[email protected] wrote:
> On Tue, 18 May 2004 12:56:57 GMT, John Everett
> <
[email protected]> wrote:
>> On Mon, 17 May 2004 13:48:09 -0700, "Mike Rocket J.
>> Squirrel Elliott"
>> <
[email protected]>
>> wrote:
>>>
[email protected] wrote:
>>>> On Mon, 17 May 2004 12:52:05 -0700, "Mike Rocket J.
>>>> Squirrel Elliott"
>>>> <
[email protected]>
>>>> wrote:
>>>>> My Ultegra RD's jockey wheels started squealing a
>>>>> couple weeks ago. I applied what I had on hand, some
>>>>> Boeshield, which quieted them down. But I wonder what
>>>>> is considered an appropriate lube for these ceramic
>>>>> bearings.
>>>> Assuming an oiled chain, we'd better hope that chain
>>>> oil is an acceptable lube for the pulleys that the
>>>> chain runs over.
>>> Good point.
>> Good point if the chain is actually oiled, but what about
>> all the people who use something like White Lightning or
>> some other wax based lube. Also, even if the chain is
>> oiled, by what mechanism does the oil find its way into
>> the ceramic bushing? There are those little rubber seals
>> that are supposed to keep dirt (and other stuff, like
>> oil?) from penetrating the bushing.
>> To get back to the original question, I use motor oil.
>> About every other time I clean and rewax a chain I remove
>> the jockey wheels, clean them thoroughly, lube the
>> bushings with a drop of Mobil 1, and replace. Some of my
>> jockey wheels have lasted tens of thousands of miles.
> If oil were somehow bad for ceramic bearings, it's
> unlikely that they would be used near bicycle chains. I
> may be mistaken, but I think that chain wax is used by a
> small minority of riders compared to oil.
> An oil film might reduce the anti-friction qualities of a
> dry ceramic bearing, but I suspect that there's no
> practical difference on bicycle chain pulleys for two
> reasons.
> First, there's scarcely any pulley drag discernable by a
> rider, so any slight increase or reduction is probably on
> the order of trimming your moustache to reduce wind drag.
> Second, the road doesn't provide lab conditions, so there
> will be dust in the bearing. The seals on pulleys are
> unlikely to be true seals. That is, I expect that they're
> just rubber washers that mean well, but which are not true
> seals--if you open the bearings after a month of riding, I
> expect that they'll be noticeably dirty and oily.
> Peter's suggestion to use grease seems quite reasonable. I
> was startled by his warning that the rubber seals may
> cause the pulleys to unscrew
> Since pulley gears on bicycles are free-spinning idlers,
> their bearings should last remarkably well. Plastic pulley
> gears eventually wear to to wicked points under steel
> chains covered with road dust.
> Out of curiosity, why do you oil your pulley bearings
> instead of waxing them like your chain? I'm not arguing
> wax versus oil, just wondering if there's something
> besides habit or convenience involved. Have you ever tried
> wax in the pulleys?
On my mountain bike, the pulleys frequently get gunked up
and don't spin freely. Dirt and oil mixture from the chain
gets washed in there. This is usually the culprit when I
have shifting problems. These days I wind up cleaning my
pulleys every time I do my chain. Not so with the (Ultegra)
road bike -- in 6 months haven't had to clean them yet.
I thought ceramic pulleys were supposed to be self-
lubricating. My XT pulleys have little white ceramic
bushings. ISTR Shimano making a fuss about these being
maintenance free when they came out. I'm sure lube doesn't
hurt, but I don't think it's necessary.
It seems to me all you need to do with your pulleys is keep
them clean. Otherwise, grease seems most appropriate, as
Peter suggests.
Matt O.
