Why Do German Sportscars Have a 155 MPH Top Speed Limit?

When you think of German sports cars of the last thirty or so years, images of precision, performance, and engineering at its finest come to mind. All of these images point to one thing: The top speeds of this fine machinery should be unbearable to the human body and almost unlimited. But there is a plot twist to that. Almost all of these high-performance cars have a 155 mph top speed limit, with a only few exceptions.

That’s right. While American muscle is all about unrestricted power, many of the European competition have long been capped at 155 mph. And there is a story behind it.

A Gentlemen's Agreement

German auto manufacturers—namely the usual suspects, BMW, Mercedes-Benz, Audi, VW, and the like—came to an informal “gentlemen’s agreement” right after the 1970’s oil crisis. The agreement's goal was to limit the sports cars’ top speed to around 250 kph, roughly equivalent to 155 mph. For the die-hard petrolhead, this might sound like a weak link in the high-performance realm, but when you consider different aspects, the 155 mph top speed limit starts to make sense.

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High-speed driving isn’t just about raw horsepower and aerodynamics. It requires capable tires, advanced suspension, and a braking system that can take the stress to handle extreme speeds. Back in the day, tire technology was not as advanced as it is today, and tire failure at high speeds was quite a real concern. By introducing the 155 mph top speed limit, the manufacturers ensured the vehicles stayed within the safety net. The limitation was as much about protecting the drivers and keeping insurance in check as it was about preserving these fine machines’ integrity.

Politics, Safety, and Engineering Comes Together

We, American car guys, might be giggling about “limiting” an all-out performance car. After all, American culture is all about being big and brash, and when it comes to performance, power and speed are the most important. But the story behind the 155 mph top speed limit is a great story of how politics, safety, and engineering come together. Instead of letting political pressures dictate strictly, German manufacturers opted to regulate their performance cars all by themselves. The agreement was a clever solution that gave them a responsible image while still producing cars that deliver blistering performance.

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And let’s be honest here; 155 miles an hour is NOT slow. On top of that, if you’re driving one of these machines, you can still smash the 155 mph top speed limit. Many of those cars, the RS Audis, BMW’s M cars, or AMG-tuned Mercedes-Benzes, allow the limit to be removed with a simple ECU tune or a remap. After all, the 155 mph top speed limit is more like a guideline than an absolute law.

The top speed restriction also allowed the manufacturers to avoid an arms race. Without a top speed limit for German sports sedans and sportscars, every manufacturer would try to outdo the other by pushing the boundaries for insanely high numbers. That would bring stricter and tighter government intervention. Or worse, a public backlash over safety concerns.

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The 155 mph top speed limit, or the “gentlemen’s agreement,” points to a fascinating period in automotive history that shows even the biggest manufacturers sometimes choose to restrain themselves instead of offering raw and uncontrolled power.