After going down a long steep hill with the Bendix 70 coaster-equipped Schwinn LeTour, I pulled into a parking lot to see how hot the brake hub might actually be. I figured it would be warm, but when I put my finger on the hub it was actually very, very hot. I took some gobs of hard-packed snow that had been plowed up at the side of the lot and started putting them on the hub, and it melted them like butter in a frying pan, very quickly. I did this about five times, and could have kept at it but I had a ride to finish. So I got back on the bike and continued to head down the long grade that stretches from I-90 north on US Rt19 to Lake Erie. I kept the speed down, but I had to ride the brake a lot and figured it was getting a really good workout. As a rider with all my winter gear I weigh in at a bit over 220 pounds, plus at least another 20 for the bike which has 27" wheels, and that is a big load for a small coaster brake.
After this ride I have decided not to use this bike for any more long rides that include big altitude changes. I figure it was just not designed for this much of a work-load, and I don't want to end up getting stranded or have a crash if it burns out or fails from this great heat generated. I will have enough fun just cruising around town and staying on routes that are mostly flat.
This brake was off a woman's Schwinn Breeze and looked to have almost no use prior to my getting the hub, it had no signs of wear on the internal parts. I ground a radius on the leading-edge of the brake shoes to help them work more smoothly against the hub, and to help them keep lubricant between them and the hub shell to maybe help cooling and reliability.
A coaster-brake bicycle is a beautiful simple machine, and for me that means using it for easy relaxed riding on routes that do not have long steep grades that could overheat them.