Installed a new rear tire Friday (Dunlup Elite 3 160/80B16 80H), but now state trooper told me my speedo is off by giving me a speeding ticket (I said 62 he said 72). How do I correct this problem? Can I correct the tire size with the SERT, or do I need Harley dealer do this?

Thanks for any help or suggestions in advance. Vinny

 

Changing to a larger diameter tire will make your speed read slower than you are actually going but 10 MPH at 62? The cop needs to get his Radar gun calibrated.

 

That's what I was thinking, but I just installed my birthday present, so I just wanted to get back on the road and ride. Later that day I went by one of those signs that gives you your speed and it said 49 and the speedo was at 42 - that's 7mph difference.

 

thats about right bigger dia tire will travel farther per rpm= faster than speedo reads, mine is off almost that much stock get a gps and youll find most harley speedos off by about 5 %. dont know if sest can calibrate it but thundermax does have that feature.

 

Check it with a GPS. If you don't have one borrow a friends. You'll get your true speed.

 

Check your speed with a GPS before paying ticket/going to court....most Motorcycle/Automobile/Boat speedometers are notoriously inaccurate...BUT usually not by 10 MPH and most read faster rather than slower...good luck in court

 

So,who says the "one of those signs that gives you your speed" was accurate?...:>)

 

Speedo inaccuracy would be expressed as a percentage. So 7 off at 42 could easily be 10 off at 62. Most stock set ups run a bit off, showing higher speed then you are travelling. All this said I would take it to court. State your case respectfully and they should give you some slack unless you have a record a mile long!
On another thought if say the posted limit was 55 you are screwed by your own admission that you were doing 62.

 

Tennesse trooper told me that if i could prove my speedo was off that the judge would be lenient. it was a 4 hour drive back to the court so it was more economical to pay it than explain it.

 

They do. At the beginning and end of every shift.