Speedo Calibration

[fiiish1987]

I've been riding through those temporary speed sensors recently which show your speed if you go over 30 and kept getting told I was doing about 34mph when my speedo was reading 30.

To double check this I had a friend ride in front of me who would ride to 30 then wave his hand, then 40 & 50. I noted that my speedo was about 4mph slower each time.


Obviously Iit's nice to know what the real speed is when I approach cameras; not such a problem for me as I know to drop 5mph, but there's always going to be one day when I don't.

Tyre pressure is fine and there's plenty of tread on the front tyre so it's not like it's running on a different radius.

Is there a way for me to calibrate/adjust the speedo to get it down to the correct speed (adjust the needle perhaps?)?

Many thanks,
Si

[christhedivvy]

might be worth getting a new speedo drive unit?

[bobh]

My first 600N speedo always seemed to read a bit slow (which is illegal, btw). Just learned to live with it - provided you keep under an indicated 30 you'll be fine.

But also bear in mind that most speedos on bikes read anything from 5-10% fast (Hondas and Suzukis tend to be more optimistic than Yams, Kwackers or Beemers, in my experience of sitting behind IAM associates) so when your mate was riding at an indicatied 30 it was probably nearer 27-28.

Also these speed readout thingies also tend to be optimistic, so as not to confuse drivers by giving a significantly different reading to their speedos.

A satnav (on a level road) is the nearest you'll get to an accurate calibration.

[fiiish1987]

yes I know most are optimistic but for some but this is reading slow, and I can live with it, but it jsut one of those things I'd like to fix if possible... along with welding a new foot bar on the centre stand, sorting the infamous rattle, upgrading the brakes etc etc :-D

[amorti]

If the front tyre is over sized, that would confuse things. Should be a 110/80-17. A 100/80-17 would also fit and be about 2.5% smaller, so reduce your speedo reading. Depends if it's a constant error off zero, or a percentage error. If it's a constant error from zero I guess you could ping off the needle and reset it on its pin, but I wouldn't bother.