Speedo problems

[JoshA]

Just got my D40 and its reading 6kmh higher than it should be, and I am just using my Sat Nav to confirm the readings. WHen I wear out the tyres that it came with I will probably go with some higher profile tyres.

anybody have any suggestions as to how wide and how tall you can go on standard wheels??

[navarian]

I run 265/75/16 on mine.My speedo ran about 4 kmh higher,now 1kmh slower.
You might not want to go bigger in tires than this size on a standard rim or you could get rubbing on the inner guards or the front plastic bit under the bumper,if you have one.

[Old.Tony]

My speedo ran about 4 kmh higher,now 1kmh slower.

Don't forget that in order to remain roadworthy, your speedo must NEVER indicate a speed lower than it is travelling. It is allowed to indicate up to 10% over, but it is a zero tolerance for under reading.

That being said of course, they may never inspect it. It may only ever become an issue during a roadworthiness inspection, or accident investigation.

[bullwinkle]

Speedo problems are common right across the whole spectrum of registered vehicles in Australia. At highway speeds I usually drive at an indicated 5km greater than the posted limit in the Navara. My wife's 2007 Ford Territory also has a speedo which is about 4km/hr under.

[Bosshog]

Originally Posted by Old.Tony

Don't forget that in order to remain roadworthy, your speedo must NEVER indicate a speed lower than it is travelling. It is allowed to indicate up to 10% over, but it is a zero tolerance for under reading.

That being said of course, they may never inspect it. It may only ever become an issue during a roadworthiness inspection, or accident investigation.

I have spent far too much time on getting 265/75s certified for my D40. Anyway, Tony's not too far off the mark. ADR18/03 changed on 1 July 2006. All vehicles made after that date CANNOT indicate a lower speed than is actually being travelled. Furthermore, there is now NO upper limit on how much faster a speedo can read. As a result to ensure compliance vehicle manufacturers' default to around an average of 14% higher (so the engineer tells me). We're lucky with just 10% error, Hilux's are closer to 14% I gather.

Anyway I have to get my Speedo checked and recalibrated and the engineer 'has to observe' the tyres actually being fitted to the vehicle. What a load of rubbish to fit tyres that should have been standard fitment.

[navarian]

So if my vehicle was made in September 2005 and i run a different tyre size than the vehicle was made with and my speedo reads a couple of kmh's slower it is still roadworthy?Or would that only apply for a vehicle made then with the factory tyre size.

[Old.Tony]

Guys, if you're recalibrating your speedo, don't forget that it may be possible to use that kit from Jaycar, it's a plug-in on-the-fly-adjustable calibration tool for electronic speedos.

It's been mentioned in these forums before, can't remember where, I'll find the thing on Jaycar's site again: here is a direct link to the part in their Kits - Automotive section.

[Bosshog]

Originally Posted by Old.Tony

Guys, if you're recalibrating your speedo, don't forget that it may be possible to use that kit from Jaycar, it's a plug-in on-the-fly-adjustable calibration tool for electronic speedos.

It's been mentioned in these forums before, can't remember where, I'll find the thing on Jaycar's site again: here is a direct link to the part in their Kits - Automotive section.

Thanks Tony, however at $55 I'll pay another $15 to get an 'expert' to check and calibrate the speedo as they quoted me $70 for the job.

[Bosshog]

Originally Posted by navarian

So if my vehicle was made in September 2005 and i run a different tyre size than the vehicle was made with and my speedo reads a couple of kmh's slower it is still roadworthy?Or would that only apply for a vehicle made then with the factory tyre size.

Navarian, I'll my new best friend - the engineer and then you'll have the experts answer rather than my opinion.

[Nomadic Navara]

Originally Posted by Bosshog

All vehicles made after that date CANNOT indicate a lower speed than is actually being travelled. Furthermore, there is now NO upper limit on how much faster a speedo can read.

This is not correct. Go back to the link I posted in message 3 and see the correct limits specified in the ADR.

PeterD