Jockey Wheel Question

[SuprF1y]

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

 

[alfeng]

Originally Posted by SuprF1y .

... do I need to replace them ([COLOR= #808080]jockey wheels[/COLOR]) 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?

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 ([COLOR= #808080]as found on the 9-speed-and-later Dura Ace & Ultegra rear derailleurs[/COLOR])
• 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.

 

[SuprF1y]

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