Swapped some alloy rims someone gave me onto the LeToaster this past week as was interested in if it would make the bike feel any different. This bike with steel rims was very stable when riding hands-off, especially at higher speeds where the heavy steel rims could create more gyro force so I was wondering if the bike would be less stable. I weighed the bare rims on a gram scale and was surprised at how little difference there was in weight. Sure the alloy rims are lighter, but not such a savings in weight that they are going to turn the bike into a feather. It saved less than a half-pound going from steel to alloy rims. the front hub on the new front wheel is small-flange, so that may have saved a small amount of weight too, but it is not noticeable in lifting this bike up after the parts swap. The rear coaster brake is very heavy, so the alloy rim helps make up for that.

Surprisingly, the average steel rim is not any stronger than an alloy rim. I have had problems with steel rims when hitting harsh roads and other obstacles where the rim will become dented our out of shape, the alloy rims seem to have more spring in them so may be harder to repair if damaged, but a bit less likely to be damaged under the same road conditions.

I did not notice the bike was any more difficult to ride hands-off. A lot of stability is designed into the later 70s Schwinn frames and forks. I have ridden some 27" road bikes that are much harder to keep straight with the hands off the bars, so the loss of gyro force with the lighter rims did not affect this chassis.

I swapped the rims out of boredom and curiosity, but for most I would not recommend it unless your old steel rims were damaged or you ended up with the alloy rims for free like I did, and you have fun taking wheels apart and lacing them back up as I do.