Ducati Sporting Club UK > Model Specific - Discussion, Technical Problems and Help > 998 / 996 / 916 / 748 > Speedo Readings

[webbyc]

So how accurate are Ducati clocks?

To give some examples - riding down to the ferry I kept a steady 90 indicated - Robin behind me on a Busa said that he never showed under a ton (now I know that we shouldn't be doing these speeds but it was early and we were chasing a ferry - no excuse though).

Another example - following an SP2 and Gixxer750 in Germany, both of them had an indicated 160, whilst my 996R never indicated more than 145.

So who is right? I have heard that Suzuki clocks do overread.

[dickieducati]

the clocks on my 999s overread by about 8% i would guess other ducati's are roughly the same.

[m1keyp]

I have a sat nav mount for trips to Europe and the speedo v the sat nav is scary.

The speedo over reads badly (2002 748)

If time allows I will do a 30 50 70 100 speedo v sat nav check this weekend and let you know

Mike

[rockhopper]

I dont think speedos are allowed to under read - all the ones i have tested with my GPS over read, it usually gets worse the faster you go.

[Clippy]

Mine read 90 when the digital speedo on the new Merc following me read 81/82 all the way along a 15 mile run.

The most accurate speedo I've found on a bike was on the RSV Mille - that was reading 143 when my mates SP1 was telling him 165 and we were acctually doing about 140 (on a closed road/autobahn/racetrack of course!). No wonder Honda riders have a few tall stories to tell!

Giles

[baylissboy]

The speedo on my Foggy rep under red by 10MPH,when compairing it to other bikes on a ride out!

[Mr_S]

When I first picked up my 748 I didn't believe the speedo, thinking it was reading way too high (20-30mph)

I did a GPS comparison on a straight (and flat) piece of road, and the result was consistent in that the speedo read about 10% over, all the way up.

Rockhopper's right that they can't under read, only over read as EC Directive and the ECE Regulation lay down accuracy requirements to be applied at the time of vehicle approval for speedometers.

These requirements are that the indicated speed must not be more than 10 per cent of the true speed plus 4 km/h. In production, however, a slightly different tolerance of 5 per cent plus 10 km/h is applied.

The requirements are also that the indicated speed must never be less than the true speed.

[rockhopper]

Of course if you change tyre sizes then the speedo calibration will be messed up as well unless you keep the same rolling radius.

[weeveetwin]

I guess this also means that when your clock says your bike's covered 10,000mls, its really only covered about 9,000!

[AK]

Webby - this could account for the day you & Alan came back from Kent together - and he was having to consistently travel at 100 - 110 to ride with you (not too much fun on a monster on the motorway for quite a few miles, and his arms had been stretched like a monkeys by the time he got home) - you said you hadnt been over 90 that day.
Alans Lawson consistently reads 17% less than the speed he is actually doing.

We usually use my bike as the 'speed guide' when each creation gets put on the road.

C