If you are in the market to purchase a mountain bike then you might already know that it is not easy besides it is very time consuming.  If you keep two important things in mind, you shall be able to purchase the perfect mountain bike which will always give you a trouble free ride.  They are the sizing and the frame.  It must be in accordance with the size of your body.  Factors such as metal type, and technical features should never take precedence over the bikes size.  Before selecting a bike, you should take the inseam measurement.  The inseam should be determined taking the seating of the bike into consideration.  The inseam of your tracking will not give the relevant measurement.  Place your back against the wall, place a measurement tape between your legs while distancing your feet between 6 to 8 inches from each other.  Lift the object until it adjusts into the crotch similar to a mountain bikes would and mark this length on the wall with someone else assistance.  The inseam of your mountain bike must be equal to the length between the floor and the marking on the wall.  The next criterion is the assessment of the frame size.  You may measure from middle to the top or from middle to middle.  This can not be precise because deviation can lead to imprecise fitting.  The mountain bikes do carry adjustable seat tube and adjustable handlebar tube.  Unfortunately imprecise measurement can end up making cycling uncomfortable.  Time and patience is the secret to attaining the right adjustment.  Mountain bikes sizing can best be judged when it is in standstill position.  You need to keep the rear wheel above the ground using the bike's stand.  The top bar of the bike must be parallel to the ground and to achieve this the front of the bike should also be above the ground.  Place your foot on the pedal and make sure that the knee is in line with the pedal while keeping the pedal in the same level.  Most bikes allows you to attain this position by adjusting the seat forward and rearward.  Even thought the work put in to decide on the right bike sizing takes time the final outcome will give you a mountain bike which will make you believe it is a part of your body.  And riding this bike will be easy on even, uneven, or rough tracks.