I was wondering what diffrence was between shocks with cans and shocks without cans?

 

If your style of riding involves extremely hard working of the suspension, particularly in hot weather, the remote reservoirs help to prevent fading of the shocks due to heat build-up in the body of the shock. The gas is removed from the shock body via the remotes, thereby keeping it cooler.

 

Is this "can" replaceable? I have FOX shocks and it seems the back end is getting a little soft. Do I replace the can or the whole shock?

 

The cheapest route would be to have it recharged. Any descent bike shop should be able to handle that at a very low cost....

It may need rebuilt, new seals, oil and charged, you may even have the valving changed at that time. That shouldn't be all that expensive either...