A touring bike should always have a pretty long chainstay for heel clearance on the panniers. I wonder why the different chainstay lengths for the same sized S and L frames? A size S frame is unlikely to have smaller panniers.
I agree with you, mickeg. If I need a certain length of chainstay on a flat handlebar bike to prevent heel strike whilst keeping the centre of gravity of the pannier from being too far behind the rear wheel axle, I will also need that same chainstay length on a drop handlebar bike. (Edited. Of course, mickeg, you're correct. The COG of the panniers is behind the rear axle not in front.)
You need to look at all the geometry together and come to your own conclusions, or trust that those designing know what they're doing.
Looking at chainstay length, without considering seat tube angle is a mistake, the bottom bracket is in a different place relative to the saddle.
PH, I do agree with you, especially on a racer or audax bike. Not so much on a tourer built for carrying extreme weighs. When adding extreme loads it is more important to be able to place them within the axle centres. Also, looking at chainstay length and seat tube angle, the Nomad Mk2 620L has 72.5° seat tube angle and 479mm chainstays and the Nomad Mk3 61S also has 72.5° seat tube angle but 459mm chainstays.
If I at 6'5" with size 13-14 UK feet were to buy a drop bar Nomad, I would want the geometry of the Mk2 620M rather than the Mk3 61S for heel clearance, I would also prefer it's seat tube length, standover height & slope, seat tube angle. I would probably also prefer it's 595mm TT.
The rider of size S frame will likely have smaller feet and maybe shorter cranks too.
brummie, I disagree. I think that the rider of the S frame is more likely to have the same size feet but be using drop bars rather than flat bars, especially now with the longer seat tubes and taller standover heights. At least, as likely, in my opinion.
