lateral movement in front chainrings

Hi,

Just wondering how serious this was? The whole chainring / spider has slight
left to right movement when you rotate the crank. I've removed the
chainrings themselves to have a look, and they're ok. Crank seems tight too.

Am i going to have to remove / replace the whole bottom bracket? Any
thoughts anyone?

Cheers,
Phil

Before there were modern components, you just tightened up the bearings
a little and then back off slightly. I have no idea if modern BBs
have an adjustment even. Mine does.

Leave it slightly loose out of respect for its having worn unevenly,
otherwise the bearings won't last long.
--
Ron Hardin


On the internet, nobody knows you're a jerk.

On Sun, 27 Jun 2004 22:20:33 +0100, "Philip Egan"
wrote:

Hi,

Just wondering how serious this was? The whole chainring / spider has slight
left to right movement when you rotate the crank. I've removed the
chainrings themselves to have a look, and they're ok. Crank seems tight too.

Am i going to have to remove / replace the whole bottom bracket? Any
thoughts anyone?

Cheers,
Phil


Do you mean that the chainrings appear to wobble left to right as you
spin the crank? Is this consistent- same spot on the chainring
wobbling each time?

When you remove the chainrings, can you see any wobble at the end of
each spider arm with respect to each other? Use the derailleur cage as
a marker and check carefully.

I fixed a chainring wobble by bending the tabs at the end of the
spider arms on the crank itself. I used a large adjustable/crescent
wrench and very lightly moved the appropriate tabs in or out. Using a
black clamped to the downtube and claipers I was able to get each tab
within .003" of each other....

As usual, Sheldon Brown has laid this all out much better than I ever
will-

http://www.sheldonbrown.com/straighten_chw.html

On Sun, 27 Jun 2004 22:20:33 +0100, "Philip Egan"
wrote:

Hi,

Just wondering how serious this was? The whole chainring / spider has slight
left to right movement when you rotate the crank. I've removed the
chainrings themselves to have a look, and they're ok. Crank seems tight too.

Am i going to have to remove / replace the whole bottom bracket? Any
thoughts anyone?

If it's cyclic and constant with crank rotation, the crank is not
square with the BB shaft; this is often a sign that the square taper
is slightly wallowed or that the right crank may be bent. If it's
side-to-side slop that can be observed without rotating the crank,
then the BB is probably loose, worn, or in need of adjustment,
depending on the design.

--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Surrealism is a pectinated ranzel.

Thanks for all the replies!

Regards,
Phil


"Philip Egan" wrote in message
...
Hi,

Just wondering how serious this was? The whole chainring / spider has
slight
left to right movement when you rotate the crank. I've removed the
chainrings themselves to have a look, and they're ok. Crank seems tight
too.

Am i going to have to remove / replace the whole bottom bracket? Any
thoughts anyone?

Cheers,
Phil