MPH: IPK not match speedo dial

Wayne2015 · 25th July 2015, 11:00

My speed on IPK matches the satnav speed but neither matches the speedo dial

Any reason why?
Does the IPK also uses GPS???

KWIL · 25th July 2015, 11:16

Speedometer dial is required by law to be optimistic, that way if you stick to the speed limit as shown on the dial, you will not breaking the law

Mike Noc · 25th July 2015, 11:37

It has been mentioned on the forum that on the V8 models where this was standard fit they do agree, so the readout must be able to be tweaked somewhere in the software.

Dorset Bob · 25th July 2015, 11:38

Same here, I have found that the digital speed readout is more accurate, but still over-reads (although less than the analogue speedo).

As I understand it, the digital speed information collects data from the pulses from the ABS, at the wheel, without modification, as does the odometer.
I have also noted that when you tripping a distance it isn't 10% out, like the analogue speedo.

There seems to be software that deliberately makes the analogue speedo. over-read.

coab · 25th July 2015, 12:16

On my last car the difference between the ipk speed and the speedo was very little. As stated the speedo is always a little behind but mine was only about 2 mph at 60 mph.

klarzy · 25th July 2015, 13:05

as I understand it the actual speed and trip distance are taken with a fair degree of accuracy (dependent on tyre size and wear etc...) from the ABS sensor signal on the front drivers side wheel. this is displayed directly to the digital speedo and trip / ODO for accuracy. there is then an internal calculation (which I think can be "Tuned" to give a 4-7% overspeed indication to the speedo needle.

This is to protect the OEM's from claims of speeding tickets being the fault of the car due to inaccuracy of the speedo... if you are clocked at 75 then you must have been showing at least 80 on the needle and it is therefor your fault, no argument...

Wayne2015 · 25th July 2015, 13:08

Ah
Cool guys - thanks

I was thinking maybe my car had factory Satnav and the same GPS receiver was link to the IPK as both speed readouts matches exactly the same!

murphyv310 · 25th July 2015, 14:13

Hi.
As far as I'm aware GPS speed displays are only accurate on a straight and level road.
Somehow the "Road Angel" devices are able to compensate for this.

25th July 2015, 11:00	#1
Wayne2015 Loves to post Mk1 MG ZT V6 (auto) Join Date: May 2015 Location: Windy Yorkshire! Posts: 401 Thanks: 109 Thanked 27 Times in 22 Posts	MPH: IPK not match speedo dial My speed on IPK matches the satnav speed but neither matches the speedo dial Any reason why? Does the IPK also uses GPS???

25th July 2015, 11:38	#4
Dorset Bob Senior Citizen Rover 75 2.5 Connoisseur SE,Chrysler 300C,124 Spider, Daytona 955i,Honda XL250 & Royal Enfield 650GT Join Date: Feb 2008 Location: The Kingdom of Wessex Posts: 6,976 Thanks: 2,391 Thanked 2,685 Times in 1,686 Posts	Same here, I have found that the digital speed readout is more accurate, but still over-reads (although less than the analogue speedo). As I understand it, the digital speed information collects data from the pulses from the ABS, at the wheel, without modification, as does the odometer. I have also noted that when you tripping a distance it isn't 10% out, like the analogue speedo. There seems to be software that deliberately makes the analogue speedo. over-read. __________________ Let the good times roll............

25th July 2015, 13:05	#6
klarzy This is my second home none but not gone Join Date: Mar 2013 Location: March, Cambs Posts: 16,437 Thanks: 894 Thanked 4,247 Times in 3,025 Posts	as I understand it the actual speed and trip distance are taken with a fair degree of accuracy (dependent on tyre size and wear etc...) from the ABS sensor signal on the front drivers side wheel. this is displayed directly to the digital speedo and trip / ODO for accuracy. there is then an internal calculation (which I think can be "Tuned" to give a 4-7% overspeed indication to the speedo needle. This is to protect the OEM's from claims of speeding tickets being the fault of the car due to inaccuracy of the speedo... if you are clocked at 75 then you must have been showing at least 80 on the needle and it is therefor your fault, no argument... __________________ [SIGPIC][/SIGPIC]….All praise Bananaswan….

25th July 2015, 14:13	#8
murphyv310 This is my second home Hyundai i10 998cc Join Date: Mar 2012 Location: Kilmarnock Posts: 6,602 Thanks: 2,088 Thanked 2,298 Times in 1,349 Posts	Hi. As far as I'm aware GPS speed displays are only accurate on a straight and level road. Somehow the "Road Angel" devices are able to compensate for this. __________________ Cheers from Trevor MM0KJJ

25th July 2015, 11:16	#2
KWIL Precise Rover 75 Tourer 2.5KV6 Connoisseur SE Join Date: Mar 2013 Location: Fleet Posts: 2,954 Thanks: 630 Thanked 617 Times in 480 Posts	Speedometer dial is required by law to be optimistic, that way if you stick to the speed limit as shown on the dial, you will not breaking the law

25th July 2015, 11:37	#3
Mike Noc This is my second home Rover 75 CDT Manual Connoisseur SE, Rover 75 CDT Automatic Connoisseur SE & a Freelander Td4. Join Date: Jul 2009 Location: Hampshire Posts: 11,550 Thanks: 3,470 Thanked 3,119 Times in 2,247 Posts	It has been mentioned on the forum that on the V8 models where this was standard fit they do agree, so the readout must be able to be tweaked somewhere in the software.

25th July 2015, 12:16	#5
coab This is my second home 2007 57 GOLF GTi EDITION 30 DSG Join Date: Nov 2011 Location: Newport Shropshire and Coventry. Posts: 5,138 Thanks: 2,424 Thanked 1,452 Times in 852 Posts	On my last car the difference between the ipk speed and the speedo was very little. As stated the speedo is always a little behind but mine was only about 2 mph at 60 mph.

25th July 2015, 13:08	#7
Wayne2015 Loves to post Mk1 MG ZT V6 (auto) Join Date: May 2015 Location: Windy Yorkshire! Posts: 401 Thanks: 109 Thanked 27 Times in 22 Posts	Ah Cool guys - thanks I was thinking maybe my car had factory Satnav and the same GPS receiver was link to the IPK as both speed readouts matches exactly the same!