How far off is your speedometer

[trapper]

I was running at 80 MPH by my GPS and the speedometer was at 87 MPH. I was just wondering if anyone else has checked the difference on their bike. I knew the bike speedometer was fast but 7MPH seems a little extreme.
Trapper

 

[R3 Guy]

When checked using a gps, I find an approximate 10% difference in actual vs speedometer. Pretty consistent throughout all speeds.

 

[DRMD421]

I was running at 80 MPH by my GPS and the speedometer was at 87 MPH. I was just wondering if anyone else has checked the difference on their bike. I knew the bike speedometer was fast but 7MPH seems a little extreme.
Trapper

Same here. I quit looking at it and just try to keep in front. It's more fun that way, especially on the highway...

 

[TRath]

I was out about 11-12% until I put on the Bridgestone Exedra 240/55. With the extra sidewall height my GPS only has me out about 1% on the highway.

 

[hegels]

I'm about 10% off too. I changed it in tuneecu but that messed with the odometer and I didn't like that so I put it back.

 

[cootertwo]

Someone from Triumph told me that the speedos on the Rockets are 6% fast. I set mine back 4% with tuneEcu, and according to the roadside speed radars, it's about 1 or 2 mph fast still, so the 6% must be close.

 

[barbagris]

Beats me why "dead-reckoning-GPS" has still not been adapted into speedos. i.e. use GPS to auto calibrate speedos.

 

[TURBO200R4]

10% IF YOU WENT BY SPEEDO YOU would never get a ticket!
herman
but who looks at speedo?

 

[ozrider]

I also didn't like the idea of a higher odometer reading that could effect resale so I fitted a Speedo-Healer v4............... you can reprogram the offset, K's to mph converter and recall max top speed.

check it out at HealTech Electronics.

 

[mr hunt]

mine appears to read about 20% on the low side.

The officer said 96kmh, I said 'I swear my speedo said 80, this IS an 80 zone right?'