Yeah, for 300 lbs you need some PSI in those tires. Scary thing is sometimes tires blow off those rims kinda easily but usually that happens during inflation. Just take it easy. No 40mph curvy downhills.
On my late 50s cruiser one wheel was stout as can be, but the other had spokes rusted down to nothing - I reckon one wheel wasn't under the tarp so exposed to the elements or something like that. My wheels had huge spokes which should hold up well. If yours don't look so hot, lowrider bike shops can get you pairs of wheels for $100 if those don't hold up. There are probably other sources, but I'm just giving you an idea of cost.
Last edited by LesterOfPuppets; 02-14-11 at 02:41 PM.