I calulate distance over time using the dash (tacho) display and I get 90 km/h like the tacho chart.
What bloody one is correct?!?!?!?
There’s a sticker next to the gear stick saying something like Vitesse Fixe 85 km/h (fixed speed 53 mph)
How fast am I really going? I match all but a rare few trucks and can pass a good few on level ground. Suppose I could blast past a speed camera to see but that’s not the best idea lol
Something I learned whilst at Staveley Chemicals
“Never believe an instrument”
Personally I would say that they are all within tolerance but without calibrating individually who is to say which is correct. I dont know where the tacho gets its signal from.
After a trip from Chippenham to Norwich i was 16miles short when i had to stop for my 45min.
Tacho head was “clocking” 56mph on the limiter/cruise control. On return trip i fired up the Sat Nav on Autoroute 07, it showed my road speed as 52mph.
This explained the 16mile shortfall on the previous trip.
When i spoke to the fitter when truck was in for service he said he would look into it for me.
It was down to the tacho not being calibrated correctly. It was “hitting” the limit early as the road speed on the wheels was 52mph. This was outside the limits.
How can you be done on tacho evidence if it is incorrect ■■
ie road speed at wheels is 40mph …
tacho puts you at 44mph !!
ok , that is the 10% margin but this proves tacho’s are not the be all and end all !!
Sat Navs / Trackers are far more accurate these days, so i would be inclined to believe them over a speedo…
In fact my Navman shows a speed differnce of 5mph against my cars speedo…
Car shows 75mph
Navman shows 70mph
Speedo relys on wheels and cable…
Navman relys on up to 13 satellites…
it can also depend on whether the correct charts are being used in the tacho head, not all charts are the same.
ah, happy memories of a couple of hours sat at cluses peage with a gendarmerie sergeant trying to explain to a very ignorant and stupid english
driver that he had the wrong cards for the tacho he had in.
he must have liked me though because he took me for a nice ride in his van to buy the correct ones from his brothers garage, waived his usual fee for stopping my vehicle and fondly patted me on the back as he wished me bonne route
i have had a soft spot for the gendarmerie all through my career because of that sergeant, and i wish i was still that naive
the german police-bag will take 6kmh off a reading
of the speed trace from your tacograph, as they belive
due to wear and tear (use) it can not be totaly accurat,
however when you get your picture taken(speeding),they will only
deduct 3kmh from the shown speed,as the speedcameras
are more efficent,
the point about using the right disk for the type of tacograph
fitted in your truck, is one that can be very expensive,if you
are caught out, not all poilce are so nice as the one mentioned
by,biggusdickusgb,
Coffeeholic:
it can also depend on whether the correct charts are being used in the tacho head, not all charts are the same.
That reminds me. I just bought a couple of spare digi rolls to keep in my bag. They are marked up with E numbers. Are there any variations to the different makes?
It said something like suitable for E3 E17 and E81
Coffeeholic:
it can also depend on whether the correct charts are being used in the tacho head, not all charts are the same.
That reminds me. I just bought a couple of spare digi rolls to keep in my bag. They are marked up with E numbers. Are there any variations to the different makes?
It said something like suitable for E3 E17 and E81
No idea Malc. the paper I am using in a Siemens VDO is marked e1 180, e1 84, e2 25 and 29, and e5 0002 . There should be a sticker on the unit somewhere in the paper drawer that will give you the ‘e’ number so you can check if the paper you have matches this.
dambuster:
I’ve always been ubder the impression that you couldn’t be nicked/acquitted on Tacho alone.
I was just about to post that a tachograph disc cannot be used as evidence of speeding. I guess that’s why the new digi ones don’t seem to print out a speed trace.
