Chain skipping on large chain ring.

On Sun, 14 Aug 2005 00:12:49 GMT, wrote:

There being 5-bolts on the kind of CW I use, rotating them is an
imprecise art since 90 degrees is the desired rotation and that isn't
available.

How imprecise is it to simply rotate by one bolt every so often? The goal
is long-term spread of wear across as much of the chainring as possible,
not getting it to points at right angles to the last wear. Rotating by 90
degrees at a time would get you less even distribution -- Given that wear
is symmetrical (I suppose it isn't quite, due to the spindle being between
the left crank and it), a 4-bolt attachment will allow you to spread the
wear on a chainring to just two different locations since there are two
opposite but equivalent orientations, and a 5 bolt will allow you to
spread it to 5 different orientations. I don't think it matters hugely in
practice, though.


Jasper

On Mon, 15 Aug 2005 02:42:15 GMT, wrote:

There are many interesting considerations, such as
that of only one pawl of a freewheel bearing nearly all the load,
regardless of how many pawls the manufacturer put there under the
belief that they share the load.

You mean because the load comes in on approximately one point of the
housing, rather than spread across the whole housing? If you assume the
whole outer housing takes equal share of the load, then sheer elasticity
should get more than one of the pawls engaged, until the pressure over the
lot is small enough that it doesn't happen any more.

An interesting experiment would be to take one of the teeth that the pawls
ratchet against, and make it slightly larger, so that when it is engaged,
none of the other teeth are. After a sufficient number of miles, I would
think that the slightly larger tooth would have worn faster, until the
point where multiple teeth are again engaged as a matter of course.

Jasper

On 15 Aug 2005 14:43:04 -0700, "Marvin" wrote:

Actually, I checked this with some suitable old/new bikes today. About
eight teeth on a new 48t chainring take obvious tension, and with a
worn-out chain two, maybe three teeth. It should be obvious that wear
on everything will be a lot faster when the load per tooth (or per
chain link) is around 8/3 times greater.

Now try an older chainring with a new chain. This is the permutation that
matters, and I'd like to hear your result.

Jasper