Benefits and Concerns with a 120

[Jon Wildsmith]

The ODO and the speedo are driven by the same electrical pulse so they both see the same number of pulses. If your tyres are 10% bigger (circumference) then yes you need to add 10% to the ODO figure to match the accuracy of pre big tyre readings.

My assumption is that the manufacturer intentionally makes the speedo read high, there's no reason these days for it to be inaccurate to the degree they are unless it's intentional IMO. Having the ODO under read by 10% wouldn't be good though so I would expect them to indicate the correct distance on the ODO but that is just supposition on my part trying to be logical about it.

 

[Chris]

That's kinda where my head was Jon.

My Avensis had all sorts of digital gizmos and there was a button to press when you put new tyres on to rest the various calculations. I never pressed it. Actually, I never put new tyres on. Ha Ha.

Chris

 

[TonyP]

That's kinda where my head was Jon.

My Avensis had all sorts of digital gizmos and there was a button to press when you put new tyres on to rest the various calculations. I never pressed it. Actually, I never put new tyres on. Ha Ha.

Chris

In a similar wa my 120 has a option in the sat nav to reset it when there is a tyre change.... Not sure if this is just for the sat nav or if it will also effect the odo.

 

[Beau]

Beau, what year is your LC and which box do you have in it ? those figures are unbelievable !

Mine is a 1997 colorado with an automatic box in it. And when the head first went I had the complete engine swapped for a newer low mileage one, as well as a transmission rebuild and new torque converter in 2001/02 I believe. It done 150,000 miles, and used everyday. I have no mods on the engine what so ever. It is pretty much standard other than the 20" wheels and exterior mods. Im thinking of getting a D4D engine and at some point sticking it in!

 

[BIG clean GREEN]

So at 10% Steven my 21.6mpg would infact be 23.7mpg and if so that's not quite so bad and whilst towing at 14mpg it's actually 15.4 (still s4ite)

My brother the copper reckons the reason for the exagerated speedo figures are for speeding purposes and law suits Etc. against the manufacturers, which is also why most counties allow around 10% prior to prosecution for speeding.

 

[BIG clean GREEN]

Whilst driving home from Lincomb today I thought I would test out the theory that my milometer is out of true, because mine is an import the milometer reads in kilometers and the speedo in mph, so whenever I'm working the consumption out I have to do the maths, Kilometers multiplied by 0.62 = miles, so today I clocked my trip over a sat nav measured 10 miles and instead of acieving the expected 16km I only got 14.7km which when working it backwards into miles = 9.13m, that by my calculation is 8.87% out

When I got home I went to fill it up with juice, and using my old calculation I achieved 24.04mpg, however using the new calculation of 0.68km to the mile I actually achieved 26.3mpg and yes it's all motorway on the way home but we didn't exactly hang about so all in all I reasonably pleased with the end result, maybe worth someone else giving it a go over a measured distance to do a comparison

 

[Nuclear Chicken]

Chris

In a similar wa my 120 has a option in the sat nav to reset it when there is a tyre change.... Not sure if this is just for the sat nav or if it will also effect the odo.

No, that's just a service reminder schedule job to keep track of things. Nothing more. Nowt to do with the 'real' ODO and speedo.

 

[BIG clean GREEN]

"Odometer" Thats the word I was looking for