speed accuracy?

[TTTTTT]

Hi Guys,
Picked up my first LRDS on the weekend. L550 with black pack (inc 20 inch rims). Anyway, noticed the speedo is telling me speed is approximately 7-8km/hr higher than my ever trusty GPS. I'd believe the GPS because if I sit on the speed limit I am left behind by the traffic (and no, we aren't all leadfoots on Queensland roads).

According to the calculator there should only be a 1% difference between say the 17 inch rims and 20's. Coming from a long line of Toyotas (boring but accurate), I was wondering if this is an idiosyncracy know to LR owners, or something I need to address with the dealer?

Would appreciate some feedback.

Thanks on my first post.

[DiscoMick]

Believe the GPS. Speedos must always read higher than the actual speed by law.

Sent from my SM-G900I using AULRO mobile app

[scarry]

Our Toyota vans generally show speed on dash around 5 % higher than actual.

[TTTTTT]

Thanks Guys,
Think i'll run it by the dealer and see if anything can be done.

[Romeo]

Fossicker,
Did you get any joy from the dealer?
My new DS MY17 reads 64 when the GPS tells me 60. My understanding of the ADR is that the speedo is not allowed to read low, but must read no more than 10% high. My previous car (Audi) read 101 at 100kph and proportional at lower speed, so accuracy is possible.
The other interesting thing is that, according to the manual, Lane Departure Warning is active above 60kph. In my car it activates when the speedo says - you guessed it - 64kph. Coincidence? Don't know. Has anyone else seen this?
Roman

[BobD]

Fossicker,
Did you get any joy from the dealer?
My new DS MY17 reads 64 when the GPS tells me 60. My understanding of the ADR is that the speedo is not allowed to read low, but must read no more than 10% high. My previous car (Audi) read 101 at 100kph and proportional at lower speed, so accuracy is possible.
The other interesting thing is that, according to the manual, Lane Departure Warning is active above 60kph. In my car it activates when the speedo says - you guessed it - 64kph. Coincidence? Don't know. Has anyone else seen this?
Roman


That is correct. The car knows the correct speed and distance and the settings in the configuration file increases the displayed speed by a certain amount, which can be adjusted in the configuration. On the D4 it is 2kph + 3.5% from what I can gather. I don't know what it is for a DS yet.


On my ex VW Multivan the speed was even more optimistic than the DS but the DS seems to be pretty similar to the D4.

[coladuna]

I wouldn't worry. I have never owned a car that showed accurate speedo reading. It was always off by upto 10% higher than the actual speed you are doing.

[Romeo]

Bob

"...The car knows the correct speed and distance and the settings in the configuration file increases the displayed speed by a certain amount, which can be adjusted in the configuration..."

I'm new to this. Where can I found out more about this "configuration file" and can I/how do I see it or tweak it?

I'm unashamedly one of those people who don't appreciate big brother pretending I'm going faster than I am - I have a wife for that. Give me the info and let ME deal with it, not some *** who thinks he knows better:)

Roman

[BobD]

As far as I know we can't access the CCF yet as no one has made a diagnostic tool for the DS. I assume that the GAP IID BT tool will read it in the future as it does for most other Land Rover products, including the Evoque and the Freelander. When it does, you will be able to adjust the CCF as you can on the D4, for example. I will then add it to my existing D4 license for the tool.

[DiscoMick]

Bob

"...The car knows the correct speed and distance and the settings in the configuration file increases the displayed speed by a certain amount, which can be adjusted in the configuration..."

I'm new to this. Where can I found out more about this "configuration file" and can I/how do I see it or tweak it?

I'm unashamedly one of those people who don't appreciate big brother pretending I'm going faster than I am - I have a wife for that. Give me the info and let ME deal with it, not some *** who thinks he knows better:)

Roman
It's the law, so be careful you don't fiddle and make your vehicle unroadworthy.

[willem]

I'm just wondering how to display the GPS speed. I can't find it.

2016 Disco Sport HSE TD4.

[BobD]

That's because you can't look at it.

When they set up the Gap IID for the DS you will be able to use it to look at the real speed, which as I said, is known by the car and adjusted up before being displayed, to meet the legal speedo requirements.

[willem]

That's because you can't look at it.

When they set up the Gap IID for the DS you will be able to use it to look at the real speed, which as I said, is known by the car and adjusted up before being displayed, to meet the legal speedo requirements.

Well, that makes sense! :( The car can tell you the actual speed, but 'legal requirements' won't let the car tell you the actual speed. So you have to sit there and do little sums in your head to work out the speed you are actually doing.

Who thought this one up?

[BobD]

I suspect that all modern cars do the same sort of thing. It is the same in the 2010 D4 and is probably driven by ADR's or whatever other rules Land Rover has to comply with all over the world. Like you, I hate it and have to continually convert and set the cruise higher.

Certainly the same sort of speedo "error" on all recent cars of different brands that I have had. Others seem to have had more accurate speedos on some brands from their posts on the subject on the D4 forum.

If you can find a place where you can check distances (WA has km pegs every 2 km on major roads) you can check the odometer accuracy and you will find it is almost perfect because both distance and speed are calculated accurately by the ECU.

With the GAP IID on my D4 you can display the actual speed as it is a parameter that the ECU's generate. The only trouble is that my bigger tyres mean that the displayed speed is accurate and the Odo is out, so there is no point looking at the now wrongly calculated ECU speed!