Speedo Myth

[donsobeck]

Took my new Saturn Vue on the interstate today to go to J.C.Whitney. Took along my stop watch set the cruise at 75mph and timed the mile markers. they came out to 48 seconds that is 3600/48=75mph. Checked the odometer for 30 miles and it showed 29.7 miles thats about 1% slow. I guess Saturn doesn't think about speedometers the same way BMW does. Is there really a federal law on speedometers?


DON

[TMH]

My understanding from Porsche-dom (which came before my BMWs) is that there is a German federal law on speedometers. In essence I was told that this German law was intolerant of speedometers which read too slow, and virtually mandated that speedometers in German vehicles were therefore all "optimistic" instead. Supposedly fines for speedometers reading low were potentially VERY high.

But I don't believe that there is a law in the US which even mandates speedometers in cars. If there was, and it specified accuracy, then all of our pleadings that "my speedometer must be off" might reduce the number of velocity awards that we get!

Tom

[k12steve]

My understanding from Porsche-dom (which came before my BMWs) is that there is a German federal law on speedometers. In essence I was told that this German law was intolerant of speedometers which read too slow, and virtually mandated that speedometers in German vehicles were therefore all "optimistic" instead. Supposedly fines for speedometers reading low were potentially VERY high.

But I don't believe that there is a law in the US which even mandates speedometers in cars. If there was, and it specified accuracy, then all of our pleadings that "my speedometer must be off" might reduce the number of velocity awards that we get!

Tom

Strange how that law didn't/doesn't affect my last or current R1200GS which was/is within 1 MPH of 2 different GPS's ;)

[DanDiver]

Doesn't seem to effect my wifes automobile BMW. It's speed is as accurate as my GPS!

[dshealey]

Doesn't seem to effect my wifes automobile BMW. It's speed is as accurate as my GPS!

My 525i reads about 5% fast, my 740iL is about one MPH high at 65. So, BMW is capable of doing better than on the bikes.

I think the '05 LTs are better than the previous years?? My '00 and '01 LTs were just about 10% high reading.

[Old_Wolf]

You guys actually pay attention to the speedometer??

[Steve_R]

Nope!!!

[mjordans2000]

'Strange how that law didn't/doesn't affect my last or current R1200GS which was/is within 1 MPH of 2 different GPS's'
__________________

I suspect that's just manufacturing tolerance at play. Two of my BMW M/C's are dead on accurate (or at least they agreed with 'Smokies' observations). The rest of them are off by about 10%.

[BecketMa]

They just got confused converting between knots per hour and miles per hour.

[bob_menton]

That's "knots" and "miles/hr", Bob - both units of velocity - that would make "knots/hr" a unit of acceleration, not speed. Nitpick of the day.:)

- Bob

[messenger13]

My cages are both spot on with the GPS, or there-abouts. BOTH of my current bikes (and my last V65) are all about the same margin off of the GPS. Indicated 60 mph = 56 actual. Indicated 100 mph = 93.5 actual.

I don't know what the indicated speed of my Ninja was at 160 mph actual. I didn't feel the need to look at the gauges at that particular moment in time. http://www.bigbikeworld.com/forum/smileys/smiley3.gif