[English Bob]

imported post

I got fed up with my speedo being about 5% slow, so after much looking around I settled on a Speedohealer.

It cost about C$109, and included shipping. It arrived 3 days after ordering.

Installation on my '06 was easy, had to remove the top shelter to access the wiring harness, which is down near the RH heat vent. The provided harness was adequate to mount the device to the side of the gas tank under the right rear cover. Well protected but easily accessible for changing the calibration or activating the kph/MPH conversion.

There is a remote button for recalling top speed. I didn't use the supplied button. Instead I bought a momentary normally open button from Circuit City and put it in the RH fairing pocket.I also put a connector in the wire so I can remove the pocket easily.

I did initial calibration based on comparing GPS to actual speed while on cruise. I then refined this calibration by using a stopwatch over a 10km measured stretch of the Trans Canada.

I have settled on a factor of -4.8%, I imagine this will change as the rear tire wears.

Interesting note, Honda must use different factors for speed and odo, the odo being off by only 3.1%.

One of my reasons for doing this is that my pickup and the wife's van are both spot on, but the bike was off. Now they all read true speed, which I like.

 

[DaveO430]

imported post

You would think Honda's engineers could get that right, I think it's on purpose, don't know why though. The cars have the same problem and always have, they were sued and had to extend the mileage by 9% for warranty purposes.

 

[English Bob]

imported post

I don't think it is a question of getting it right, so much as being forced in to a position where they have to do it that way.

The trouble is there is always variation in measuring anything, the speedo has variation just from manufacturing tolerances, the wheels vary as new, and also wear with time and so on.

To make an example, if they built and ran a whole pile of bikes at exactly 100 mph, they would get readings from say 97.5 to 102.5 mph, the average would still be 100.

Speedometer legislation requires that speedos NEVER read less than actual speed, so all those that read less than 100 would be illegal, in order to meet this they have to put in a fudge factor.

This is also why the odo doesn't have the same inaccuracy as the speedo, because it doesn't have the safety implications, and presumably has a different fudge factor.