Speedo error

[Geekay]

Just for interest I took my hand held GPS which has a speed reading, to test speedo accuracy.

At 110 kmh on the clock, actually doing 103kmh.
To get to 110 kmh, speedo read 118km.

As this is within the 10% design tolerance I gather MM dealer wont adjust it (assuming they can).

This is good, now I can go faster

[Eastie]

Found exactly the same thing (cooper ATR's).

[subi_man]

ML Tritons are the same, fixed mine by fitting larger diameter tyres

[peterdeg]

For my NP there's a 5% error. eg. 100 on the gps shows as 105 on the clock.
No wonder I was always holding up traffic.

[Scar]

I can confirm similar sort of results.

Made an effort last weekend to look at speeds on Speedo and speeds reported on Navman.
Speedo at around 100km always seemed to be about 5-8km less than the Navman.So sitting on 110Km on speedo and navman said about 102 etc.

On my next trip I have thought about taking navman and gps and seeing how close those 2 are in speeds.

It would be interesting to see how close 2 GPS systems are.

Cheers
Jason.

[Mike DiD]

I've had Pajeros from 1990 Generation I to the NS - they've all had similar speedo error.

[Para Ordnance]

You will find 80% of vehicles on the road have that issue. Unless it's a highway patrol car, or been calibrated by a speedo place, there will be some slight difference in speed on the speedo!
Although, it's an issue and fault if the speedo reads 90klm p/h and your GPS reads 100klm p/h.

[Wal]

Just for interest I took my hand held GPS which has a speed reading, to test speedo accuracy.

At 110 kmh on the clock, actually doing 103kmh.
To get to 110 kmh, speedo read 118km.

As this is within the 10% design tolerance I gather MM dealer wont adjust it (assuming they can).

This is good, now I can go faster

This matches exactly what my speedo does (also checked by both GPS an those radar displays you sometimes come across). At least I now know how fast I am actually going so why change tyres?

[Esteban]

Have done the same check with my GPS , however with the 265/70/17 ATR fitted on my vehicle expected the speedo to be in error by at least 5km/ hr below what it should be. GPS shows 110 Km - my speedo shows 114 Km. Bigger tyres better accuracy mm....

[jmi]

I spoke to my dealer about the speedo error and they said that it is within the Australian standards and if i am still not happy speak to MM. So i sent them off an email and i was told to speak to my dealer.
So back to the dealer i go and they basically said they could do nothing unless MM told them what do to.

Has anyone else tried to get this fixed??

Pain in the bum with incorrect readings.

Josh

[matthewfnorbert]

if the ecu software is friendly like say the GM ecu' (commodores etc) then it is as simple as changing a field in the ecu program... so if you know anyone who can modify the ecu program (like say an evo boy racer tuner shop etc) then they may be able to help you.. these guys have all sorts of after market ecu tuners... for eg. the holden/chevs use "efilive" "hp tuners" just to name two.

[jmi]

Surely my dealer must be able to change this? or at least MM do it and then send it up to my dealer.
Oh well i will just get some bigger tyres.

Thanks for the replys guys.

[matthewfnorbert]

bigger tyres will of course fix the speedo but may also make a noticeable different to performance (read sluggish) in some gears if the size is changed enough to fix all the speedo error..

[danc12]

Don't forget the ODO

For me the bigger problem is that my Odometer will under read the number of Km's actually done. For those of us on a lease where we are required to do greater than 25,000 km's per year to get hte tax breaks it can be a financial hit.

[jmi]

Yeah good point Dan.
Mines not on a lease, but there are plenty out there that are.
I am still trying to get answer from MM so see what happens.