I have a giant mountain bike brand new I bought it a week or so ago. At first the brakes where new and needed to be used. I use this bike to get to work and back about 8 miles. The front disc seems to be rubbing some where cuz I get some vibrations while I ride. I have taken it to the shop to get the wheel put on right but they said it was fine and not rubbing could this be something else??? Enjoy your ride

Mystery rubbing such as this are pretty much impossible to diagnose over the web. You need to start by helping yourself. Hang the bike up or even flip it over onto the bars and seat and then locate the source yourself.

Also a slightly scuffing disc brake does not cause vibration. If you've got some sort of shudder coming up through the bars while not applying the brakes then it's due to something totally non related to brakes. If the shudder occurs when you're applying the brakes then that's different. In that case your calipers may need to be adjusted or you may have a brand that comes with stock pads that are not happy with being wet. Full organic pads seem to like to squeal or shudder when wet. The ones with some sintered metal in them seem to do this less.

Yes it could be something else, most like the vibration of the mtn tread on pavement. But I couldn't say based on what you've posted. if it helps, disc rub has a certain chirpy sound, you might duplicate it by applying the brakes ever so slightly as you ride and seeing it that's what you hear or feel.

Otherwise, I'd assume the shop knows what they're doing (thought that's not always true). If you're going to ride this mainly on pavement you might consider new tires with a smooth tread, or at least a center ridge if for mixed pavement and dirt. This will not only reduce vibration, but greatly reduce the rolling resistance for an easier ride.

Pardon the dig at the shop, but if they asked (which they should have) and you said it was for pavement or commuting, they should have spoken to you about more appropriate tires and suggested a change at the time of sale.

Yeah That is true. I guess I'm pretty sure its the brakes because it happens only during I ride. Also It makes a nosie kinda like something scraping. I have been looking into it but the brakes are working fine. I don't really know what I should do. I don't know if the guy at the shop really knows what they are doing sence when I bought the bike only a few mile later I found out my front and rear tire were not on very tight and began to wobble. I bet if I asked them about it they would come up with some reason why and not really say oh yeah I should tighten them more before I sell them. Maybe they are to lazy who knows the real reason why the didn't.

Flip the bike over or ask a friend to hold the front wheel off the floor. Spin the front wheel and listen carefully right at the brake. If you think it's the brake you can slide a strip of paper between the disc and brake shoe and spin the wheel while holding the piece very gently. If it's rubbing the motion will eject the paper. Don't forget to do this on both sides of the disc.

BTW- a tiny bit of chirping from a very light rub won't hurt anything, but the shop should be able to get it to zero on a new bike.

As long as the noise is pretty consistent, I'd bring the bike to the shop and ride back and forth in front of the mechanic so he can hear the noise. At least then, you know you're talking about the same thing.