I don't know exactly what I was running on the 1100R I rode. Looked
like 50 on the front, but may have been bigger. Probably 15 or 16 on
rear. Great for the brutal climb we were doing it was about right.
On my 800, I have 50/15 with the Rohloff. I get spun out on downhills,
but is great most of the time. Not sure what I'd want on an 1100.
Probably bigger. My understanding is that the Rohloff 15 is the
smallest you can do with the reversible sprockets. The 13 moves the
chain line very slightly and is not reversible. I didn't want to deal
with that. The 50 I have is the biggest stainless steel ring that
Surly makes that fits the 130 mm crank attachment points, and I like
having the all-stainless drivetrain.
I don't know about how fast it can go, with any gearing. As you get
faster, the resistance from the air becomes more and more significant.
Just because the gearing can do it, doesn't mean the particular bike/
rider combination can. Dan has gone to aerobars to lower resistance, I
narrowed my bars and just tuck in. You can really feel the difference
at those speeds of sitting up vs tucked down. So the speed question is
very open depending on what you are willing to do to get more aero.
For me it's all about speed up hills -- that's where I can make up
more time at say 30 up my big hill vs 20. At sea level it's harder
than at 13,000'.
I think the answer has to be getting the bike and riding it on your
routes and seeing what it does. Then change gearing based on what you
need.
--John