I did a little research on frame geometry, and the numbers show that two of my bikes are pretty darn similar. My 1987 Trek 520 and my 2010 Surly Cross-Check stack up like this:
The cross-check has shorter chainstays, and a longer top tube. The Cross-check also takes monster truck tires, while the Trek tops out around 38mm. I’m thinking a drivetrain switcheroo might be in order. The CC could easily be my primary bike, but it isn’t because the Sturmey Archer gearing is a little too high for most of the hills around here.
With a wide gear range, and suitable tires, the CC might be the better bike for 99% of all the riding I do, and the Karate Monkey would probably be better for the other 1%.
Not sure what I’d do with my beloved Trek, then.