Inacurate Speedo

[Ivan]

As it turns out, my speedo is about 6.5% fast. In 10 miles, My odometer shows between 6 and 7 tenths more than should be.

I have an 81 special and it has a 160 speedo, I am not sure if it is stock or not.

First things first, what should the stock front tire size be?

Next, are the speedo drive gears replaceable with ones that have more teeth, like on an older vehicle?

Amy other ideas on what may be causing the discrepancy?

[Dennyz]

I found that it is pretty common for the speedo on the XS to be off (fast). So, we are not going as fast as we think we are.

I went to a bike computer to get accurate speed and distance numbers.

[Paintman]

Speedos

I set up My GPS on mine and run with it always accurate but now i dont get lost.

John

[TopCatGr58]

Hey Ivan,

Right, 160 mph speedo is NOT stock for 81, the EPA 85mph WAS!

Front tire size can vary depending on brand, but I remember about 26" total diameter sounds close!

You can't swap speedo drive gears on our bikes.

There are sites that offer calibration services!?

The cheaper way is like suggested, get a bicycle one to ADD to your machine.
T.C.

[Ivan]

Hmmm.

I guess I can learn to live with it. If I drive the advertised speed limit on the speedo, I get lots of people passing me. That just won't do.

As fast as these things are, maybe an airspeed indicator from a Beechcraft is more the answer.

[Crazcnuk]

Yes, but now you can drive 10% over...safely!