Hmmm... now here's a thread I can sink my teeth into
40-something SS rider ^
My SS is actually my newest bike- a 2009 Schwinn Cutter. I was admiring it at the bike shop for some time and my wife bought it for me for last Christmas.
I thought it was a big mistake at the time because I had developed knee problems. It ended up being part of my self-imposed physical therapy. I think the knee issue was caused by pedaling at a near-constant cadence on my hybrid and rarely changing seating position. The SS forced me to vary my cadence and get up out of the seat to climb hills. I think the variation helped my knee heal.