M1100 speedo showing 20% to fast.

[Italiatwin]

2009 M1100, 14/39 gearing, standard wheels and tyre sizes.
Speedo reading 80 at 4k, should be reading 67 according to Gearing Commander. I am aware the speedo should or could read 8% to fast but 20% seems excessive.
Any thoughts ?

[rollo22]

Speedo is read from the rear wheel sensor.
Mine does read fast at that speed.
Try using sat nav to confirm the error.
At least you won't get pinched for speeding.

[Dirty]

Tyre pressure + 8%?

[Italiatwin]

Hmmm, interesting thought.
I have 35 psi in the rear at the moment BUT I don't know how accurate the petrol station tyre pressure machine is.
That gives me something to check.

[rollo22]

Isn't the standard front 15 teeth

[Dirty]

In addition to tyre pressure the weight of rider will have a small effect.

[Italiatwin]

What you trying to say........😂 Lol.

[Darren69]

Excessive sag, lol! I suffer the same problem :)

[SunEye]

Isn't the standard front 15 teeth
Yes 15T is the standard front sprocket on a 2009 M1100.

Maybe somone with the same bike and gearing would like to confirm what revs they are getting at an indicated 80mph. Unfortunately I don't have an M1100 anymore.

[J.P]

Standard set up is a 15 tooth front, and 39 rear. As in the manual.
If you've changed it, which you have it's clearly going to have a knock on effect. As Rollo said if you have a Sat Nav you can at least get an idea of what it really is

[Dirty]

He's comparing it to gearing commander, not to standard set up.