[waspmike]

Is this true? Is the speedo inaccurate with a 14T

 

[Lacsapix]

When compared to a 13T, the math says its a 14/13*100-100=7,7% speed increase. If getting the speedo accuarate is your main objective there are other options that do not change the handling of the bike, like this healtech thing.

 

[JRW2007]

if you don't like the torque loss, this device works well. I have it on my 650.

Speedometer Calibrator

 

[waspmike]

So nobody knows then?

 

[Pekes17]

The speedo is only made accurate if you increase the circumference of the rear tire.

 

[Pekes17]

And that's because the speedo works from the rear wheel rotation sensor. So you can change the gearing all you want, it won't change the RWRS. A larger circumference rear tire will trick the speedo, making the bike go faster than the speedo thinks. Therefore since the speedo is naturally optimistic, a larger rear tire will render the speedo more accurate. A 130/90 or a 140/80 will do the trick.
The downside of the larger circumference rear tire is then the odometer will be pessimistic, or understating the mileage.
I've tested this with my bike.
One more thing...it does NOT affect the handling of the bike.

 

[waspmike]

OK I thought it got the signal from the sensor on the front sprocket so changing from 14T to 15T would make a difference.

I tried to inspect my bike but too many panels to remove.

 

[fasteddiecopeman]

I read my TRUE speed on the GPS on EACH of my two V650s!