Knocking Sound in Right Front Wheel

This is a long shot, but I thought I'd ask.

My 98 Sentra GXE I recently bought, occasionally when I turn the wheels from sharp left to sharp right (such as when backing out of a parking spot) I will hear a knocking sound from the front right wheel. It sounds like running over something, or perhaps like the hubcap just came loose. It usually only happens when I JUST turned the car on and started driving, and wont happen after it's warmed up.

I had my mechanic friend glance at it in the parking lot after church, he was stumped. He said it's the sound he would normally associate with a broken boot? or axel, but they both look ok. He said he'd normally hear that sound frequently if the boot? was cracked and completely dry of oil/fluid?, but since it's so intermittant he doubts it's that.

I havent put it in the shop yet, and might not if it doesnt get any worse. The car rides fine, I dont notice any problems other than the sound. The wheel doesnt wobble or anything.

Any theories?

it could be a bad C/V joint. just because the boot is intact doesn't mean you don't ahve a problem with the joint.

I have a 99 Suzuki Esteem, it makes the same kind of noise but only when I put the car through through a lot of sideways G's like going around a sharp corner at 20 mph. It kind of sounds like it would if I were lightly taping on a pine 2x4 board with a hammer.

Only, in my case, the boots are bad, I know they are bad (cracked in half all the way around), water and who knows what else has gotten in there and probably nearly destroyed the grease, but we need the car running more than we need it down for three days while I tear it apart. But eventually I will have to take care of it.

Anyway, I agree with JudoJohn it is probably a bad CV joint.

CV joints seems to be the consensus