| Author | Message | ||
     Zuhl |
I made my first long(ish) trip on my Uly this weekend (about 450 mi round trip) and had my garmin GPS mounted to map my progress. I switched to the speed display and noticed that my indicated speed on the bike was about 4% higher than my actual speed per the GPS. Does anyone know if this is common and how to adjust/correct this? The guy I bought it from had put an aftermarket ECM in it, but I dont know if this could cause the change or not. That is just for fuel mapping, right? I just about need to replace my rear tire, but I don't think that small of a change in diameter from a new tire would cause a 4% error. On another note, even accounting for the error I got almost 53 mpg on tank and about 50mpg on average. Thanks for the help! | ||
| New12r |
No way to change it... All speedometers are optimistic from the factory, thank your lawmakers. | ||
| Zuhl |
Really? Wierd. On cars you can use a scanguage to change it given different axle ratio or wheel size combos. Guess on a bike you are SOL. I wonder if there is a certain near tire size that might correct the error? | ||
| Dynasport |
I wouldn't change tire size just to get a more accurate speedo reading. Just go with it. Speedo says 80 MPH, you know it is more like 75. No big deal. | ||
| Terrible1one3 |
legally speedo's have to be within 5% of the actual speed. Harleys have been way further off than that in the past and the fact that buells and harleys are within legal limits now is a huge leap for where they used to be. | ||
| Road_kill |
I found the speedo and odometer accuracy of my '08 Uly changed after I had the ECM update. Previous post http://www.badweatherbikers.com/cgibin/discus/show .cgi?tpc=142838&post=1243087#POST1243087 | ||
| Dio |
According to my GPS my '00 and '02 HD baggers are spot on. 4mph optimistic on my '06 X! | ||
| Zuhl |
So it looks like some folks had speedometers that were incorrect, but odometers that were okay. How is this possible? Isn't the odometer just a function of the speedometer x time. I thought they were wired together. | ||
| Froggy |
They are not linked. Your odometer will be right, I have confirmed it with a second setup that has a odometer and speedometer, and again with GPS. The odd ball is the stock speedometer, they just run high, and get worse at really high speeds. | ||
| Zuhl |
Oh, well sweet then. I guess I did get 56mpg after all! I guess I will just have to live with it. At least I know now why people were always passing me. Thanks to all for their help. | ||
| Teeps |
I have noticed the engine speed @ 80mph is lower by about 200 to 300 rpm as the rear tire nears the end of its useful life. So a new tire may increase the accuracy of the speedo on your bike. |
