I've got a set of those Weinmans on my '77 Schwinn Traveller. Spring for a new freewheel, chain, and brake pads. They aren't that expensive, and you will be rewarded with a drive train that is smooth and quiet.
Currently have about 5000 miles on the Wienmans. I installed them right out of the box and they stayed straight. The LBS tightened them up about 1000 miles ago, as part of a tune-up. At that time, they were about 3mm out of true.
I weigh 250, and they do rub the pads just a little when standing and mashing the pedals while leaning the bike to the side.
Very happy with product/price. I would buy them again.