Is there any difference between rear air shock and coil shock on a Mountain bike?
Air or coil are both potentially good shocks. An air shock is more tuneable, where a coil shock is less tunable but potentially more reliable. The spring rate on a coil shock will need to be matched with your riding weight (you with gear i.e. full camelbak) just like your air pressure should be matched with your riding weight. You can switch out most rear shocks as long as the eye to eye (bolt holes) length is the same. Ebay has lots of rear shocks that people have taken off to upgrade. You can also have the shocks serviced to be tuned to your weight and riding style. Push industries is a great place that can tune your forks and shocks, they can also upgrade it for a little more as well. Usually cheaper than a new shock that may or may not fit your frame correctly. So I would only buy a bike that has a shock that is serviceable.
