> > > > "Michael Green" <
[email protected]> wrote in message
> > > >
news:[email protected]...
> > > > > My chainrings are knackered. But what are they? Shimano, triple,
no
> > > > > name (other than Shimano) on rings. Bike has Exage brakes,
downtube
> > > > > levers are marked SIS. The only unusual feature is a smooth ring outside the large ring to
> > > > > prevent your leg coverings getting
'bitten'.
> > > > > Bike is Dawes Comp. Giro 200 3-4 years old. Any help or advice welcomed.
> > > "A Muzi" <
[email protected]> wrote in message
> > news:<
[email protected]>...
> > > > Please write back with the Shimano crank part number. It's stamped
on
> > the
> > > > inside of the right arm and begins with FC, such as FC-M480 or
FC-MC20.
> > > > Shimano is rigorously thorough with this nice thoughtful feature.
> > "Michael Green" <
[email protected]> wrote in message
> >
news:[email protected]...
> > > It looks like FG TY30. And yes 3-4 years old. Bought new by me from
Dawes
> > dealer.
> "A Muzi" <
[email protected]> wrote in message
news:<
[email protected]>...
> > That makes it easy!
> > The Tourney crank you have is rivetted together and so none of the chainrings can be removed or
> > changed. When you say"knackered" are you referring to the several teeth which are truncated and
> > the slots and
folds
> > just beneath the teeth which look like a metal eating monster has chewed
it?
> > That's not a problem, it's a feature! Those things assist shifting.
Stop
> > at an LBS and peek at a similarly priced new bicycle's chainrings before
you
> > pursue this any further.
> >
> > We get telephone calls from week-old bicycle customers in a panic over
those
> > slots and folds.
"Michael Green" <
[email protected]> wrote in message
news:[email protected]...
> They are knackered, the pressure side of the teeth are very rounded, particularly on the
> granny ring.
>
> Rivetted eh? And here was me thinking the bolts were just diguised by the crud. Advice on
> replacement please! Thanks.
In that case you'll need to buy a complete crank, often the same price for a right side as for the
whole complete set. Here, that type of unit is $35~$40 complete - less than buying chainrings!
If you intend to keep the bicycle a long while, if there are no impending major repairs and if you
think you'll want custom gearing now or in the future, you might look at a more expensive crank that
allows individual ring substitution. It's likely you'll have to change to a shorter crank bearing
spindle ( "bottom bracket" assembly) so the entire operation will be quite a bit more at minimum.
If you have no other complaints than the "knackered" ( quite a colorful word!) damage, just get the
current model of your Tourney crank. Any LBS should have it and expect a five minute installation.
--
Andrew Muzi
http://www.yellowjersey.org Open every day since 1 April 1971