ok, on my new 4900, which has the rapid fire type shifters, doenst shift a lot of the times. this mostly happens on the front cog/gear. ex:i upshift and all that happens is a loud grinding noise that announces that something went wrong. am i shifting wrong or is something in my gears, shifters etc wrong?

Sounds like the derailleurs need to be adjusted. This is usually common maintenance that either the bike shop does when you take the bike in for a tune-up, or it is not something that is too hard to do for yourself. Parktool.com for a good bike repair info place. It tells you how to adjust the derailleurs and mess with the shifters and pretty much anything elso you would ever need to know.

Take........it.............back.............to..........where...............you.............bought.. ...........it...............from................

This happens with ALL new bikes. The cables have to "set". A shifter and brake cable is a bunch of thin wires banded together. After a few uses, the cables will "stretch". The wires are tightened due to the tension of shifting. This tightening increases the overall length.

The shop from which you bought your bike should have included a free 30 day tune-up. If not, go back and ask for one. It's standard practice to provide one free initial tune up.

L8R