Speedo question?

[Keeno]

On the Christmas driving trip I had a gps navigation system for assistance. What I discovered is my speedo is over reading, at 100kph the speedo reads 107kph.

So my first question is can the speedo be calibrated and can I do it?

And secondly for all the 95 GLS turbo diesel, manual gearbox, 265/70R15 tyres and 4.9 diff equipped vehicle drivers what is the tacho reading when you are traveling at 100kph?

On another note I?m still getting 10.5 litres per 100 kms, got to be happy with that.

Cheers to all.

[Mad Mac]

I was about to post the same question myself. My situation is the other way around, reads, 100 on the Speedo, but the gps says I?m doing 110.

I went from 235/75 r15 to 265/75 r16.

I remember reading on the old forums that there was a Speedo gear that you could buy from Mitsubishi, with reference to this site..... http://www.mitsu4wdclubqld.org/tips/tech/tech9611.htm

You just had to work out how many teeth you needed.

But as to where you actually put the gear, I?m not sure.

But i'm sure someone will be able to help us out.

Shane

[Rusty]

How accurate is the GPS??
We have a PDA with GPS and I would not rely on it at all, despite what "everyone" says. Our unit records up to 8 metres or so movement even when the vehicle is off and stationary.

[Jaydee]

And secondly for all the 95 GLS turbo diesel, manual gearbox, 265/70R15 tyres and 4.9 diff equipped

That's 5% bigger than the 235/75/15 cheese cutters it was designed for.

100 on the Speedo, but the gps says I?m doing 110.

I went from 235/75 r15 to 265/75 r16.

That's close enough to 10% change in rolling diameter so the GPS is right. You're overgeared by 10%.

Mine's no better as the tyres are similar to 265/75/16 so the tacho in mine used to show in 5th gear 3grand @ 115km/hr, 2750~2800 @100km/hr.

[Alex86]

I wouldnt be too concerned with an over-reading speedo- if you stick to the limit as displayed on the speedo, then your not really going to get fined for speeding.

GPS does have errors. Lower end models have greater error. The error could be more than the length of your car, so what this does to your speed can be quite drastic.
However a few metres when your lost and trying to direct a rescue crew to you aint so bad!!!!!!!!!!!

[Yonnee]

I was about to post the same question myself. My situation is the other way around, reads, 100 on the Speedo, but the gps says I?m doing 110.

I went from 235/75 r15 to 265/75 r16.

I remember reading on the old forums that there was a Speedo gear that you could buy from Mitsubishi, with reference to this site..... http://www.mitsu4wdclubqld.org/tips/tech/tech9611.htm

You just had to work out how many teeth you needed.

But as to where you actually put the gear, I?m not sure.

But i'm sure someone will be able to help us out.

Shane

I did this same thing to fix my own speedo error when I changed from 235/75R15's to 31x10.5 R 15's. At the end of your speedo cable where it connects to the gearbox/transmission there is a fitting. This fitting has a threaded section that your speedo cable screws to. This fitting also has four notches which are located by a lock which is bolted to the gearbox. Also on this fitting are a set of numbers, and a mark on the gearbox casing. These numbers correspond with the amount of teeth on the speedo drive.

To change the speedo drive gear, unscrew the speedo cable from the fitting. Remove the bolt holding the lock onto the fitting. The fitting should now just pull out of the gearbox, a slight twisting action might help here, and if the o-ring seal is still any good, it should still be a firm fit. Now with the fitting out, you'll see the gear cog you need to replace, and that it's held in place by a small pin, which you need to remove to swap the gear.

Installation is the reversal of removal.

Hope this helps.

Yonnee.

[Keeno]

How accurate is the GPS??
We have a PDA with GPS and I would not rely on it at all, despite what "everyone" says. Our unit records up to 8 metres or so movement even when the vehicle is off and stationary.

Yeah I know of the inaccuracies of gps units but as I was driving through some roadworks my speed was displayed at different times and these indications matched the gps not the vehicle speedo.

[Keeno]

That's 5% bigger than the 235/75/15 cheese cutters it was designed for.



That's close enough to 10% change in rolling diameter so the GPS is right. You're overgeared by 10%.

Mine's no better as the tyres are similar to 265/75/16 so the tacho in mine used to show in 5th gear 3grand @ 115km/hr, 2750~2800 @100km/hr.

The 265/70 R15 is the standard and only size for for my pajero.

