My bikes speedometer was off by around 4 MPH, When comparing it to a GPS and the radar signs the local PD sets up occasionally. It has been this way through 3 sets of 402's. I changed over to the E3's and now my speedo is on the money.
Has anyone else noticed this after they changed tires.

 

The Dunlop site has the actual tire circumference listed for each tire. A smaller diameter tire will increase your revs slightly, and "speed up" your speedometer. A larger diameter will decrease the revs, and "slow down" your speedometer. As your tire wears, your speedometer reading will change slightly, showing a higher speed than when it was new.

Your odometer reading may also be off. On our Ultra, it's off about .5 mile+ per every ten traveled. That's a five percent error.

Here's the chart for the E3's

http://www.dunlopmotorcycle.com/tire...tire.asp?id=86

Compare it to whatever Harley tire was stock for your bike.