Anyone know how accurate the speedometer should be? I always thought the HD speedometer was highly accurate. Mine reads 4% to 6% faster than what my GPS displays.

I ride with a buddy who has an 03 dyna wideglide. His speedometer reads 70 when mine is reading 75.

Is there any way to adjust it or would replacing it or the sending unit possible change anything?

 

The speedo's aren't calibrated like you would think.... They are working off of electrical pulses.....

Another thing to consider, are you running a zero fitment tire at the correct pressure?

 

I noticed the same thing on my 06 FLHTCUI. My 95 flhtc was always on the money.

 

I checked the speedo on my SG with a GPS, and it was within a mile or so of being on the money.

Bob

 

Around here the LEOs have radar stations that show the speed limit and your speed. I have checked my speedo at several of them and when my indicated speed is 35mph the radar machine says 33mph which is about 6% errorl

 

S&S makes a module to adjust your speedo calibration. Forgive me for not having more info on it at hand. Seems like it runs around $125.00. If you can't find anything on it, I'll look it up in the book.

 

Thanks Derek,

Found it http://www.sscycle.com/temp/instruct...et/51-1056.pdf

Simple adjustment. I'm getting new tires next week so I'll be sure to check pressue and all.

Thank to all,

Bob

 

The "Your Speed Is" radar trailers are not 100% accurate. First of all, any radar is only within 1 mph accurate if you are travelling directly into the beam of the antenna with no angle (cosine). As your angle into the antenna increases, the accuracy of the reading will decrease proportionally, always in favor of the driver. The "Your Speed Is" radar is not calibrated or tested, since it is not used to enforce, and may be a couple mph off. If your concerned, the best way to test your speedo accuracy is on a dyno. That is how LEO tests the accuracy of police speedo's monthly. They should be able to give you accuracy at 5 mph increments or so.

 

All speedometers are off from the factory.

There is also a thing called the Yellow Box that fixes the speedo.

http://www.blackrobotics.com/ I've used it before with great results on my sportbikes and others that I know.

 

I run a secondary speedo, believe it or not I use a biycycle computer on my Kawi.

superglue a magnet onto the rotor, attach the sensoe with an O ring, measure one full revolutio of the tire in centimeters, and it is super accurate to 170 mph

cost? 19 dollars.

Sigma BC-800 bike computer also records top speed, elapsed time and distance and is a clock!