We have recently got a load of new Scanias.
according to the tacho they were doing 53mph, but in reality were actually only doing 51mph
we asked for them to be set up properly to 55 or 56mph
they are now coming back showing 55mph but still actually only doing 53mph
how hard can it be to get them properly calibrated and why are they not set up correctly from the dealer ?
And if these vehicles are leased on a mileage basis, how much extra are companies going to have to fork out for the false reading ?
AND, our previous volvos were the same.
rant over.
2 mph error at 50moh is 4%. So that could be a 4% hike in mileage charges.
Driving slower will usually give better actual mpg. A false reading of distance will flatter the actual mpg by that 4% we’ve already seen.
I wonder how many operators trust the figures from the truck’s own devices rather than look at genuine fuel costs?
How are you measuring the actual speed?
Trukkertone:
We have recently got a load of new Scanias.
according to the tacho they were doing 53mph, but in reality were actually only doing 51mph
we asked for them to be set up properly to 55 or 56mph
they are now coming back showing 55mph but still actually only doing 53mph
how hard can it be to get them properly calibrated and why are they not set up correctly from the dealer ?
And if these vehicles are leased on a mileage basis, how much extra are companies going to have to fork out for the false reading ?
AND, our previous volvos were the same.
rant over.
That must be boring.
Mine does 61, but it’s not brand new.
Ours, tacho reads equivalent of 55mph, speedo says 56mph and sat nav says 53mph. Which do we believe is more accurate?
Sent from my ONEPLUS A5000 using Tapatalk
Sat nav measures global position, an doesn’t take account of the contours. It sees everything as a flat sheet. The actual distance covered is always greater because of vertical distance travelled.
If you’ve ever walked the costal path in west Wales and thought ‘oh it doesn’t look far on the map’ you will understand. You go at least as far up and down as you do along.
Trukkertone:
And if these vehicles are leased on a mileage basis, how much extra are companies going to have to fork out for the false reading ?
AND, our previous volvos were the same.
rant over.
Speed measures the time it takes to cover a distance, the milage doesn’t change with faster speeds, it just takes less time to cover it.
I’m assuming the truck tacho/speedo is being compared to a SatNav reading. These are pretty accurate.
Although SatNav can give a postional error, that error will remain fairly constant, so the distance measured will be accurate. And they rely on very accurate clocks, so their speed readings are accurate. There is lots on the www about this stuff.
Getting tired legs after walking a hilly path is probably more to do with walking up and down hills than walking a further distance due to those hills,surely?
Anyway, because we’re looking at a differing speed reading, when the reading is “instantaneous” all issues with contours and heights are negated.
If these vehicles are giving this much error with brand new tyres, then we can expect a greater discrepancy when the tyres wear more. Remember speedos/tachos are counting the number of revolutions made by the wheels, usually a sensor on the back of the gearbox. It calculates the distance from a known tyre size. (Tacho certificates show tyre size). A worn, and so smaller tyre, will need to turn more revolutions to complete the same distance, as a new one, so counting revs the odometer will give a higher reading for the same distance travelled. It’s easier to visualise this if you imagine a wheel twice the size of another one, the principle holds with smaller changes.
Tachos/speedos are adjustable to allow calibrating for differing wheel tyre combos. As I understand it, it is illegal for any speedo to read slower than actual speed, but tolerance is given for “optimistic” readings.
I daresay the mechanics who post will confirm or dispute that. And maybe they’ll say what current truck company policies are on settings and tolerances?
This fast enough.
switchlogic:
How are you measuring the actual speed?
gps app and sat nav , measured between M55 junction and Forton services… a nice level 8 mile stretch
biggriffin:
This fast enough.
There goes your bonus. Did the office call you to tell you you were driving dangerously and someone could be killed by allowing your vehicle to go 5mph quicker?
Trukkertone:
switchlogic:
How are you measuring the actual speed?gps app and sat nav , measured between M55 junction and Forton services… a nice level 8 mile stretch
A gps app and sat nav are not dvsa vosa whatever hey are called nowdays approved …Tacho rollers are the only approved piece of kit …
cgscott:
biggriffin:
This fast enough.
There goes your bonus. Did the office call you to tell you you were driving dangerously and someone could be killed by allowing your vehicle to go 5mph quicker?
We don’t have pointy shoes in our office, or any interfering about silly things, as long as the works done, just crack on.
I had a DAF 105 that did 92. It was glorious to drive on the motorway. Only the occasional Irish overtook me.
Radar19:
I had a DAF 105 that did 92. It was glorious to drive on the motorway. Only the occasional Irish overtook me.
That’s the thing with DAFs, you need them going a decent speed so they don’t run out of puff trying to get up hills. 
TheUncaringCowboy:
Radar19:
I had a DAF 105 that did 92. It was glorious to drive on the motorway. Only the occasional Irish overtook me.That’s the thing with DAFs, you need them going a decent speed so they don’t run out of puff trying to get up hills.
If euro 6 then you may have eco mode ,what you say is not something that drivers say ,they are generally happy with how they pull …electrics is a different story lol ,though that has improved ,the looms are good it is now the sensors and components they are connected to that fail
norb:
TheUncaringCowboy:
Radar19:
I had a DAF 105 that did 92. It was glorious to drive on the motorway. Only the occasional Irish overtook me.That’s the thing with DAFs, you need them going a decent speed so they don’t run out of puff trying to get up hills.
If euro 6 then you may have eco mode ,what you say is not something that drivers say ,they are generally happy with how they pull …electrics is a different story lol ,though that has improved ,the looms are good it is now the sensors and components they are connected to that fail
The last DAF I drove was an old school 510 with a thing sticking out the floor, decent going steed but she was no V8.
Would I swap for my auto 730 now, no chance maybe for 164 or 143, certainly not a DAF dungbox
biggriffin:
cgscott:
biggriffin:
This fast enough.
There goes your bonus. Did the office call you to tell you you were driving dangerously and someone could be killed by allowing your vehicle to go 5mph quicker?
We don’t have pointy shoes in our office, or any interfering about silly things, as long as the works done, just crack on.
Any jobs? Pm me.
cgscott:
biggriffin:
cgscott:
biggriffin:
This fast enough.
There goes your bonus. Did the office call you to tell you you were driving dangerously and someone could be killed by allowing your vehicle to go 5mph quicker?
We don’t have pointy shoes in our office, or any interfering about silly things, as long as the works done, just crack on.
Any jobs? Pm me.
.
Fully booked up.