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Changing gearing on a shaft drive.

Discussion in 'Technical and Troubleshooting Torque' at netrider.net.au started by VladTepes, Sep 5, 2011.

  1. I know its piss easy to change gearing on a chain drive bike by fiddling with rear sprockets, but what about a shaft drive bike?

    Let's say, for example, one wanted a Guzzi with more "poke"

    How is it done?


     
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  2. You could find one that's running?
     
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  3. Bit unlikely........:D.

    Seriously though, the only real option is if the manufacturer offered a model with a physically interchangeable final drive with a different ratio in it. That way you might be able to find a used unit to fit or get a new crown wheel and pinion to rebuild your existing unit.

    BMW were quite good about this, offering the K-Series with several different FD ratios (although the spread is not huge) which, with careful attention to driveshaft compatibility, will fit (almost) any contemporary K. I've no idea if Moto Guzzi have been as accomodating recently.

    Failing that, you're stuck with getting custom gears made up, which would be likely to be prohibitively expensive unless an owners club has had a batch made or an aftermarket manufacturer offers something that will fit.
     
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  4. Sounds like your limited to 1. losing weight off the bike (or belly), or 2. more power from the engine.
     
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  5. You could also change the rear wheel size, but this would only have a slight effect on the gearing & probably a detrimental effect on handling.
     
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  6. Fairly easy and common mod for Boulevards/Volusias.

    C50 (VL800)s can fit a C90 final drive which gives different ratios.
     
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  7. Oddly enough, RS series K bikes have taller FD's than the LT's or plain Janes. And no one wants the lower ratios either. So better acceleration is not too hard to achieve. (If you have an RS)
     
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  8. My pet theory is that it was something to do with BMW wanting the RS to post the highest top speed of the range in road tests and wanting the heavier RT to be not too much of a slug off the line.

    When my RS did its FD splines (They all do that Sir :D), I put on an RT unit. Frankly, the difference on the road in the real world was negligible, although, if my K100 track weapon ever happens I'll be sticking with the RT unit or looking for (IIRC) a 750 one for even lower gearing.
     
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