I bought a new Renegade TR4 in June and noticed yesterday that the serving is getting frayed pretty bad on the bottom cam. Is this a common problem on single cam bows, or is there something wrong that I should be looking at. I shoot maybe 35 to 40 arrows a night,

Get your serving replaced.

if you're talking about 3 inches above the cam, where it takes the hard roll, yes, its common. push it back down with your thumb. there are a lot of string and cable makers on archerytalk.com that do great work for great prices. if your string isn't damaged, which it probably isn't, just keep pushing it back down every so often, if it keeps it up, until after season and get a new one, or get someone to re-wrap it.

Although I've never had a real problem with my serving unwrapping, I have heard that string manufacutres tend to slack in that region. It might be best if you go to a pro shop and get it reserved.

Serving fray happens on every bow...especially around the cams...the serving is there to prevent wear on the string, and it sounds like it's doing it's job in your case.