All is not lost

Discussion in 'Workshop' started by faffi, Jul 22, 2019.

  1. faffi

    faffi A.S.A.N.

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    We have always been told that shaft final drive zap more power than chain final drive - some have claimed up to 25% loss from shafts and as little as 1% from chains - but it's a theory I have always resisted to accept since there has been little real life test results to support this claim. Bikes that were made almost identical with chain and shaft final drives, like the GS1000 and KZ1000, usually showed similar on the road performance, which they never would had one system zapped 25 times more of the power reaching the rear wheel.

    And today I stumbled upon the results shown below, showing that in fact a shaft drive ended up marginally more efficient than all the tested chain driven bikes! It would be nice to see more tests like this, as I am sure they have been made. Anyway, the next time someone tells you that shaft final drives are horribly inefficient, ask them to prove it.

    From German PS magazine, May 2008:

    Power at the crank / Power at the wheel / Power lost / Power loss in %

    BMW HP2 Sport
    133 / 125 / 8 / 6,4

    Ducati 1098 R
    183 / 167 / 16 / 8,74

    Honda Fireblade
    180 / 168 / 12 / 6,66

    Kawasaki ZX-10R
    182 / 169 / 13 / 7,14

    KTM 1190 RC8
    154 / 143 / 11 / 7,14

    Suzuki GSX-R 750
    140 / 129 / 11 / 7,86

    Suzuki GSX-R 1000
    180 / 168 / 12 / 6,66

    Yamaha YZF-R1
    176 / 163 / 13 / 6,89
     
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  3. lindsaymac

    lindsaymac Can't reMember
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    Still goin' through those old mags, huh? Thought you'd be out riding your bike in this weather.

    :)
     
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  4. faffi

    faffi A.S.A.N.

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    :D I found this online after a search, instigated by claims by (among others) Motorcyclist.com that claimed that shaft drive absorb tons more power than chains. Which they don't. Compared to a fresh and properly adjusted chain, I would expect a typical shaft to absorb from 25 to 100% more power. Which sounds like a lot, but we are talking a bit more of something rather small. And it's a far cry from the claim of up to 25 times more power absorbed that some throw around.
     
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