No spare, boat goes from garage to ramp to river. Many years ago, we had problems with the tires as they always looked inflated. Well, since the trailer tires were so many ply, they looked great but had zip for pressure! Wore the shit out of them on a long drive! Just stupid on our part...hubs were checked, everything else, but not pressure!!!
I got some of these little gems to keep a quick eyeball on the tire pressure:
Indicator Caps (http://cgi.ebay.com/ebaymotors/ws/eB...category=33746)
Another option (http://store.yahoo.com/eagleday/vitiprin.html)