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Speed Limiter...Why the Hell?

Help me understand the logic behind the speed limiter BMW, as well as other premium car manufactures, install on their vehicles.

It was a beautiful sunny day on Friday here in the St. Louis area. I decided to take the M for a stroll. I passed over the river into Illinois as started to drive south along the Mississippi. There are two areas where the road is flat, long, and very smooth south of the city. Beautiful day, no cars, and an M; this is a very dangerous combination. On this seductive stretch of road I hit that annoying limiter three times! Why, why does BMW torture us with this silly little device/

A friend chalked it up to litigation issues. I don’t buy it. Is BMW less “liable” if I wreck my vehicle at 140 mph versus 170 mph? What’s the logic?

Anyway, time for Powerchip…

Cheers,
JTG
 

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Re: Speed Limiter...Why the Hell?

The limit is in there due to a "Green party" pact that the major German car manufacturers (Audi, BMW, MB) signed to help limit the emissions produced I beleive. There is technically no law that says they must have it, but these 3 manufactuers all continue to stand by it. Maybe they get some sort of break on taxes or gov. grants for doing it?
 

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Re: Speed Limiter...Why the Hell?

I believe the speed limited so you don't overrun the speed rating of the tires. Z rated tires are "above 149". Since V is the highest true speed rated tire of 149, BMW can only be assured that Z rated tires meet this speed rating, although many exceed the speed rating Z rated tires are really either W (168MPH) or Y (186MPH). An explanation is:

"Any tire with a speed capability above 149 mph(240(kph) can, at the tire manufacturer's option, include a "ZR" in the size designation (P275/40ZR17). If a service description IS NOT included with the size description, the tire manufacturer must be consulted for the maximum speed capability(P275/40ZR17--speed capability is >149mph). If a service description IS included with the size description, the speed capability is limited by the speed symbol in the service description (P275/40ZR17 93W = maximum speed 168 mph(270kph).)"

http://www.tiresafety.com/size_class/size_nav2a.htm#srcharact
 

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Re: Speed Limiter...Why the Hell?

I belive Y is acually the highest speed rating of 186 mph.

Bmw set it to 155mph because that is as high as they test them to, and know at that speed its safe, above that they do not know. At least that is their stand. :)
 

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Re: Speed Limiter...Why the Hell?

Interesting.

Thanks jayson and Digi for the insights.

R/
War
 

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Re: Speed Limiter...Why the Hell?

Its the same concept as teh seatbelt, its mandatory to use them for your safety!
 

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Re: Speed Limiter...Why the Hell?

TCM is correct.

The 155mph speed limiter is due to an agreement between BMW, Audi and Mercedes. If they hadn't made an agreement, the German government would have been forced to make a law. This agreement is very similar to the one between the Japanese manufacturers not to build cars with in excess of 280hp.
 

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I dont think it has anything to do with tires. As said before its because of the Gentlemans Agreement made by the premium german car manufactures.
 

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if you think about it..i think its a bit of all of these..

in the old days (a couple of years ago)

155 seemed like a good speed to cap cars at (cept porsche..they unlimit their cars)

Now that cars can easily go past the 155 barrier..i think its a liability deal as well as a tire thing perhaps
 

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Yes, it is politics. BMW M manager said in order to have unlimited Autobahns in Germany this is the concession they have to do.

Although the deliberitely make it very easy to renove the limiter.
 

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Gustav said:
Yes, it is politics. BMW M manager said in order to have unlimited Autobahns in Germany this is the concession they have to do.

Although the deliberitely make it very easy to renove the limiter.
Really? Pray Tell
WillM5AD
 

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Re: Speed Limiter...Why the Hell?

kees said:
This agreement is very similar to the one between the Japanese manufacturers not to build cars with in excess of 280hp.
Does it exist an agreement between Japanese manufacturers? I thought it was only due to the extreme HP tax which starts at 281hp.
 

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Re: Speed Limiter...Why the Hell?

kees said:
TCM is correct.

The 155mph speed limiter is due to an agreement between BMW, Audi and Mercedes. If they hadn't made an agreement, the German government would have been forced to make a law. This agreement is very similar to the one between the Japanese manufacturers not to build cars with in excess of 280hp.

you know there has and is quite a few jap cars that have 300 plus hp.
 

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Re: Speed Limiter...Why the Hell?

Jayson said:
you know there has and is quite a few jap cars that have 300 plus hp.
Not on those produced for the Japanese market. Many of them have only 280hp on paper...but when you put them on a bench they surprisingly have more.
 

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Re: Speed Limiter...Why the Hell?

kees said:
Not on those produced for the Japanese market. Many of them have only 280hp on paper...but when you put them on a bench they surprisingly have more.
300zx, newer 350z limited coming are two that come to mind that have/had over 300 hp. Both advertised and truely.
 

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Re: Speed Limiter...Why the Hell?

Opposite_Lock said:
It's not for all the German premium marques. Porsche is conspicuously absent.
I thought Porsche was 'abscent' because they are a 'small volume' manufacturer.

How about VW, does anyone know if they adhere to the 155 limit as well? I know most of their cars won't make it power-wise, but the Phaeton surely has sufficient horses to exceed 155 MPH. hmmm hmmm And they sell a lot of cars in Europe.

CP
 

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Mardeth said:
I dont think it has anything to do with tires. As said before its because of the Gentlemans Agreement made by the premium german car manufactures.
It was an agreement with the German govt because the govt was considering placing speed limits on the autobhans. Only Porsche aren't included in this deal.
It's not because of tyres or anything else.
 

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Re: Speed Limiter...Why the Hell?

Jayson said:
300zx, newer 350z limited coming are two that come to mind that have/had over 300 hp. Both advertised and truely.
The hp agreement was for Japanese-market cars.
 
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