Speedo accuracy

[Drew Advanced Member Find all posts View Profile Close Drew]

I'm amazed at the speedo in our new Prado.

Every other modern vehicle I've owned since I bought a GPS back in '99 has shown to have a speedo error of about 2~4%, I always figured it was so the manufacturers gave themselves a margin to prevent people from claiming they got a speeding ticket even though the stock speedo said they were not speeding.

My Prado reads SPOT ON! :shock: When compared to either of my 2 GPS units, the indicataed speed equals the satellite derived speed.

No longer can I afford to do 110km/h on the gauge knowing that it's only about 105km/h and thinking the cops won't bother to pull me over, 110km/h in a 100km/h zone, they will most likely pull me up.

Has anyone else notice this with their speedos?

Cheers,

Drew.

[johna Member Find all posts View Profile Close johna]

Speedo in mine (2003) reads 100 and GPS reads 100-101
With the standard tyres on vehicle.

John

[TEPUI Junior Member Find all posts View Profile Close TEPUI]

In my 90 series, the speedo and the GPS are always an exact match. (stock tires)

[Guest Close Guest]

When I had my factory tyres on it was 100% spot on to the GPS. Now I have fitted BF Goodrich All Terrains (my choice) it has thrown the speedo out. Now when I am travelling 110 kmh on the speedo, in fact I am doing 115 kmh.

Only downside to fitting tyres with a different profile. Whatever the incovenience this causes is far out weighed by the off road capabilities of these tyres.

[John Member Find all posts View Profile Close John]

My speedo underreads by 1-3 km/h according to my GPS.

Bearing in mind however that no GPS is 100% accurate, I take it with a grain of salt.

[Guest Close Guest]

BF Goodrich All Terrains

When I had my factory tyres on it was 100% spot on to the GPS. Now I have fitted BF Goodrich All Terrains (my choice) it has thrown the speedo out. Now when I am travelling 110 kmh on the speedo, in fact I am doing 115 kmh.

Only downside to fitting tyres with a different profile. Whatever the incovenience this causes is far out weighed by the off road capabilities of these tyres.

WA 1968, can you tell me about the BFGs? I've just bought a 120 series GX, I live in the WA desert and am wondering if the BFG ATs are worth the cashish... Does anything else work in size 17?

Cheers, Gordon.

[jeff s Avid PP Poster! Find all posts View Profile Close jeff s]

Hi Drew.

On the recent WA meetup to seabird we had an in convoy speedo test.
I have the cooper st in 265/70/17 and my gps was maybe 1 to 2 K under dash speedo reading. Almost identical, but that with about 30,000k of wear.

Chippy on the other hand was reading about 6 to 7K's slower than mine if I remember correctly at the same speed . Justo and leachy were there also so we had at least one with standard rubber.
We were on cruise and staying pretty close.

When the tyres were new it was a little worse, I did a speed refrence back then and it is posted here somewhere.


And wildmangordo, The coopers discoverer ST's are prety good in 17" and there are plenty of bridgies out there too.


Jeff.

[Jacto Senior Member Find all posts View Profile Close Jacto]

My speedo consistently reads 5km/hour more than what 2 GPS's running side by side for comparison show so at 100km/h on the speedo the 2 GPS units are reading 95km/h.

Vehicle is current model D4D and I was told by Toyota that this is normal and that speedo is not allowed to read the other way around (doing say 100 on the speedo and actual is 105)

Gives me some leeway for when I fit bigger tyres at changeout time.

[cuda Advanced Member Find all posts View Profile Close cuda]

2009 Speedo accuracy

Just noticed that with the 265/70/R17 tyres the speedo on the new Prado is almost accurate in comparison to my GPS. Has anyone else noticed this? I'm wondering whether Toyota has done this based on 2 things, safety (people drive slower thinking they are going faster :evil: )or they know most people put bigger tyres on these beasts.

Doug


Edit: Topic merged, please use search button to find relevent threads before starting new ones. - Mod

[D4D Addicted PP Member Find all posts View Profile Close D4D]

Re: 2009 Speedo accuracy

Yes, this has been covered before in numerous threads

[muscato Lurker Find all posts View Profile Close muscato]

Re: Speedo accuracy

My speedo reads 110 and my gps shows 108 so its not that bad.

[AJ120 Out of control poster! Find all posts View Profile Close AJ120]

Re: Speedo accuracy

My 2005 prado read spot on with the standard tyres and therefore read slow when i on the BFG's. My current 2009 Prado was reading fast with the standard tyres but now with the BFG's is reading spot on. I have been told on several occasions that the speedo in all knew cars must read fast, ie you are going slower than what the speedo reads.

Cheers Andrew

[Bushbasher Out of control poster! Find all posts View Profile Close Bushbasher]

Re: Speedo accuracy

ADRs require the speedo must not read any slower than true speed but they can be as much as 10% faster than true speed and they don't have to be any more accurate than that.

[StormyKnight Advanced Member Find all posts View Profile Close StormyKnight]

Re: Speedo accuracy

90 series standard tyres Cooper ST (265/70R16) GPS 100 speedo 103
265/75R16 BFG MT GPS 100 speedo 99

Nissan pathfinder...(work car!) GPS 111 speedo 119


The biggest issue I have with this inaccuracy is that speed limited trucks are limited to 100 'real' km/h.....If anyone is sitting on 100km/h or little below according to their speedo, they could easily be only doing a 'real' 90km/h. Any truck behind them & overtaking them they will claim is speeding!

PS overeading speedo's are great for fuel economy too!

Thank heavens for GPS's!

Cheers

[sparksy Senior Member Find all posts View Profile Close sparksy]

Re: Speedo accuracy

ADRs require the speedo must not read any slower than true speed but they can be as much as 10% faster than true speed and they don't have to be any more accurate than that.

My Mazda BT50 is out by exactly 10%. At 110K's on speedo you are actually doing 100k's. Tried to get Mazda to fix it under warranty but the replied all mazdas are like that and mazda wont allow the dealers to hook up the computer and correct it.
Didnt realise it until bought a new GPS and noted the difference, no wonder others were passing me.