Odometer Accuracy
Road Master
Joined: May 2010
Posts: 855
Likes: 14
From: thomson, il
find you one of those l.e.d "your speed is this" signs they put along the road.. usually by construction and test your odometer that way.
there is one along 84/20 in galena, il on the rite as you head south just out of wiconsin.. may entail another roadtrip.. lol
there is one along 84/20 in galena, il on the rite as you head south just out of wiconsin.. may entail another roadtrip.. lol
Road Captain
Joined: May 2011
Posts: 710
Likes: 7
From: Colorado
I suspect the speedometer / odometer reading on my new 2011 RKC registers high as well. Is this something that can be calibrated?
Outstanding HDF Member
Joined: Aug 2011
Posts: 2,095
Likes: 11
From: Central Illinois
Its about $100, but you can dial in the adjustment to be *perfectly* accurate as long as you know exactly how far off your bike is now.
They are very common on sportbikes because those guys are often modifying their gear rations (-1 in front, +2 in the rear will give you about an 18% error on most bikes, but allow almost any 600 to power up the front wheel in first without clutching) and they want to be able to actually use their speedo.
Extreme HDF Member
Joined: Dec 2007
Posts: 13,402
Likes: 941
From: Illinois
Odometer readings not linked to speed readings. My 10 Ultra is 3 mph higher reading than my son's 06 Street Bob. His is spot on with the radar trailers that are set up in various areas.
On our long tours our trip odometers have never varied a tenth or two and many times are exact.
On our long tours our trip odometers have never varied a tenth or two and many times are exact.
Outstanding HDF Member
Joined: Aug 2011
Posts: 2,095
Likes: 11
From: Central Illinois
Odometer readings not linked to speed readings. My 10 Ultra is 3 mph higher reading than my son's 06 Street Bob. His is spot on with the radar trailers that are set up in various areas.
On our long tours our trip odometers have never varied a tenth or two and many times are exact.
On our long tours our trip odometers have never varied a tenth or two and many times are exact.
For example, on basically all Yamaha bikes, there is a sensor that measures rotation of the primary drive shaft, and both speed and odometer outputs are calculated from that.
Are you absolutely sure that they are not linked for any model of Harley? The measured difference in speeds could be an offset, it was an offset in the speed calculation, that would not prove that the two are not linked.
Road Warrior
Joined: May 2009
Posts: 1,945
Likes: 4
From: Victoria, Australia
Dealers like the odo's that over-estimate, as the service interval comes around more quickly. Only applicable if you spend your $$ there... :->>
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Stellar HDF Member
Joined: Nov 2007
Posts: 3,364
Likes: 110
From: Mesa, Az.
Odometer readings not linked to speed readings. My 10 Ultra is 3 mph higher reading than my son's 06 Street Bob. His is spot on with the radar trailers that are set up in various areas.
On our long tours our trip odometers have never varied a tenth or two and many times are exact.
On our long tours our trip odometers have never varied a tenth or two and many times are exact.
Road Captain
Joined: Jan 2009
Posts: 566
Likes: 7
From: Seattle, WA
I'm sure what you say may be true for Harleys, but just FYI, on many other makes of bike both are linked.
For example, on basically all Yamaha bikes, there is a sensor that measures rotation of the primary drive shaft, and both speed and odometer outputs are calculated from that.
Are you absolutely sure that they are not linked for any model of Harley? The measured difference in speeds could be an offset, it was an offset in the speed calculation, that would not prove that the two are not linked.
For example, on basically all Yamaha bikes, there is a sensor that measures rotation of the primary drive shaft, and both speed and odometer outputs are calculated from that.
Are you absolutely sure that they are not linked for any model of Harley? The measured difference in speeds could be an offset, it was an offset in the speed calculation, that would not prove that the two are not linked.
The speedometer is driven by a small electric motor (generally a very precise stepper motor) instead of the old-style spinning cable, but the actual mechanism is still a magnetic cup and hairspring. Manufacturing variances can result in very slightly different resistances from one hairspring to the next which can cause two speedos to read slightly different speeds even when receiving the same pulse data from the speed sensor in the transmission.
As far as the OP's observed variation, it is, at most, a 2.7% difference from one bike to the other, which is small enough to be something as simple as differing amounts of tire wear, inflation pressure, or even bike loading.