what kinds of components do i need for my mtb?

Most mountain bikes have Shimano shifters & derailleurs. SRAM is the other main vendor. Shimano makes a wide range. Below are some models of Shimano rear derailleurs.

SHIMANO TOURNEY -  Mainly designed for riding around the neighborhood.

SHIMANO ALTUS - Sufficient for paved or very easy trails; avoid hills.

SHIMANO ACERA - Slightly better, but won't shift well under stress; capable for easy casual riding.

SHIMANO ALIVIO - Minimal capable for recreational riding; will handle some hard riding.


SHIMANO STX / DEORE - Entry-level components for hard riding; tough & reliable.


SHIMANO LX - The minimum standard for hard riding. Reliable & responsive.


SHIMANO XT - More responsive than LX, but still reasonable tough.


SHIMANO XTR - Light, responsive racing components; tend to be quite expensive; often sacrifices toughness for responsiveness.


Look for a component set that fits your expected riding style.