At 100 kph in 5th gear the tacho reads approx. 2800 and at 110 kph the tacho reads a tad over 3000. What diff ratio are you running?

[Keeno]

I wouldnt be too concerned with an over-reading speedo- if you stick to the limit as displayed on the speedo, then your not really going to get fined for speeding.

GPS does have errors. Lower end models have greater error. The error could be more than the length of your car, so what this does to your speed can be quite drastic.
However a few metres when your lost and trying to direct a rescue crew to you aint so bad!!!!!!!!!!!

I rarely speed so being booked is not a fear I lose sleep over however it would appear at 100 kph on my speedo I'm doing more like 90 kph. Traveling at 90 kph on my usual roads isn't a problem but traveling on a motorway or similar it can become hazardous with other vehicles.

[Jaydee]

The 265/70 R15 is the standard and only size for for my pajero.

At 100 kph in 5th gear the tacho reads approx. 2800 and at 110 kph the tacho reads a tad over 3000. What diff ratio are you running?

Mine only states the 235/75/15 as the ones applicable and I've got the 31x10.5 about 40% worn on the 15" alloy mutli spoke GLS rims.

I never bothered to check actual gear ratios.... was more a casual observation I seemed to catch up to traffic.

[breadman]

When my speedo says I'm doing 100, My GPS says I'm doing 95, I'm happy with that, I know if I set the cruise control on 100, I won't be buying compulsory tickets to the policemans ball, Although my 2.8TD gets 9.5L per 100 k's on the highway

[Mad Mac]

That?s exactly what I was looking for thanks.

I'm one of those people that likes to have the time set to the actual time, not 5 mins fast, so you arrive early. And that carries over with the Speedo, I want a precise reading.

So where is this speedo cable located? Do i look up at the gearbox, from underneath the car, or does it connect on the top from inside, like where the gear stick is?

Cheers
Shane

I did this same thing to fix my own speedo error when I changed from 235/75R15's to 31x10.5 R 15's. At the end of your speedo cable where it connects to the gearbox/transmission there is a fitting. This fitting has a threaded section that your speedo cable screws to. This fitting also has four notches which are located by a lock which is bolted to the gearbox. Also on this fitting are a set of numbers, and a mark on the gearbox casing. These numbers correspond with the amount of teeth on the speedo drive.

To change the speedo drive gear, unscrew the speedo cable from the fitting. Remove the bolt holding the lock onto the fitting. The fitting should now just pull out of the gearbox, a slight twisting action might help here, and if the o-ring seal is still any good, it should still be a firm fit. Now with the fitting out, you'll see the gear cog you need to replace, and that it's held in place by a small pin, which you need to remove to swap the gear.

Installation is the reversal of removal.

Hope this helps.

Yonnee.

[Ranger J]

That?s exactly what I was looking for thanks.

I'm one of those people that likes to have the time set to the actual time, not 5 mins fast, so you arrive early. And that carries over with the Speedo, I want a precise reading.

So where is this speedo cable located? Do i look up at the gearbox, from underneath the car, or does it connect on the top from inside, like where the gear stick is?

Cheers
Shane

When you learn how the correct this Shane I will have to get you to show me when I fit the 285's.

Cheers,
Jayden

[Yonnee]

That?s exactly what I was looking for thanks.

No worries, anytime.

So where is this speedo cable located? Do i look up at the gearbox, from underneath the car,...

Yes...
If you climb under the passenger's side of the vehicle, you should see the speedo cable run down along the gearbox to the extension housing at the rear of the box. There'll be a knurled nut that screws the cable to the 'fitting'.

Yonnee.

[Easykill1978]

I really woudnt worry about this.. it most cases the speedo is out in a linear fasion. so in otherwords say at 110kph you are say in reality doing 103kph and say at 50 you could be doing 45.. it is near impossible to get n accurate speed. for example when you put different size tires or rims on, it changes the speedo.. the cable wears down a bit, not set 100% correctly at the factory.. as the tire wares down the speed goes more out of wack..

it doesnt bother me, as i have a navman.. reach speed and engage my cruise controll and i am off.. monitor my speed at all times.. no biggi

my cruise control cost me 268 (diy install).. nifty this., magnet attached to drive shaft, sensor on body..actuator on throttle and volla.. sense when u slow down and accelarates for you on hills and slows you on down hills

Thanks

Easy