This is simply a wrong comparison. Metal is
NOT plasticine, whose physics properties are a lot different. Plasticine
seems larger due to it can be slightly less dense. In fact the volume doesn't change, but its surface area changes. In comparison, the roller can't be less dense, except corrosion or oxidation, which is another story.
Krzysio wrote: ↑Thu Mar 30, 2023 5:31 pm
Take a bit of plasticine, roll it and you'll se how worn roller can have larger diameter, than new one
Worn rollers
do lose material, which has been well studied by CS, ZFC, Silca, etc, but not major.
Krzysio wrote: ↑Thu Mar 30, 2023 5:31 pm
Worn rollers will basicaly not lose material.
I agree, but here you are contradictory to the first point "larger diameter". Pressure on surface squeeze the metal or make a dent, etc. It doesn't make it larger. ZFC has a lot of pictures showing the deformation/dent. Objects prefer staying at its lowest potential energy, and in the driving system, the dent/deforming part of the roller has a lower potential during the dynamics, which makes the contact area smaller.
Krzysio wrote: ↑Thu Mar 30, 2023 5:31 pm
They get worn significantly by being rolled with presure
Agree, the worn pin elongates the chain.
Krzysio wrote: ↑Thu Mar 30, 2023 5:31 pm
Pins are abraded, and this, and only this elongates chain.
Links do elongate under optical microscopy, due to creep, but it contributes negligibly to elongation compared to wearing down of the pin.
Krzysio wrote: ↑Thu Mar 30, 2023 5:31 pm
Unless someone will report links elongation.