how do you know if sprocket is worn?
bicyclette
new chain skips on one particular sprocket (6th gear) on MTB.
Terry Morse
> Hi, Is there a way to inspect a sprocket to see if it is too worn? My
> new chain skips on one particular sprocket (6th gear) on MTB.
Everything you need to know about sprocket wear, including photos:
http://www.sheldonbrown.com/chains.html#wear
--
terry morse Palo Alto, CA http://bike.terrymorse.com/
Chris Zacho The Wheelman
chech the teeth. If there is a noticible "hook" on one edge, it will
soon need replacing.
On the older cogs, before they came with broken teeth and handicap
ramps, you could remove the cog, flip it over and use the other edge of
the teeth, giving the cog a few hundredd miles more life.
Alas, fashion and "hype" have done away with this.
- -
"May you have the wind at your back.
And a really low gear for the hills!"
Chris Zacho ~ "Your Friendly Neighborhood Wheelman"
Chris'Z Corner
http://www.geocities.com/czcorner
MSeries
> Hi, Is there a way to inspect a sprocket to see if it is too worn? My
> new chain skips on one particular sprocket (6th gear) on MTB.
I had that problem and replaced the offending sprockets, the problem was
fixed.
Carl Fogel
> Hi, Is there a way to inspect a sprocket to see if it is too worn? My
> new chain skips on one particular sprocket (6th gear) on MTB.
Dear Ed,
I suffered similar problems for years on an
old bike with a 12-tooth rear. Whenever the
pedals began to skip in high gear (which was
used about 80% of the time), I'd replace the
cog, and the problem would vanish. It was a
Sachs Aris cog and rarely lasted six months.
One of the happy side-effects of a new bike
was that the even smaller Shimano 11-tooth
cogs last forever in comparison.
Skipping problems tend to be in the smaller
rear cogs because they're coiling the chain
at tighter angles and there's less tension
from the relaxed derailleur spring.
The smaller cogs wear more, too, because they
spread the load over fewer teeth.
You might spend more time in this 6th gear
than the gears right next to it. Or it might
have suffered a broken tooth, weird wear, or
metallic caries.
In general, when a new chain skips, it's a
light-hearted cog that you should kiss goodbye.
The skipping itself constitutes the inspection.
Carl Fogel
dvt
> On the older cogs, before they came with broken teeth and handicap
> ramps, you could remove the cog, flip it over and use the other edge of
> the teeth, giving the cog a few hundredd miles more life.
That was a neat feature. I like the term "handicap ramps," too.
> Alas, fashion and "hype" have done away with this.
IMO, it's more than fashion and hype. When I switched from straight cogs
to those with handicap ramps (Suntour PowerFlo, perhaps?), my shifting
was *greatly* improved. I'll deal with 1/2 the lifespan for the
improvement in shifting. YMMV.
--
Dave
dvt at psu dot edu
jobst....@stanfordalumni.org
> Hi, Is there a way to inspect a sprocket to see if it is too worn?
> My new chain skips on one particular sprocket (6th gear) on MTB.
That's the test. If it skips under load randomly whenever pedaling
hard, its the sprocket. If the chain skips approximately once every
time the chain makes one complete revolution, it's a tight or an
unlubricated link in the chain.
The way to test for a tight link is to manually turn the derailleur
idlers so the chain is semi slack and turn the cranks backwards. A
tight link will remain angled when it comes of the derailleur wheel as
it moves forward on the bottom run of the chain.
To fix a tight link, bend the chain sideways forcefully, an action
that tends to spread the side plates and increase clearance. Using a
super-link gets around this problem. In fact most people don't push
in pins on their bicycles so tight links are not so common a problem
anymore.
Jobst Brandt
jobst....@stanfordalumni.org