Hello, everybody. I tried to Google this one but couldn't find any information.

What I'm trying to determine is the maximum weight one could haul on standard 27" wheels?
My commuter/road bike is from 1980 and the wheels are the same age, standard chromed steel. Over the Winter when it'll be inappropriate to ride on 27 x 1 1/4" tires, I hope to upgrade the rims to something newer - either 27" or 700c will do, I've got the extra reach on my brakes to accommodate.

I don't want to compromise how much I can carry, and I don't want to trash my rims. On the bicycle it automatically has to carry my 150lbs self plus my gear.