I Mounted my GPS for the first time on my '10 Ultra....Seems that the Ultra's Mph is off by +2MPH.. Has anyone noticed the difference? Does my Speedo need to be recalculated?

 

Mines off by -4 mph

 

They are all optimistic, mine reads 73 while the gps is at 70

 

Don't mess with it. Both of my ultras have been off by 3mph according to the GPS which should be accurate. I never even look at my speedometer just my GPS.

 

I've never seen a motorcycle speedometer that was not optimistic. They usually vary from 2 to 5 mph fast. I've only seen one car speedometer that was really accurate!

The only motorcycle speedometer that I've ever had any luck with in recalibration was a BMW that read 7 mph fast. I managed to get that one within 1/2 mph optimistic.

My FXR is 4 to 5 mph fast, & my Road Glide is about 3 1/2 mph fast. Both within acceptable limits. It allows me to believe I'm a little fast even in well patrolled areas, but be close enough to avoid tickets.

 

The speedo on my 08 UC shows 5% faster than my GPS shows across the board. it it very consistent though so I know how fast I am going. For example if the bike speedo shows 60mph the GPS will show 57 mph. 30 MPH is really about 28 MPH and, not that I would know but 90 MPH would actually be about 85.

Also the odometer is also off as compared to the trip function on my Garmin GPS. It will also show more miles traveled on the trip odometer than the GPS odometer. I guess they match as the speedo shows I am going faster so I must also go further? Just did a 200 mile ride yesterday so I need to look to see if that is also 5%.

 

Same thing with mine. GPS shows 3 mph slower than the Ultra speedo.

Or for the right hemisphere thinkers, the Ultra speedo shows 3 mph faster than the GPS....

 

They all do that.

Sorry, couldn't resist.

 

Nearly all bike speedometers are off by 2 to 5 mph. It can be adjusted if you have SEST or TTS Mastertune.

 

I don't have a GPS on my RK, but according to the Florida Highway Patrol mine is dead on....