I think that one always needs to remember that long after the speedo has returned to 0, the GPS memory remembers that you were doing 100.

 

My speedo is dead on with my GPS readings.

All manufacturers consider a certain amount of variance to be "normal", and I've read elsewhere that H-D considers up to 10% to be acceptable. That's pretty high, though, and I haven't heard of any bikes that far off. 5% is very common.

 

I have a TomTom GPS that I use on my Ultra, and my 4 wheel vehicles. There is always a three MPH difference.

 

really a non issue. warranty on hd is by time, not by mileage.

 

Ezzackly.

The only thing affected by your odometer accuracy is how fast you get your HOG Mileage patches.

 

A few things I would add to this old thread.


I've had several Harleys, but I'll stick to the ones with electronic speedometers. Since I started using satellite GPS to cross-check speed in 2005, they have all been off except my 2015 FLHTK. My '03, '04, '09, & '11 (all touring) were off 6%-7%. My 2015 surprised me when I checked it against my Garmin and phone app GPS to find it dead on. I also corrected my friend's 2014 FLHX and it was off 6 or 7%. The point I'm trying to make here is that if your bike is 2015 or newer, this may or may not apply to you. You'll need to confirm iot for yourself.


I've not owned Sportys, Softails, or Dynas with electronic speedos, nor do many of my friends have them, so I don't know if this applies to them.


While I've used the Power Vision to correct this on 2 bikes and it worked well, I understand that the TTS will do it in pretty much the same way. The FP3 seems to have a very nice function built in to use the GPS on your phone to automatically fix it. This seems very nice and by reports that I've read it sounds like it works pretty slick too. The HD Super Tuner doesn't have a speedo correction capability that I know of.


Also, in regards to tire wear, its effect is pretty minimal. I do try to calibrate when the tire is new so that when it is at the other end of useful life, my speedo reading will keep me on the "safer" side of the tolerance window.


One last point to make about GPS speed. If you are referencing the GPS reading in your Harley Boom! 6.5GT head unit, it gets the speed signal from the same place your speedo does, so they'll both be right or wrong (although I have seen a pic posted where they didn't match, but that was deemed to be a different malfunction).

 

My 14 FLHXS is spot on I was impressed with it as my 13 was 5-6 percent off.