I have been wondering why people have been zooming by me on the interstate over the 2 months I have owned this bike. Today I took a handheld GPS and Im about 9 mph off. When Im showing 72 miles per hour Im actually9 mph slower. Its a smaller difference at lower speeds I think. Will double check tomorrow.

Is there any way to correct this problem? Its difficult to calculate the difference in my head at all the differentspeed limits i ride in.

 

I'm not sure how to change it. I think I'm about 3-5mph slower than what's on the speedo.
I'm just gonna flag down a cop and makehim hit me with the radar or something. That way i'll know for sure. My gps only does trip averages. [:@]

 

Find someone with a Blackberry cell phone and take them for a spin. They have a built in GPS.

 

yeah, that should work. I think I may be able to hit the reset on mine, at speed, then hold speed and get an accurate average.

 

Are you running stock tire sizes and gearing?

 

Just go faster, I allow 10% for the speedo and 10% for the cops, so Iread 120 in a 100k zone (when I'm good)

 

Only way I know to correct is to go 1 tooth UP on the front sprocket, which will reduce error by about 7%.........

 

Mine's out aswell i know i can go down the motorway doing 79mph knowing im ding 70mph, my sat-nav and gps on my phone helped me sort the speeds out, and i know the faster i go the error stays the same, Theoreticly of course....

 

I am one tooth down on the front sprocket according to the previous owner. Dave, I believe your theory is correct. Atspeeds of around 40mph, Im 4mph off. At around 70, Im 9 mph off. Maybe I can place a sticker on the speedo marking my spots. Law enforcement around here is not going to go for the old excuse "my speedometer is off"when Im on a hoss llike the hurricane.Does this meanthose wonderful gas mileage calculations I have been getting are incorrect?

 

Sounds like you found the culprit. A smaller sproket up front. Switch back to stock if you want a more accurate speedo or figure out how much error to compensate for if you like the gearing you have now. Sounds like you awesome gas mileage was definitely aided by your speedo error.