I've been over 49 on all of my recumbents, and I've hit 53 on two of them. Ironically, it's the two slowest ones. I'd have no problem with 55+, as long as the road was smooth and the sight lines were good. Heck, on one hill a few years back, I was coasting at 49 mph, and decided that wasn't good enough; so I put it in my 58/11 and cranked it up to 50.5 mph. The vista didn't look any different, but the number on the speedo was important!