Making the sixty-mile trip to Pforzheim, though, was not as simple as pointing the Motorwagen in the right direction and pressing the gas. The roads along the way had not been designed for automobiles. They were muddy and rutted, a difficult environment for a vehicle that had never before been taken off the shop yard. Hills proved challenging to the 2.5-horsepower engine as well. A few times Richard and Eugen had to get out and push the Motorwagen up particularly steep inclines, and at one point they even had to conscript some farm boys that they came across in order to summit a hill.
While the terrain was tough, the biggest challenge was just keeping the vehicle running. A primary concern was finding fuel. They had departed from Mannheim with a little over a gallon of fuel in the carburetor, but they would have to find more along the way. Fortunately, the Motorwagen could run on ligroin, a solvent commonly sold in apothecary shops.
Bertha planned her route accordingly, passing through small towns along the way where she might acquire the stuff. At her first stop in Wiesloch, Bertha bought the pharmacy’s entire stock of ligroin, despite the chemist’s protestations that she would only need a small amount to clean her soiled and stained dress.
A second concern, after fuel, was water. The Motorwagen’s engine was cooled by means of an open thermosiphon system, dissipating heat by evaporating water. As a consequence, the auto drank water even faster than fuel. Bertha and the boys stocked up on water whenever they stopped, but also occasionally had to search out streams and brooks in the countryside to prevent the Motorwagen from overheating.
The final obstacle on the trip was maintaining the delicate mechanical components of a vehicle that had never before been driven more than a few hundred yards. Bertha had an intimate understanding of the workings of the Motorwagen, and proved to be quite resourceful in solving mechanical problems on the fly. When a fuel line became clogged, Bertha used her hat pin to clear the obstruction. Further along in the trip, the ignition failed when exposed wires short-circuited the system. She remedied this by wrapping her garters around the offending wires, thereby insulating them.
In two instances Bertha had to seek out the help of local craftsmen to get the Motorwagen running again. When she discovered that a chain had broken, she enlisted a blacksmith from a nearby town to fix it. Near the end of her trip, she determined that the brakes, which were made of wood, were beginning to fail from continued use. She sought out a shoemaker to nail strips of leather to the brakes, thus inventing brake pads.
Bertha and her sons arrived in Pforzheim just as the sun was setting, and Bertha sent Karl a telegram letting him know that they had made it. He may have been put off by the impromptu trip, but he would incorporate the lessons that Bertha had learned into his design, adding the brake pads and new lower gear for climbing hills. More importantly, the sight of a woman and her two children passing through German villages in an automobile sparked the attention of the press and the story spread. Orders for the Motorwagen started pouring in, and soon Benz & Cie. would be putting six hundred automobiles on the road every year.