After having my knee scoped in Oct 2007, I was able to ride about 3 miles at a time by Jan 2008. In July 2009 I completed RAIN (160 miles in a single day) in under 10 hours. For me, the key was not to push too hard going up hills or sprint. Any serious pressure on my knee leaves me sore for days. Got to be happy with 160 miles in 10 hours though