Hyperactive Speedo Needle?

[Spitting Bull]

I changed my speedo cable yesterday and this reminded me that I had meant to ask this question here.

I know that at speeds of 40 mph and above, my bike's speedo reads about 7 mph higher than the actual road speed.  This shouldn't be too much of a problem, because it should be possible to work out actual speed by looking at the speedo and subtracting 7 mph from the indicated speed.  The problem is that an anything over an indicated 50 mph the speedo needle is dancing around all over the place, so it's impossible to even get an accurate indicated speed to work from!

Most UK riders I've met or been in touch with have the same problem.  Just out of interest -  do your US bikes have this problem, too, or is it something that has been ironed out on the way to the customer.

(UK solutions include buying a replacement speedo which has been correctly calibrated or fitting a cheapo bicycle speedo and just using the bike's speedo to record miles covered.)

Tom

[baird4444]

Tom- while my U.S. speedo in generous- 63mph indicated = 58mph actual;
I have not heard to much about bouncing needles. Could it be the KPH models
have  with the affliction??
             - Mike

[RagMan]

It is a common problem. The cure is to open up the speedo, gently clean it out with something like WD40, gently blow out any muck in the unit, get a GOOD quality speedo cable, take it apart, clean and lubricate it, then put everything back together again.  You then have a rock steady speedometer.

[Spitting Bull]

Baird444 - mine is indeed a km/h speedo.  Original equipment.  So was the old cable.  The new one is an English-made one and the needle seems to be behaving itself a little better with that one.

IB - I will take the speedo apart and check it over as you suggest, probably some time over the winter.  First, I will have to fit a new front tyre, and while I have the wheel out I can see how I can re-position the speedo drive to give the cable an improved line from drive to speedo.

Of course, what I'd REALLY like is one of these calibrated replacements, based on the 1950s Smiths product

Tom



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