bike crackles like popcorn

My wife just got a Giant OCR1 bike with a carbon fiber seat post.
There is all kinds of crackling noise (like popcorn popping) when you
move around on saddle. Is it the seat post or saddle? Do carbon fiber
seat posts make this noise. I tried tightening it, but it did not
help.
Thanks, Greg

Greg Wrote:
My wife just got a Giant OCR1 bike with a carbon fiber seat post.
There is all kinds of crackling noise (like popcorn popping) when you
move around on saddle. Is it the seat post or saddle? Do carbon fiber
seat posts make this noise. I tried tightening it, but it did not
help.
Thanks, Greg

I suggest taking the saddle off and lighly greasing the rails where
they interface the the seat post. Check for proper lubrication of the
saddle rail binder bolt(s).
I would also give everything in that seatpost area a close look... for
cracks.
Check your seat post "collar" and make sure there is proper lubrication
of the bolt and female threaded portion.
I would check with your Giant dealer on this as well as reading the
owners manual.

"Thread Preparation
There is resistance to turning the bolt, as the fastener gets tighter.
Some resistance comes from friction and rubbing between the internal
and external thread surfaces. Because of this, it is common to prepare
the threads with lubrication. This can take for form of liquid
lubrication, grease, or an anti-seize compound. Even liquid
thread-lockers provide some lubrication during tightening. As a simple
rule of thumb, if the thread size is small, such as a derailleur pinch
bolt, a liquid lubricant is adequate. If the thread is large or the
torque relatively high, such as a pedal thread or bottom bracket, use a
grease or anti-seize compound. There are situations, however, where a
manufacturer may recommend no lubrication on the fastener. If is useful
to lubricate the threads and under the head of the bolt, especially when
the bolt head is turned during tightening."

from Park Tool Repair section at URL:

http://www.parktool.com/repair_help/thread.shtml

There is a section on torque in common bicycle fasteners that you might
want to check:

http://www.parktool.com/repair_help/torque.shtml


--
daveornee

There is all kinds of crackling noise (like popcorn popping) when you
move around on saddle BRBR

grease on the saddle rails

Peter Chisholm
Vecchio's Bicicletteria
1833 Pearl St.
Boulder, CO, 80302
(303)440-3535
http://www.vecchios.com
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