I'm looking at getting a Mongoose Massif which I believe is a 2003 model. It is dually with a sid rear shock and Duke front. I checked some tech documents on the shock and it said max air pressure was 250. How does that translate to rider weight. Does that mean a max rider weight of 250. Also I think I remember something about a blow off, does that mean that the shock will blow out air before the seals blow?

The air pressure needed for different rider weights will vary based on the bikes suspension design. Using the same shock for two different bikes, rider weighing 175 pounds. On bike a the shock may require 125 psi. On bike b the shock may require 175 pounds.

The blow off could be for when the shock is locked out, if it hits a hard enough bump it will work anyway.

Hope this makes sense.