Originally Posted by zoridog
Condition is everything. You could probably carry 75# plus your 150 lbs if the wheels are true, spokes properly tensioned and the hubs are good.
Strength is the least of your worries. Chromed steel wheels don't stop well in wet weather. Get (at least) a new front wheel with an aluminum rim. You can get a decent wheelset in 27" (or 700) from Harris Cyclery for about $130 with sealed bearings and aluminum rims. They also have ball bearing hubs for $100.
I give my steel wheels to people who leave their bikes at their beach houses.
Yeah, they do get quite slippery in the wet weather, however they'll last the season I think and it'll be easier for me to afford them in a few months before the Spring comes and the crap gets off the roads.
So, it seems I shouldn't worry too much about the loading weight judging by the responses. I can't imagine having 75 lbs of stuff to carry any sort of distance.