wrote:

I dunno nothing about bike tech so I pose
this question here... My mountain bike has
a Squeaking screeching noise whenever
I engaged back gear 3, 2 and 1. Other 4, 5
and 6 gear are all ok. I tried to figure out
what caused this noise and not sure where the
noise from. My best guess according to my
online finding is RD (rear derailed) causing
the noise. The chain and RD is not fully
engaged whenever the back gear is on from 3
to 1. Am I right or not?

Is there a noise if you hang the bike and pedal
with your hand or is it only when you sit
on it?

For sure, the chain doesn't scratch into
anything obvious along the way?

Does anything look different with 1-3 compared
to 4-6?

Does it get better/worse from 1 to 3 or is it
the same?

--
underground experts united
http://user.it.uu.se/~embe8573