I'm 5'8" and my Brompton is a 2013 S6L-X.
I've done rides up to 60 miles on my B'ton.
Will be a volunteer marshal for the NYC Century
this Sunday, will be trying to complete the
100 mile route.
40 mile event:
https://www.youtube.com/watch?v=lmFU...6zPoymgKaIoDLA
Another 40 mile event:
https://www.youtube.com/watch?v=fgIz...aIoDLA&index=6