Some serious standover -

XS XCL size - rider is 170cm, or approx. 5 feet 6 inches.  What do you think about the sizing?  I've asked the rider to measure the effective top tube length with this set up - let's see how the geometry works out!  For those interested in how to measure effective TT I found this diagram on the internet: www.surlybikes.com/blog/spew/spew_17_bike_fit

UPDATE: The effective top tube reported is 21".