I recently hooked up a GPS on my 2000 FLHTCUI, and noticed that my speedometer is off by about 10%. Im pretty sure it has original sized wheels/tires and is basically stock. Are they traditionally inaccurate???. Is there an easy fix? Thx

 

Usually its about 5%, by design. Most manufacturers dont want to be responsible for speeding tickets.

Some tuning devices allow you to calibrate your speedo, for example the Powervision has this capability, others may as well.

 

The speedo on my 09 is off by about 3kph.When it indicates 103kph,the GPS is indicating 100kph.

 

Keithhu is right, every Harley I've ever owned has been 3.5 to 4 mph optimistic. It's not a big thing, but a little annoying. One of the things I enjoyed about installing the ThunderMax Auto Tune was being able to correct the speedo. Mine is dead accurate now. Having the bike run great without depending on some guy at a dyno is the major plus!

 

It's tradition, they are still that way.

 

But you guys are talking 3-5%. At 70mph on my speedo...Im actually going 62 on GPS. Mileage is consistant......on a 100 mi trip, I log 111. Seems like alot to me.

 

My Speedo is off too. Only about 5% though. As said earlier,most manufacturers build in an error to the speedos for liability.

 

Just went through all this with the dealer and what is cover under the warranty for them to fix it. Basically if you are reading under the speed limit. Example you are going 67 and it shows 65 will be fixed by them. BUT if it is saying you are going 65 and you are only going 60 it will not. It has to be a 6mph difference on that end which I think is BS and unacceptable. Was not happy. Mine is 5mph slower than I am actually showing.

 

tire wear and pressure will affect it as well.mine starts about 5% off on a new tire and 8%when tire is well worn.

 

Try riding with some Honda's and Yamaha's. They are consistently 10-15% off and it drives me nuts! Dad has a Honda, Step Mom has a Suzuki, and wife has a Yamaha. They NEVER go faster than 50 so I can NEVER get into 6th when riding with them. I get in front and TRY to ride 55 and they all scream at me to slow down, "we aren't going to ride @70mph"! REALLY? We get passed by grannies in their grocery getters and it drives me NUTS!

I put the GPS on theirs and proved that @ 60 mph on the GPS, they are showing 75 on the speedos. They are consistent with each other, so I tried a second GPS and they are still all off by the same degree.

My Heritage shows 58 @ 60 on the gps so I am still a little off, but not bad.