I'm not looking to start an arguement or anything BUT ...

With regards to roller wheels with roller bearings versus bushings:

Bronze has been around since, well, "the bronze age" Its a known fact that it is probably the best bushing material on the planet. BUT it took years before any company decided to use it in a roller lifter. Why is that? Is it feasible that no engineer ever considered it until some time within the last 20 years?!?! I can't imagine there have been any advancements in the metallurgy of bronze that would have made it any better. So what changed, I'd really like to know

With that said, I've always pondered the beating those rollers must take from the amount of "lash". Seems to me you'd want something really tough in there - like steel bearings as opposed to softer bronze. And then there's the lubricating issue. The rollers have space between them to retain oil. A bronze bushing does not. And in case you're considering it, this is NOT a place you'd want to use sintered bronze.

So ponder these thoughts when you have nothing better to do. I'd be interested in hearing valid comments pertaining to the how and why.