Something loose inside front wheel?
 

There is a noise coming from the rim of my Mavic Ksyrium Equipe front wheel. It sounds like something is loose there. That thing seems to be restricted to about 2-3 inches (doesn't move around) of the rim and the noise is audible at low speed only after each rotation of the wheel.

What could it be?

When rims are drilled the shavings fall into the rim. Rim factories shake these out but sometimes miss one or two, or a shaving may still be attached, and break off after the wheel is ridden, and rattle around. The giveaway for a loose shaving is that you can hear it rattle when you shake the wheel or ride at very low speed, but faster speed forces it out against the periphery where it stays silent until you slow down again.

If you're patient, you can sometimes shake it out of single eyelet rims, but double eyelets make it almost impossible.

If it bothers you, and you can't shake it out, locate it by shaking, drill a tiny hole on the tire side of the rim and inject a drop of a glue like rim cement,. or stiff grease That'll keep it in place, and cure the rattle. Otherwise, either learn to live with it or ride faster.

The noise does not bother me too much. I am more concerned about any impact on short/long term safety.

Thanks for your help.

As long as it's just a shaving, or a prank by one of your riding buddies, there's no safety issue at all. Next time the tire is off see if you can shake it out.

My Ksyrium Elite's have 'fore' drilling--no spoke holes on the tire side of the rim. If the Equipe's are the same, you might have to dismount the tire and tube in order to attempt removing any debris. The big advantage of this setup is NOT having to use rim strips!