Loss of a little air overnight isn't unusual...loss of more than a couple of pounds (plus a couple more for every time you put the gauge on) probably indicates a leak. Most common point of leakage is the Schrader valve's core, beneath the seat. You can check it with a little spit or soapy water, and buy a valve core wrench or replacement valve cores from your local auto pats department or store.
For those with the manual air suspension, I would say that 20 pounds is pretty low pressure for carrying a passenger. There is a table with suggested pressures in your owners manual. I'd suggest 30-40 pounds or more. It is no wonder your suspension is bottoming out. For those with the automatic aur suspension system, checking pressure under the seat is pretty meaningless....except for chasing leaks. The pressure will change whenever your Spyder is started, the parking brake released, and the Spyder put in gear. It will also change wheneve the load is changed if the above conditions are met. Merely standing on the pegs, changing the weight distribution, is enough to cause the system to adjust.
) will have some suggestions for us.
