Jockey Wheel Question

Discussion in 'Cycling Equipment' started by SuprF1y, Mar 5, 2012.

  1. SuprF1y

    SuprF1y New Member

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    Hi,
    I am replacing my old 8 speed drivetrain. I figured I'd get some Jockey wheels along with the cassette, rings and chain.
    I discovered my XTR rear derailleur jockey wheels have 11 teeth. The wheels I see online for 8 speed have 10 teeth whereas the 9/10 speed have 11 teeth.
    I have ordered the other 8 speed parts. Should I get 8 or 9 speed jockey wheels? I would prefer the 10 teeth 8 speed as I figure it will match the chain better but I'm worried it won't fit the derailleur as the replacements are described as being for "8 speed derailleurs" although I don't think derailleurs actually have speeds do they - it's all in the shifters.
    The other question is do I need to replace them at all? They don't seem in particularly bad shape but they're about 8 years old. Do you normally replace them with the rest of the drivetrain?
    Thanks,
    Will
     
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  2. alfeng

    alfeng Well-Known Member

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    You do NOT need to change the pulley wheels ...

    Beyond the 11t pulley wheels on the XTR RD-952, the difference between the 8-speed XTR RD-950 and the 9-speed XTR RD-952 is mostly cosmetic ...

    • the derailleur hanger bolt on the RD-952 is slightly recessed (as found on the 9-speed-and-later Dura Ace & Ultegra rear derailleurs)
    • the pulley cage on the RD-952 only seems to have been available in the SGS length whereas it was availaabe in three lengths on the older RD-950
    • some RD-952 cages may have been silk screened with the 'Mega-9' logo

    In theory, the chain will create less friction with an 11t pulley wheel than with a 10t pulley wheel ...

    BUT, there is so little friction in the pulley wheels (IMO) unless their bearing/bushings need to be lubed that it probably only matters if you are trying to limit the loss of energy due to fricton.
     
  3. SuprF1y

    SuprF1y New Member

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    Cool. Thanks for the detailed response.
    I think I'll just leave them as they are then.
    Cheers,
    Will
     
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