I first ordered these shorts in a Small. I am on the borderline of S or M for most cycle gear. I could barely get into Small so sent back and re-purchased as a Medium. The returns policy is effortless and works well. The Medium arrived and was still way too tight. I shall most probably now try the Large as they seem a well-made pair of cycle shorts & I do need to replace some worn out ones. But the current Endura sizing does seem to have moved into a parallel universe where customers have deemed to have shrunk, compared to the sizing of a few years back.

At 6'3" and 11.5 stone I selected a large fit I bought a large size and they are very snug on the leg and waist. A first ride of only 35 miles was starting to get uncomfortable in the groin as the fabric was not adapting to my movement. Perhaps this will improve with time. Good seating comfort and so long days in the saddle should not be a problem. Good length in the leg, longer than the average short I would say

Ordered a large, fits spot on, efficient service. 

I tried on a pair of these FS260 Pro shorts whilst touring in the UK in (May) in 3/4 lycra bottoms (i.e. below the knee style) and getting too hot. I'm not exactly a big guy, a medium in most non-cycle wear, 33" waist, 37" hips, 20.5" around the largest thigh section. The store only had medium in and they were way too tight. I ordered a pair of Large from an on-line cycle store that should be too big according to the Endura guide and these fit me fine. Only time and miles will determine the true quality and pad effectiveness.