Speedo well inaccurate

[marlboro]

Just fitted an Origin B2 and compared its speed measurement to my speedo:

B2 40mph - Speedo 47mph
B2 80mph - Speedo 92mph

I thought speedo's were not meant to more than 10% out.

[PhillWalden]

Mine was at least 20% out when I got it.. Had the sender on the rear axle replaced, which fixed the problem..

[over_the_hill]

Speeds shouldn't be more than 10% out as a general rule, but when has that ever been rigid.
They are usually calibrated accurate at 30mph and will
drift out as speed increases, although they are designed/calibrated so that they will never read lower than your true speed.

So if you are "done" doing 47mph in a 40mph limit (your speedo will probably be showing 55'ish) don't start crying about it. Also, don't risk the "my speedo says 78mph so it is probably really doing 70mph" approach as you can also come unstuck.

[joospeed]

profile says u have an early chim, so there's a rheostat/pot on top of the speedo to calibrate it .. your dealer should be able to do this in about an hour (jack car up / remove dash top / drive in 4th gear / calibrate at 21mph per 1000 revs / refit dash / drive car out of workshop)

[kevp]

The Speedo rules that all cars must comply with.
You can actualy use a push bike speedo ( I have in past), dirt cheap, deadly accurate, but must be illuminated for night use.


1. The vehicle shall be fitted with a speedometer
capable of indicating speed in mph at all speeds
up to the design speed of the vehicle and
capable of being read by the driver at all times of
the day or night.
2. For all true speeds up to the design speed of
the vehicle, the true speed shall not exceed the
indicated speed.
3. For all true speeds of between 25 mph and 70
mph (or the design speed if lower), the difference
between the indicated speed and the true
speed shall not exceed -
V/10+6.25 mph
where V= the true speed of the vehicle in mph.
This item shall not apply to
vehicles having a maximum
design speed of less than 25
mph.