Originally Posted by
grolby
Fenders will do precisely nothing to protect your bottom bracket. Doesn't mean they're a bad idea, but in general buying fenders with the expectation of reducing maintenance is misguided, except probably the headset. When you say you cleaned the bottom bracket, what do you mean? Did you pull out the bearings and install new ones? Because that's not generally worthwhile with a GXP or other sealed outboard bearing BB.
Full-coverage fenders certainly help keep you more comfortable, but I'm always surprised anyone seriously argues that they keep the drivetrain cleaner. In my experience, pretty much everything at hub level or below still gets pretty gross. Maybe it's not as bad, but it's really a difference of degree.
Look at the pictures of how "clean" fenders keep bicycles in
this thread. After seeing the pictures, I really have to question just what fenders
are good for. They obviously don't keep the drivetrain clean and the some of the pictures so that they don't do that good a job of keeping anything else clean. I've used them in the past during the winter but I really am wondering why I bother. Frankly, even with fenders on the bike, I've noticed that my glasses, face and chest are covered with road grit as is the drivetrain. Sure my bike isn't but it seems like a lot of bother to go through to keep my back dry.