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Discussion Starter #1
What is more accurate? when my speedometer says 77mph and gps reads 70mph. i then put my gps in my car . when my gps reads 70mph and my car reads 66 mph . why the big difference?
 

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The GPS is much more accurate. Most speedos run a little high. BMW motorcycles tend to run a little higher than most...
 

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Miles of Smiles
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Straight and Level

The GPS every time with this proviso. Level road, straight, no sky obstructions. To be honest, the satellite sampling rate is so frequent, it's as good as it gets.
 

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64

When does 100 = 90? Only on an LT. Possibly you are new to the LT. The speedometer is notoriously inaccurate, but at least consistent. Unless you have done "the speedo modification", you need to subtract approximately 10% from your indicated speedo reading to get the correct MPH. God love those quirky little german engineers, they just can't seem to make an accurate speedometer for the LT. Just one more thing that bonds us together as a community.

Steve
2004 LT
 

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I've owned 8 other street bikes that were not a BMW, and ALL of them had just as inaccurate of a speedometer as my LT (before I did the 'speedo correction' mod to it). I just think that most riders through the years were not aware of how badly their bike's speedos were off. But now that we have a GPS mounted to the bike, the error is revealed like never before.
 

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Discussion Starter #6
xenia said:
64

When does 100 = 90? Only on an LT. Possibly you are new to the LT. The speedometer is notoriously inaccurate, but at least consistent. Unless you have done "the speedo modification", you need to subtract approximately 10% from your indicated speedo reading to get the correct MPH. God love those quirky little german engineers, they just can't seem to make an accurate speedometer for the LT. Just one more thing that bonds us together as a community.

Steve
2004 LT
i am new to the community,bought a 2002 LT a couple of months back and absolutly love it. don't think it gets any better than this bike. smooth as a caddy and corners like my supra.
 

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dodk64 said:
i am new to the community,bought a 2002 LT a couple of months back and absolutly love it. don't think it gets any better than this bike. smooth as a caddy and corners like my supra.
Smooth as a caddy?! Now I KNOW you meant to say, "smooth as a 7 series" . . . didn't you?! :rotf:
 

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messenger13 said:
Smooth as a caddy?! Now I KNOW you meant to say, "smooth as a 7 series" . . . didn't you?! :rotf:
Exactly! When my co-workers say my bike is the Cadillac of motorcycles, I always correct them with "No, it's the BMW of motorcycles"
 

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Had a guy in the gas station say "BMW, now that's a cadallac."................
I said "better than that, it's a BMW."
 

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... continuing the hijack...

STARFIGHTER said:
Had a guy in the gas station say "BMW, now that's a cadallac."................
I said "better than that, it's a BMW."
My favorite: "BMW? BMW? When did BMW start making motorcycles?
 

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Discussion Starter #11
messenger13 said:
Smooth as a caddy?! Now I KNOW you meant to say, "smooth as a 7 series" . . . didn't you?! :rotf:
can't afford either ,so i guess smooth as a 7 series it is.
 

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Getting back to the original question - the GPS is almost 100% accurate. Almost because there is a deliberate built in constantly moving position error of about 20 meters as I understand it. So in absolute terms the calculated speed shown would be out, but probably only by a decimal point.

Traditional speedometers are only accurate at one speed. Above that they normally under-read and below it over-read. And that's when the tyres are brand new. any other time and the ratio is out.

In speed limits I always set the cruise by reference to the GPS.

Kevin.
 

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I'm former LEO and have checked my GPS against the RADAR unit I use( No Flaming Please). It was pretty much dead on with the radar.
 

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I never look at my speedo anymore - my GPS is the unit that gives me the best chance of not falling prey to a performance award.

Denny
 

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And all this time I thought the LEO's were just being nice to me. ;)
On every bike I've owned, the speedo has been off by as much as 10%. the faster I go, the worse it gets.
Happy to use the GPS now, but I also know I no longer have an excuse...
 

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I agree GPS always although the reaction time to changes to speed is kinda slow. Checked my 2009 LT last weekend and speedo was off (fast) by about 4 mph at any where from 50 to 70 mph. Also checked the odometer and was only off by 1/10th of a mile after 40 miles traveled. Can't get much better. Don't assume that speedo error also means odometer error in all cases. Heck my 2006 BMW M Roadster is almost 4 mph fast at 70 mph while my GMC SUV is perfect. Must be a German thing I guess. Of the dozen or so bikes I've owned over the years my 2002 Road King is the only one that had an accurate speedo. Probably less than 1 mph error at 70 mph. Go figure, the least technically sophisticated motorcycle on the planet!
 

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After I mounted my GPS, my riding buddies all asked what was my hurry. “Why are we running 80 mph?” They all doubted me when I told them we were only running 73.6 mph. It took a while but they all run 80 on their speedos now.
 

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Yep all those speedo's are inaccurate. I'm off by about 4 mph. It's complicated to make a speedo that is accurate all the time, without constant calibaration.
 

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Caveno said:
Yep all those speedo's are inaccurate. I'm off by about 4 mph. It's complicated to make a speedo that is accurate all the time, without constant calibaration.

Maybe wrong here, but I was under the impression that the over read was a requirement. At least it is a requirement not to under read, so a small margin is built in?

Almost every speedometer I have checked is 10% over.
 

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rab1967 said:
I'm former LEO and have checked my GPS against the RADAR unit I use( No Flaming Please). It was pretty much dead on with the radar.
Ditto on that.

Just wondering. If the speedo are off, show slower speed, then how come some of you still get nailed for speeding?????????hmmmmmmmmmm:)
 
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