Hmm - that doesn't sound right, and it's not something I've experienced. The bump should show all over the object - try changing the texture mapping mode or increasing the bump value. That's the only things I can think of at the moment. There's no reason why it shouldn't show all over.  The only time it won't is if you have the texture mapping mode set to object side, top or front (see image), or if the lighting isn't right.  Perhaps someone else may have some ideas.

Beginners tutorials for Bryce

Bryce Arena