Surely if you've taken it upon you're self to have a rear spocket made, you've passed the insights to others? We've tested various coatings and materials over a long period of time. What you think is a cure, we may think won't last! All of the upgrades ( although sometimes late) have been done at cost price in an effort to help owners. We have never turned away from a ptoblem and always try to resolve any issue. This is why i don't post every often, forums get emotional and emotive, there are 180 jobs and over 100 years of history. Mark