Speedo Error

[rastuscat]

No, not the Baywatch type.

Typically, when we do riding assessments, we do a quick check of the speedo on the rider's bike. This has served to confirm, as if I needed it, that speedos are awfully inaccurate on a lot of bikes.

Notably, they all seem to read at least a few km faster than the actual speed being travelled. Unfortunately, this causes people trying to stick to the limit to actually ride slower than they are allowed to.

An example of a bike I had some years back was a Gilera Runner. It was a 2 stroke, 180cc scooter, and it went like a cut cat. Trouble was, when I was doing an actual 50 kmh, my speedo was reading 70. Bloody Italians apparently like to think they are going fast all the time.

It also means that if a cop wrote you a ticket for 71 in a 50, (based on a calibrated radar or laser), it is likely that your speedo was reading well over that. Speedo error virtually always makes you go slower, not faster.

In my previous occupation I had the chance to check against a calibrated standard.

Now that we all have either GPS or an app based on GPS on our smartphone, how are your speedos looking? The new knowledge actually makes us go faster.

Just interested in your experiences.

[Akzle]

i ignore my speedometer and drive to the conditions.


shock fucking horror. i travel in excess of the posted limit.
like, most of the time.

[rastuscat]

i ignore my speedometer and drive to the conditions.


shock fucking horror. i travel in excess of the posted limit.
like, most of the time.

I expect no less of you Azkill

[nzspokes]

Both my bikes are bang on, gps checked and speedo healers fitted.

[Bassmatt]

Had a Kawasaki 250 where the speedo read 100km/h at an actual 82 km/hr, when I rode it home the first time I couldnl't work out why so much traffic was building up behind me.

[EJK]

That's why I love Germans. Their speedos are only -2% whilst other Japanese cars/ bikes can vary somewhere around 8-15%

98kph actual at indicated 100kph last time I checked. They don't joke around.

[johcar]

My Triumph Tiger XCA reads very similar to my car: 100km/h GPS reads around 105km/h on the speedo. But I'm usually traveling a bit quicker than that...

[T.W.R]

Always get my motorcycle speedos calibrated at E.Parrot & son in ChCh so never had to worry about them being out

[Ocean1]

In my previous occupation I had the chance to check against a calibrated standard.

In the distant past speedos were considered measuring instruments. The generally accepted metrological standards for such particular instruments was, (among other things) an accuracy requirement expressed in +/- % of span, (total range measured). So your Smiths instrument of mid last century was likely to be required to be accurate to +/- 5%.

But. Some ravening socialist Euro bureaucrat noticed that this meant that a speedo COULD read less than actual, allowing the completely unsuspecting driver to EXCEED THE SPEED LIMIT!!!
By up to 2 1/2 MPH!!!
WITH COMPLETE IMPUNITY!!!

Now as we all know that's a certain death sentence. Not to mention a red rag to that particular flavour of bureaucratic bull. So the the merely scientific requirements were arseholed in favour of a far more regulatory set of... regulations. All speedos now had to be "accurate" to +zero/- [some irrelevant number buried in the reg's and mostly untraceable].

Also, car makers aren't silly enough not to notice that their clients are. Silly. In particular they noticed that they sell more cars if the speedo reads at least seven times the legal speed limit and at least three times what the vehicle is capable of achieving, short of a full compliment of JATO rockets. Ideally, from the perspective of a car market annalist's point of view the speedo should be carefully callibrated such that the local speed limit is sufficient to jjuuuuust make the needle jiggle around a bit, but only in order to indicate that the client is, in fact moving and, in theory should maybe pay some attention to shit.

The combined result of these stunning examples of governmental failure to mind their own fucking business resulted in speedos that don't actually tell you what speed you're doing. Which would be a complete disaster if any of us actually read them.

[neels]

Speedo in the german car pretty much bang on, the italian bike give or take a needle width.

Only had one that read lower than actual speed, in an old fiat, wondered why everyone was driving so bloody slow.

I check them all against the GPS now, so at least I know what they're out by.

[Jeeper]

Speedo over reading by 5% means that when the warranty expires at 100k, you have actually only covered 95k. Consumers are shortchanged on warranty as well...

[Akzle]

Speedo over reading by 5% means that when the warranty expires at 100k, you have actually only covered 95k. Consumers are shortchanged on warranty as well...

[Jeeper]

Indeed its a conspiracy.

[Laava]

That's why I love Germans. Their speedos are only -2% whilst other Japanese cars/ bikes can vary somewhere around 8-15%

98kph actual at indicated 100kph last time I checked. They don't joke around.

Part of that maybe due to shaft drive being far less likely to ever have it's ratios altered. On my first v strom, when I changed the sprockets by 1 down on the front and 2 up on the rear, it was ridiculous how far out it was to the point where I had to fix it.

[caspernz]

Both my bikes are bang on, gps checked and speedo healers fitted.

Ditto ^ for the reason below cause I'm a Dutchie...

Speedo over reading by 5% means that when the warranty expires at 100k, you have actually only covered 95k. Consumers are shortchanged on warranty as well...

But yep, like Rastus mentioned, most speedos are optimistic. So when you get pulled over for 110, your speedo would have been 5 or 10 above that again...