To calculate the overall star rating and percentage breakdown by star, we do not use a simple average. Instead, our system considers things like how recent a review is and if the reviewer bought the item on Amazon. It also analyses reviews to verify trustworthiness.
I used this on a 13-year-old bike that was totally neglected, and it worked a treat. The chains are turning again and the squeaky noises are gone. Great to resurrect an old timers and go on cycling sessions with my six-years-old who has just removed his training wheels. Great product and pretty good price to resolve a niggling problem.