Nordrhein-Westfalen (or in English North Rhine-Westphalia) is the most populous and economically the largest of the German states. It is more a destination for business rather than holiday but biking along the Rhine is one of the highlights for cyclists. It is part of the Rhein Radweg, the 1230 kilometer cycling route along the Rhine, starting in Swiss Alps and ending in Rotterdam, the Netherlands. In most places, the route is sign-posted and maps show you points of interest in the neighborhood.
The main cities along the Rhine are, from south to north, Bonn, Cologne, Düsseldorf and Duisburg. Between the cities you find some farmland and smaller towns. It is not the most scenic cycle route in Germany but it is a nice change from the cities. And you don’t need to climb any mountains, it is flat along the river.
Bonn was the capital of the former West Germany. It has survived the loss of status fairly well and is a nice place to visit. It is less busy than the larger cities of Cologne, Düsseldorf and Duisburg. In summer the route along the Rhine down to Koblenz is popular. It is possible to continue all the way down to Mainz as well, passing the infamous Lorelei Rock along the way. It is the narrowest part of the Rhine in Germany. Strong current and rocks under the surface have caused many boat accidents over the years.
The popular route between Cologne and Mainz is generally broken into four days of cycling:
Day 1: Cologne – Bonn (42 Km)
Day 2: Bonn – Koblenz (59 Km)
Day 3: Koblenz – Trechtingshausen (58 Km)
Day 4: Trechtingshausen – Mainz (35 Km)
It is also possible to stop in Koblenz and taking the train back. The only climb is at Andernach on the second day.
The stretch between Bonn and Cologne is easy, and if you get tired the train is not far away. Cologne is a large city and you can not always cycle directly along the river but signs will tell you what way to go. So even without map or GPS navigator you are unlikely to get lost.
Once you have managed to get out of Cologne, you have a fair bit of country side, and the huge Bayer industrial plant, before getting to Düsseldorf. Note that sometimes you will be a fair bit from the railway. The route along the river is nice, often on bike paths so no need to worry about cars. In Düsseldorf, you can make a stop at the old tower on the east side of the river and get something to drink and eat.
Also the part between Düsseldorf and Duisburg is easy. In Duisburg, you can have a look around the old harbor. It is not as busy as it used to be but it is still supposed to be the largest inland port in the world. Duisburg is also the western entry to the Ruhr-Gebiet, the old industrial powerhouse. And if you continue along the Rhine, after a while you will enter Holland and later on Rotterdam.
Remember that while it easy to cross the river in the cities, outside the cities it may be a long way until the next bridge or ferry, so plan ahead. Most German cities are cycle-friendly, with a fair number of bike paths so you don’t need to mix with the cars.