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petez
Guest
Is it possible to calibrate the speedometer on an oilhead R bike? I have seen many methods for doing this on K bikes.
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jdiaz said:It depends. In the engineering world, we call that "tolerance," not error. Kinda like those exit polls that have a range of confidence.
Tolerance is in both directions. BMW speedos are always off in the same direction by about the same percentage. That's German engineering. <G>
paper
In need of a nap.
I tossed my GPS in my tankbag to do a speedo test on my R1100R and was amazed with how accurate it was.
It was never off more than 2 mph at speeds between 20-100 mph..
It was worst at 30 where my speedo showed 30 and the GPS was at 28. At 100 it was only 1.3 mph off..
This was with my Magellan SportTrak Pro with WAAS...
It was never off more than 2 mph at speeds between 20-100 mph..
It was worst at 30 where my speedo showed 30 and the GPS was at 28. At 100 it was only 1.3 mph off..
This was with my Magellan SportTrak Pro with WAAS...
cat0020
New member
From my experience, GPS unit can vary on their accuracy.
depending on the refresh rate of the GPS signals, it may take up to 3 seconds before the GPS calculates your speed, so the speed that's displaying on your GPS unit could very well be your speed 3 seconds ago, rather than instant speed.
My R1150RS' speedometer is usually 5-7 mph faster than my Garmin Streetpilot displays on the screen. as the speed gets up to the triple digit, the difference between the two becomes smaller.
depending on the refresh rate of the GPS signals, it may take up to 3 seconds before the GPS calculates your speed, so the speed that's displaying on your GPS unit could very well be your speed 3 seconds ago, rather than instant speed.
My R1150RS' speedometer is usually 5-7 mph faster than my Garmin Streetpilot displays on the screen. as the speed gets up to the triple digit, the difference between the two becomes smaller.
Paper said:
paper
In need of a nap.
You could be very right about the refresh rate, but this was done on a straight, flat road with my ThrottleMeister and looking back and forth between the speedo and the GPS.
All speeds were actually held for about 15 seconds as I glanced back and forth between the two to make sure what I was seeing would be correct.. OK... At 100 I might have been in a little more of a hurry than 15 seconds..
I didn't do this to post it here for your reading or questioning. I did it 2 months ago to find out where my speedo stood in the real world of speed... Or even more so, in the real world of tickets.. Also, I was getting 8 to 10 satellite's information during the entire test.
I did the exact same thing with my Toyota T100 and my VW GTI..
The most amazing part of this was that my BMW has the most accurate speedo.. OK.. Both the car and truck aren't running stock tire sizes, so I'm sure that is a huge factor on them...
All speeds were actually held for about 15 seconds as I glanced back and forth between the two to make sure what I was seeing would be correct.. OK... At 100 I might have been in a little more of a hurry than 15 seconds..
I didn't do this to post it here for your reading or questioning. I did it 2 months ago to find out where my speedo stood in the real world of speed... Or even more so, in the real world of tickets.. Also, I was getting 8 to 10 satellite's information during the entire test.
I did the exact same thing with my Toyota T100 and my VW GTI..
The most amazing part of this was that my BMW has the most accurate speedo.. OK.. Both the car and truck aren't running stock tire sizes, so I'm sure that is a huge factor on them...
paper
In need of a nap.
Cat0020,
Ever been to IL?? Rural IL??
Nothing but one mile squares.. Flat one mile squares. At that time the fields were only tilled with nothing even planted yet..
I appreciate your concern for my safety and your questioning of my experiment, but unless you were there, I don't understand why you don't believe me.. I have absolutely no reason to lie. I only told you my findings between my GPS and my speedometer.
Send my your Garmin and I'll do it again, or even better come on over to IL and ride next to me..
Ever been to IL?? Rural IL??
Nothing but one mile squares.. Flat one mile squares. At that time the fields were only tilled with nothing even planted yet..
I appreciate your concern for my safety and your questioning of my experiment, but unless you were there, I don't understand why you don't believe me.. I have absolutely no reason to lie. I only told you my findings between my GPS and my speedometer.
Send my your Garmin and I'll do it again, or even better come on over to IL and ride next to me..
paper
In need of a nap.
Testing the speedo is the ONLY thing that flat straight roads are good for.. They suck for everything else.. BAD!!! Unless you like flat spots across your rear tire.
Lucky for me, Southwestern Wisconsin is a fantastic area of curvy, hilly roads with little traffic. And it's only 1 hour away from the good stuff. I go over there just to put wear on the sides of my tires.
Lucky for me, Southwestern Wisconsin is a fantastic area of curvy, hilly roads with little traffic. And it's only 1 hour away from the good stuff. I go over there just to put wear on the sides of my tires.
Speedo errors
My '95 R11GSA was 5 mph fast according to police radar and Garmin III GPS.
My '97 R11RA was 5 mph fast according to same.
My '02 R1150GSA was 7 mph fast according to Garmin III and Garmin 176 and radar readings. On the '02 GS I put a speedo hub with the 3.0 gear ratio on the front from an R11RA and it brought the reading to only 2 mph fast.
Andy
Jennings, La.
My '95 R11GSA was 5 mph fast according to police radar and Garmin III GPS.
My '97 R11RA was 5 mph fast according to same.
My '02 R1150GSA was 7 mph fast according to Garmin III and Garmin 176 and radar readings. On the '02 GS I put a speedo hub with the 3.0 gear ratio on the front from an R11RA and it brought the reading to only 2 mph fast.
Andy
Jennings, La.
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petez
Guest
Judging by the responses, no one knows whether it is possible to adjust the speedo on an R bike. A friend has one, so I will take it apart and see whether it is similar to the K-bike's instrument.
I was able to adjust my K1100 to be absolutely correct at 60 MPH by tweaking an internal potentiometer.
I was able to adjust my K1100 to be absolutely correct at 60 MPH by tweaking an internal potentiometer.
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petez
Guest
I can check easily enough. If there is an electrical speedo sender mounted on the top of the final drive, then the speedo is electric, and presumably can be adjusted the same way the K bikes can.
