Mannheim is a city laid out like a chessboard, and that tells you most of what you need to know about it. The old centre was planned in the seventeenth and eighteenth centuries by the Electors Palatine, who built a vast baroque palace on the flat ground where the Neckar meets the Rhine and then arranged the streets in squares with letters and numbers instead of names. Locals call it the Quadratestadt. You will find that nobody needs a satnav to cross the middle of town, which is a rare luxury for a rider starting a long day.
The palace still dominates the centre and now houses the university, so on a weekday morning the forecourt is full of students on bicycles. It is one of the largest baroque palaces in Europe, and it is worth a slow roll past before you leave. The city has a quietly mechanical past, too. Karl Drais is said to have ridden his wooden running machine here in 1817, an ancestor of every two-wheeler you have ever owned, and Bertha Benz drove the first long journey by motor car out of this region in 1888, famously stopping at a pharmacy for fuel. Starting a motorcycle ride here feels oddly like paying respects.
The Rhine plain around Mannheim is as flat as a table, and the traffic can be heavy, with Ludwigshafen and its giant chemical works just across the river. Do not expect corners yet. The reward comes once you turn east and follow the Neckar into the hills of the Odenwald, where the Castle Road begins to earn its name, with Heidelberg only a short run away and ruins appearing above the river bends. Leave early on a weekend to get ahead of the commuter belt and the day trippers heading the same way.
Practical matters are easy. This is a city of more than three hundred thousand people, so fuel stations, cafes and bakeries are everywhere, and you can top up the tank and eat properly before the road narrows. Parking a bike near the palace or the water tower area is usually simple, though watch the signs in the central grid. If you want a coffee with some history, the baroque quarters around the palace are a good bet. The smell of the place on a warm morning is river water, hot asphalt and, depending on the wind, a faint chemical tang from the industry across the Rhine. Then you turn the key and leave all of that behind you.