep 2007
    Location
    Marriottsville, MD
    Posts
    1,017
    I have an excel spreadsheet for the speed calulations that may be a bit different then Firehawks if you want I can email it to whoever wants it. I went to the link Firehawk provided but I could'nt download it due to the firewall here. I have attached a jpg that shows my spreadsheet output format. On my spreadsheet you enter in RPM and tire size (you can also change rear ratio but the default is stock 42/16) and the spreadsheet calculates the rest for each gear 1 thru 6 but it will not work on anything except a Z1000 since the transmission ratios are locked.

    INTHERED
    Attached Images Attached Images
    Last edited by INTHERED; 05-19-08 at 11:48 AM.
    2009 ORANGE/BLACK HD XR1200
    2008 ORANGE/BLACK KTM 990 SUPERDUKE, Akrapovic Slipons
    2008 ORANGE/BLACK HD FXDL, Vance & Hines Slipons, XIEDs, SE Heavy Breather AC
    SOLD! 2003 ORANGE Z1000, Yosh Slipons, PCIII, K&N w/stage 2 airbox

  6. #5
    Supreme Being greencheezeeta's Avatar
    Join Date
    Dec 2006
    Posts
    1,155
    Thanked
    1 times
    Or just go to: www.gearcommander.com


    I think thats the way it is spelled. Just pick your bike and make the proper adjustments.

  7. #6
    Supreme Being INTHERED's Avatar
    Join Date
    Sep 2007
    Location
    Marriottsville, MD
    Posts
    1,017
    www.gear what ????????? your link does not work
    2009 ORANGE/BLACK HD XR1200
    2008 ORANGE/BLACK KTM 990 SUPERDUKE, Akrapovic Slipons
    2008 ORANGE/BLACK HD FXDL, Vance & Hines Slipons, XIEDs, SE Heavy Breather AC
    SOLD! 2003 ORANGE Z1000, Yosh Slipons, PCIII, K&N w/stage 2 airbox

  8. #7
    Up-And Comer J.U.R.C.A's Avatar
    Join Date
    Sep 2006
    Posts
    52
    Quote Originally Posted by INTHERED View Post
    www.gear what ????????? your link does not work
    http://www.gearingcommander.com/

    Stay tuned

  9. #8
    Supreme Being INTHERED's Avatar
    Join Date
    Sep 2007
    Location
    Marriottsville, MD
    Posts
    1,017
    That link works.
    Now I wish I had'nt of wasted my time making my spreadsheet.
    I really like the section on determining chain length when changing sprockets.

    INTHERED
    2009 ORANGE/BLACK HD XR1200
    2008 ORANGE/BLACK KTM 990 SUPERDUKE, Akrapovic Slipons
    2008 ORANGE/BLACK HD FXDL, Vance & Hines Slipons, XIEDs, SE Heavy Breather AC
    SOLD! 2003 ORANGE Z1000, Yosh Slipons, PCIII, K&N w/stage 2 airbox

  10. #9
    Site Elder z1000pwnr's Avatar
    Join Date
    Dec 2007
    Posts
    500
    That website rocks ty!

  11. #10
    Up-And Comer water's Avatar
    Join Date
    Feb 2010
    Location
    Fairfax, CA
    Age
    29
    Posts
    119

    Thumbs up

    Awesomeness!

    Helped me decide on -1/+2 conversion... I was a bit concerned that my cruising rpm would be higher - but it's not that significant... And I get to use the same chain :-D

  12. #11
    Silver Member buster's Avatar
    Join Date
    May 2004
    Location
    pinellas park Fl.
    Age
    58
    Posts
    1,678
    Thanked
    1 times
    Why make it so complicated ? All you need is a base point. Let us say 16/42 is 4krpm at 60mph. 42 divided by 16 is 2.625 and 42 divided by 15 is 2.8 2.635 divided by 2.8 is .9375 and .9375 times 60 is 56.25 so lowering one tooth in this case changes 4k at 60mph to 56 mph. Anyone but me understand this ?
    It is better to remain silent and be thought of as a fool,then to open your mouth and remove all doubt. Abraham Lincoln.

  13. #12
    Site Elder ballsdeepracing's Avatar
    Join Date
    Apr 2008
    Location
    Beautiful Coeur d'Alene, ID
    Posts
    690
    am I supposed to do this while I'm riding? it sounds like riding to canada and converting MPH to KPH. My head hurts already
    2005 z1000 Candy Blood Red
    Enough mods to build another bike
    "I want to make this thing fly!"

  14. #13
    dippitydoo
    Guest dippitydoo's Avatar

    Yes

    Quote Originally Posted by buster View Post
    Why make it so complicated ? All you need is a base point. Let us say 16/42 is 4krpm at 60mph. 42 divided by 16 is 2.625 and 42 divided by 15 is 2.8 2.635 divided by 2.8 is .9375 and .9375 times 60 is 56.25 so lowering one tooth in this case changes 4k at 60mph to 56 mph. Anyone but me understand this ?
    Yes but people are to lazy to do any calculations. A real human will use a formula and do it on paper not with a calculator. I think that is one of the reasons we are all f****d.

Ads

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

Search tags for this page

formula for sprocket speed
,
how to calculate sprocket sizes
,
motorcycle sprocket size vs speed
,

sprocket calculation formula

,

sprocket ratio formula

,
sprocket ratio formulas
,
sprocket size and speed
,
sprocket speed calculator
,
sprockets calculation formula
,
sproket and speed calculation
Click on a term to search for related topics.