Re road surfaces. I found the following accurate in my limited northeastern Germany experience:
https://www.adventurecycling.org/adventure-cyclist/online-features/tour-it-yourself-cycling-in-europe/
One special mechanical note about Germany is that, while bike paths
are everywhere, the material and quality of the paths is variable.
Gravel and pavement are marked identically on the ADFC maps, and curbs
and tree-root bumps are common and can cause pinch-flats. The Germans
adapt to this with fatter tires (35mm or more), which might be wise
for a lengthy tour there.
http://www.bicyclegermany.com/path_conditions.html
Pavement: I want to stress that most of the time we ride on some type
of pavement. If we are not on an asphalted surface, the pavement could
consist of concrete or any of several types of brick pavers.
Nevertheless, for the last several years, I have snapped a photo every
time we encounter an unusual path condition. The photo on the right is
a concrete path and on the left is a photo of an asphalt path; both
mean perfectly smooth riding.
Gravel path with puddles. Gravel: The second most common path
condition is gravel. The gravel is typically tightly packed and can be
as smooth as concrete or asphalt but it is subject to mud puddles in
wet weather (left). If I were to guess, after over 20,000 kilometers
of riding bicycle paths in Germany, I would say that 70% of the time,
the paths are paved with either asphalt, concrete, or some other type
of relatively smooth paving like brick pavers. The remaining 30% is
mostly tightly packed gravel. But what is not gravel is all the
remaining path conditions discussed on this page. These non standard
portions turn out to be the most memorable portions, unfortunately.
Dirt: Dirt Paths occur occasionally. The photo of the single track on
the right is one such path but as most dirt bicycle paths, it is well
packed and quite safe in all but the wettest conditions. There are
several short stretches of dirt paths we have experienced. single
track foot path but part of bike path tooSome are double track paths
like the one on the left. Others are a bit dicey to ride because they
are narrow foot paths but nevertheless signed as part of the official
bicycle path. An example is one we found in a bird reserve (also on
the left).
Cobblestone bike path, Cobble roads are made of rocks, or in this case
granite blocks chiseled into uniform sizes and set in a sand base by
workers on hands and knees.
Short steep paver and stone way
Plattenweg (a path made from Platten) is another instance of using
less than ideal material for a bicycle path. A "Platten" is a
concrete plate with two or four indentations for handles. They vary in
size but typically are about 3 feet wide and 6 feet long. [For a
paved path these are brutal.
Sand, especially deep sand: By far the worst path condition is deep
sand like the photo on the right. The German state of Brandenburg,
which surrounds Berlin, is infamous for sandy soil but that is not the
only place in Germany that has sandy soils. The northern lowlands
around Mecklenburg-Vorpommerm has a lot of sandy deposits but is not
sandy all over.
