Sprockets And Ratios And Stuff

Discussion in 'Vintage Classics' started by Obijohnkenobe, Oct 9, 2025.

  1. Obijohnkenobe

    Obijohnkenobe Well-Known Member

    Dec 14, 2020
    190
    83
    Tonbridge, Kent, UK
    I have a '72 Daytona 500 and she seems under geared to me. I'm in 4th from about 45mph upwards. I know the engines are 'buzzy at best of times but I keep thinking about changing the sprockets to make her rev less at higher speeds (sacrificing a bit of acceleration of course.) All I seem to read around the Web is changing the gearbox sprocket from the standard 19 (which the previous owner said it has, although I haven't checked myself), for a bigger one - probably just up to a 20. But why not go the easier route of lowering the teeth on the (bolt on) rear sprocket? The odd mention of 46 down to 43 has been made, but mainly its talk about changing the gearbox sprocket. I wondered what the prevailing wisdom was on changing front OR rear. What might be best to achieve a more relaxed ride at higher speeds? Obviously the principle is the same for any of you owners, but IF anyone has experience of the 500's it would be doubly useful.
     
    • Like Like x 1
  2. joe mc donald

    Subscriber

    Dec 26, 2014
    15,540
    1,000
    slough / burnham
    @Obijohnkenobe Yes i agree with the one tooth bigger for less revs and more relaxed engine. If i was still finding it Revy i would drop the rear sprocket by one or two teeth.
     
    • Like Like x 1
  3. TRIPLE X

    TRIPLE X Senior Member

    Sep 1, 2021
    668
    243
    Norfolk
    #3 TRIPLE X, Oct 11, 2025
    Last edited: Oct 11, 2025
    19 front / 46 rear gives a final drive ratio of 46 divided by 19 = 2.42.
    20 front / 46 rear = 2.30.
    19 front / 43 rear = 2.26.
    So changing the front to 20 or the rear to 43 has a similar affect with changing the rear sprocket slightly more beneficial in reducing revs. Changing sprocket sizes also affects the chain run so best to check that their will be no clearance issues between the chain, swingarm and chainguard and you might need to adjust the length of the chain.
     
    • Agree Agree x 2
    • Like Like x 1
  4. Obijohnkenobe

    Obijohnkenobe Well-Known Member

    Dec 14, 2020
    190
    83
    Tonbridge, Kent, UK
    Many thanks indeed. In actual fact finding a smaller rear sprocket is proving difficult, so I may be forced into changing the front anyway if I want to achieve a lower overall ratio!
     
    • Like Like x 1
    • Agree Agree x 1
  5. crispey

    crispey crispey creme de la creme

    Nov 6, 2014
    7,276
    1,000
    Uk
    Always useful
    https://www.gearingcommander.com/
     
    • Like Like x 2
  6. speedrattle

    speedrattle Senior Member

    Feb 19, 2021
    1,182
    243
    appalachia usa
    the 43 rear comes as a combined sprocket/brake drum, whereas the 46 is a separate ring that bolts onto a separate drum. you cannot go between the two sizes unless you switch out to a different wheel, and that would be awkward. you can go bigger in back with a custom sprocket, but not smaller because you run the chain into the bolts thathold the sprocket on.
     
    • Useful Useful x 1
    • Agree Agree x 1
  7. Obijohnkenobe

    Obijohnkenobe Well-Known Member

    Dec 14, 2020
    190
    83
    Tonbridge, Kent, UK
    Ah. That answers a lot of questions. Thank you
     
    • Like Like x 1
    • Agree Agree x 1
  8. speedrattle

    speedrattle Senior Member

    Feb 19, 2021
    1,182
    243
    appalachia usa
    the 43 drum/sprocket piece and the 46 separate drum and sprocket are interchangeable. like triple said, you may have to shorten the chain a bit.

    i play with sprockets enough that i just have separate chains cut to the correct length for each combo. when i change them out i ziptie the chain to the sprocket so i dont get confused.
     
    • Like Like x 1
    • Useful Useful x 1
Loading...

Share This Page