A CrossThread Question

ayers said:

Hello, I have recently gotten my first road bike and have a question.
I know you aren't supposed to ride with the chain in the biggest front
sprocket and the biggest rear cog. And the smallest front sprocket and
the smallest rear cog.
I have a triple front crank (52/42/30) and a 9 speed rear cassette (12-26).
My question is this: If I am in the middle front gear, what is the
smallest rear gear I should be in? Right now when I get into the 6th or
7th rear gear it shifts hard and makes a lot of noise. I can get into
the largest rear gear with no problem. Is this normal or does it need
some adjusting?
Thanks for any advice you can give me.

I personally have never any trouble in using all combinations, although
I read warnings in some manuals. I have both Campy Record and Shimano
Ultegra on my bikes and would be disappointed if I could not use all
combinations. I use tripples with the widest range standard cassettes,
and would be surprised to learn that doubles are somehow worse.

My guess is that you have not tensioned things correctly.

--
Bob Wheeler --- http://www.bobwheeler.com/
ECHIP, Inc. ---
Randomness comes in bunches.

ayers said:

Hello, I have recently gotten my first road bike and have a question.
I know you aren't supposed to ride with the chain in the biggest front
sprocket and the biggest rear cog. And the smallest front sprocket and
the smallest rear cog.
I have a triple front crank (52/42/30) and a 9 speed rear cassette
(12-26). My question is this: If I am in the middle front gear, what
is the smallest rear gear I should be in? Right now when I get into
the 6th or 7th rear gear it shifts hard and makes a lot of noise. I
can get into
the largest rear gear with no problem. Is this normal or does it need
some adjusting?
Thanks for any advice you can give me.

You should be able to use ALL the rear cogs while in the middle ring. Your
front derailleur should be able to "trim" its position to alleviate those
rubbing sounds; if it can't then your cable tension needs adjusting.

Check Sheldon Brown's site for instructions, or have your LBS show you how
to set it up right.

Good luck.

Bill

Bill S. has good advice. Your title to your problem would be better
if entitled Cross Chaining which causes premature chain stretch as well
as unwanted noises due to chain rubbing on front derailler cage ( and
sometimes rear derailler rubbing). The chain likes to run as parallal
as possible to the chain rings and cogs. The extreme gear use, i.e.
cross chaining, will have the chain come off the front chain ring
parallal to the chain ring(s) but then have to make a bend,
diagonally, to get to that extreme rear cog before it does another bend
to become parallal to the rear cog(s). See my crude diagram below. You
may use the extreme gears in extreme conditions as all gears should be
availabe to us when needed but know the price you are paying if using
those extreme combinations for too long. An extreme condition might be
a head wind and the only gear you feel efficient in is one of those
cross chained gears.
1 (front CR)
\ (chain bending)
1 (rear cog)

<[email hidden]> wrote: (clip) An extreme condition might be a
head wind and the only gear you feel efficient in is one of those cross
chained gears.(clip)
^^^^^^^^^^^^^^^^
I don't see it. Cross chaining does not produce any ratios that are beyong
the range available with proper alignment. Mostly, I believe, cross
chaining results from ignorance or forgetfulness. An example of
forgetfulness would be, for example--you are in your big chainring, and you
keep downshifting in the rear without counting, and you wind up totally
crossed.