I don't use a wax, instead I use a paint sealant (Shimemaster) that leaves a film of protection to repel water and dirt. The product that I use is sold under the Wizards Products line and it is amazing. I have it on my DD and it sees nasty snow, rain, sun, and a lot of dirty roads. It still stands up well and is easy to apply
www.wizardsproducts.com