Mainly its because of warn down break pads, they have built in 'squeakers' to warn the driver they need replacing. usually quite loud especially when turning corners.
new pads can also squeak they just need time to wear in, check if your pad has copper grease on the back aswell, this helps. or if you've used 'back to black' etc on your tires and got some on your disks, that squeaks.
wheels can also squeak from lose wheel nuts strangely enough, i had this problem when getting new alloys and not fitting them properly.
More info: '97 Honda, the right front tire was recently patched by a tire shop. Squeak occurs when the car bounces on bumps, holes, rough road.
The brakes can squeak, the suspension can squeak, the steering can squeak, the wheel hub/bearings can squeak, have a trusted mechanic determine the source of the squeak.
Could be the belt in the tire, that can cause it to squeek, also it could be the wheel bearing or the C/V Joint.
The brake shoes may be about worn out. The wheel bearings need grease
I'm having the same problem. 98 Mountaineer. I think it's wheel bearing or possibly c/v joint. it sounds like a shredding almost, or grinding noise + squeak in the driver side front wheel hub.
Brakes
check wheel bearings!
bad wheel bearing.
I've greased that wheel, but it still has a squeak. I managed to squeak by the accident scene without a scratch.
A dry wheel bearing will cause the rear wheel to squeak at low speeds. The wheel bearing should be checked immediately to avoid a major problem.
Could be many things, such as as wheel bearing or tire, but most often it is the little warning clip rubbing on the rotor indicating that your brake pads are worn.
A Trailblazer that squeaks only when turning to the left could have a problem with the steering or front wheel bearing. Turning to the left puts the right pressure on the parts to cause them to squeak.