Why do many high performance cars like the BMW M6 have top speed limiters??

Question

Surely limiting a £50-60K BMW is stupid when a 19grand Vauxhall Astra can reach almost the same top speed....?

Answer 1

As already said, it is because of a gentlemans agreement between Audi, BMW and Mercedes.

The coming about of the agreement is nothing to do with tyre ratings though. It was because the German government were threatening to put speed limits on the unrestricted sections of the Autobahn. This was because cars were getting faster and faster.

So the big 3 in Germany made a deal saying that they'd restrict their cars if the government backed down. Deal done.

Since then, other manufacturers have followed suit but given their reason as safety. Some manufacturers didn't bother (most notably Porsche) whereas others put a different limit on their cars.

It's either Subaru or Mitsibushi that set a 160mph limit, so that their cars were faster than M5s etc.

The agreement has recently been dropped although I suspect manufacturers will maintain it on safety grounds. Audi are releasing the R8 with no limiter on it as a direct challenge against the Porsche 911.

Mercedes tuning arm AMG will raise the limit to approx 185mph if you ask them, but will not go higher because they will not supply tyres rated high enough.

Other tuners will remove the limiter completely allowing a BMW M5/M6 for example to hit over 200mph. Tyres are available that can handle that sort of speed, but they are not "approved" by the car manufacturer.

Your £19K Astra could indeed hit 155mph, but it certainly wouldn't do it as comfortably or as fast as a £60K BMW/Audi/Merc.

Answer 2

Where would you actually use this said top speed? On a public road?

I think that these cars should have the ability to remove the top speed on a track only, and then have it put back on. Perhaps via OnStar or something like that, so that the fuzz can slow you down if you're trying to get away as well. That would be nice and save a lot of lives by preventing a high-speed chase before it happens.

Answer 3

i can't say 100% about the M6 but in many cases it's tire speed rating from factory (certain mustang models ,buick Gand National and Gmc SYCLONE all come to mind all had 'H' rated 130 mph tires with 'Z' capable 150 + mph engines) other reasons include fear of lawsuits and in europe as is the case with at least 2 bikes ,deals with the government have limited bike speed to 320kph (189 mph)see suzi 'busa and kawi zx14.also look at more expensive bmw's lots of companies (like chevy when it comes to corvette) do not want the cheaper cars outrunning the more expensive stuff. But there is a reason and you can bet it is money motivated,just be like SHERLOCK and sniff it out

Answer 4

It's an agreed speed decided among manufacturers, BMW, Mercedes & Audi especially, to cope with generally available tyre technology.

Answer 5

Its a "gentleman's agreement" amongst German manufacturers to a maximum of 155mph because of the unlimited stretches of German autobahn. Here in the UK both vehicles should be driven maximum of 70mph in any case!

Answer 6

its a gentlemans agreement to limit production cars to 155mph. its so plod can have a chance of catching people... and at 166 plus gatso cant see you!