i have a new GT bump, got it last friday. the cranks are anoying me. they are 3pc. they move left and right. its like the axle is not tight enough or somethin and they move. to get a better discription, say i grabbed the crank on either left or right side, i could push it about half a cm in and out. i wanna know if this can be solved easly or wether it is quite a serious problem and i sohlud get a bike shop to fix it?