My faithful Tacx rollers are finally in need of replacement. I estimate that I've put 2500 miles/year on them, each year since 1988. I got them for $60 at a shop that was going out of business, so I think I got my money's worth. The drums/bearings are fine, but the frame is too rusted to survive another rubber band change. My question is this: mine are the larger diameter (110 mm) drum version, now called "rollertrack" model. There is also a smaller drum version (80mm) called "ecotrack". Has anyone used both, and what are the benefits of one over the other? does the smaller give more resistence, as it turns more often? are the bigger ones smoother because they turn less often? I've also got the speedmatic resistence device on the old ones. thanks.