Rear gear change


Donating Member
I would like to increase the size of the rear gear on my Busa. The local shop said to wait until the chain was spent and replace both gears and the chain at the same time. I have 5800 miles on the bike now. If I did just do the rear gear, would I need a new (longer chain)? How many teeth could I add with out getting a longer chain. Any other issues?



Hayabusa Immortal
If you do 42/43 on the rear, your wheelbase will be effectively shortened but you should not need a new chain. Some people have even gone up on the rear and removed a link from the chain.

Stock is 40 teeth and you can get anywhere from 37-53, although 43, maybe 44, is probably as high as you want to go. Otherwise you should be looking at an extended swingarm, longer chain, front sprocket, etc.

What is your goal, straight line acceleration or better cornering performance? If it is the latter, go with a 42. If it is the prior, I would change the front sprocket to a lower tooth setting.


Donating Member
Thanks for the advice. I guess I am looking for more usable power. I am not a top-speed guy and I more interested in fast lauches and roll-on power. Cornering is less important to me. You mentioned lowering the front sprocket, but a few local wrenches discouraged this due to the chain "binding" or not being able to flow around the smaller diameter. What are your thoughts on this? Also, do you recommend a particular brand or vendor for the gear? Finally, would it be ok to do this now with nearly 6k on the hardware or should I wait and change both sprockets and the chain all at once?

Thanks a Ton!

Latest Bikes

  • Hayabusa Addict
    From back to front; 2014 9.99 index champion 2005 all motor class...
    • Motonutz916
    • Updated:
  • My Gen 3 Busa
    Photos of my 10 year freshen up on my 2009 Hayabusa. Parts highlights...
    • fallenarch
    • Updated:
  • Art 05 Hayabusa
    hayabusa 05
    • VIPER
    • Updated:
  • toads L2
    L2 as it is ridden today
    • ROADTOAD1340
    • Updated:
  • Busa in another part of Cornwall
    Cotehele pretty spot but residents didn't appreciate the Busa. I guess...
    • Grumpyoldjohn
    • Updated:

Forum statistics

Latest member
Tim B