Shimano REAMED for Engineering Incompetence

This is an engineering overview of the spate of Shimano cranks that have been failing in recent times. This has mainly affected Dura Ace and Ultegra cranks which use a two part crank arm that has been glued (bonded) along its seams. The primary failure mode is via corrosion but it appears this has been accelerated and made significantly worse by using a Steel axle into an aluminium spider. The aluminum close to the steel axle appears to have been preferentially attacked by galvanic corrosion. As the corrosion has set in, the expansion in the material has forced the glue joint to break. It does not appear the glue has failed on it's own accord. ***there is an error in the presentation where I stated 105 was welded. I am now informed it is hollow forged. In the grand scheme of things it doesn't seem to matter as that unit is not affected. *** Webpage with additional graphics and pictures https://www.hambini.com/shimano-crank... Patreon - exclusive content and see things first   / hambini   Social Media https://www.hambini.com Hambini Website   / hambinieng   Hambini Instragram   / hambini-engineering-109615891445939   Hambini Facebook