The bike bug uses delrin. My drive wheel last about a 1,000miles on that kit. I heard that another company based in florida builds there engines for em and they just put there own sticker on it. is that true? and who is the other company? Bike bug has been around since the 60's so those engines must be good for bike bug to sell them as a new and improved model. I bought one last year and its proven itself worthy in my book to be called a reliable kit!