When I pedal forcing a little with my right leg, the bike makes a noise that I don't know how to describe. I'll try to do it. It's like:


a short "ting"
a tiny bell
if a small rock hits the down tube


I don't know what is causing this noise, but I think that it could be any of this things:


pedal
crank arm/pedal connection
crankset


I think the material of all these things is alluminium.

I don't feel anything (like a bad shifted chain) when I hear the noise.

It happens when there is movement and when there is NO movement (I use the brake, so the bike doesn'e move, stand using all weight on right pedal, and it makes the noise)

The pedals could be in any position, It is not in a particular position. Just pressing the right pedal.

Has someone else has this "problem"? Any ideas of where this comes from?

Update:
Yesterday I took out the chain and stood on the right pedal, and made the noise. Then is not the chain, nor the transmission system.

I put oil in the pedal axis, but had no luck. Also tried to loose the pedal, but the juncture point is too tight, and I couldn't.

Today I will try to use oil in the bottom bracket.

Update: here is a link to info on the bike http://www.diamondback.com/2012-sorrento maybe it helps to know the model of all the components.


Question: Prove that expression is integer
Answer: It equals
$$
\binom{2m}{m+k}\frac{3m-1-2k^2}{2m-1}=-(m-1)\binom{2m}{m+k}+4m\binom{2m-2}{m+k-1}.
$$
I got it by expanding $3m-1-2k^2=2(m^2-k^2)-(2m^2-3m+1)=2(m-k)(m+k)-(2m-1)(m-1)$.