Incorrect speed readout?

Majestik · 09-08-2009, 05:28 AM

Hi guys. I noticed a strange thing today. I drove to Geelong with cruise set at 100km. The whole way there I was wondering why everyone was passing me (even with cameras about). On the way back, the road had that thing that tell you the speed you're travelling. My cruise was still set at 100km but the speed sign thing said 92!
I know that there would be some descrepancy, but 8kmph??
It's maybe cause I've never bothered keeping to the speed limit that I've never noticed, but is this normal?
(If I could put fixed speed/red camera POPs in the nav I wouldn't have to worry)....

GTRFAN · 09-08-2009, 05:44 AM

My Navman has a realtime speed readout, so I'll do a test and let you know how mine compares. Pity the built in Nav doesn't show speed.

Mr Ed · 09-08-2009, 06:34 AM

I have had the same experience too with my Z. I noticed when I was doing the speed limit everyone was going past me.

During the 1000km service, I notified them my speedo was out of wack.

They tested it and it was under stated by 5%.

Nissan will do squat unless it is + / - 10%

I have a Navman that provides speed, note that it is not 100% accurate either.

But on my FPV GT - when I am doing 60kms, Navman shows 58km, 100km, Navman shows 98km.

In my Z - when I am doing 60, it shows 55, 100, it shows 94/95.

Therefore in the Z, I do the following speeds

65km for 60 zone
75km for 70 zone
110km for 100 zone.

If you take 5% off, you are in the safe zone.

Then again, in QLD you are given a 10% tolerence. I dont know for other states though,

Its a pain in the ***, but it aint the end of the world.

Also I heard that in some other forums, there is a conspiracy for motor companies to understate the speed - you do more kms than in reality. Which means warranty period according to mileage comes quicker. But you cant prove it.

evse82 · 09-08-2009, 06:46 AM

Yeah this is normal dude, mos acrs will be this far out, my 350z was the same too. I prefer it this way too because that one time you pass a camera and arent paying attention to the speedo (at 105 for instance) you'll get clocked at 97 or something so you won't get a fine.

jekel · 09-08-2009, 08:07 AM

yep mines same.....ppl always passing if i drive on the speedo indicator of 60 etc, usually drive 5km over and seems about right.

Majestik · 09-08-2009, 08:42 AM

Thanks guys! Great advise and opinions

I feel better now...
I did bloody 370km today in my new job role!!??

rudi · 09-08-2009, 07:13 PM

I have the same issue. See my earlier thread.

How accurate is your speedometer

evse82 · 09-08-2009, 07:59 PM

Quote:

Originally Posted by Majestik

Thanks guys! Great advise and opinions

I feel better now...
I did bloody 370km today in my new job role!!??

What are you doing now??

Majestik · 09-10-2009, 08:17 AM

Quote:

Originally Posted by evse82

What are you doing now??

Regional for Foxtel. Western suburbs mainly. Bloody doing 500+KM per week??
You want me to rack up some kms in your car for ya?

09-08-2009, 05:28 AM	#1 (permalink)
Majestik Track Member Join Date: Aug 2009 Location: SE Melbourne, Australia Posts: 800 Drives: '13 Jet Black R35GTR Rep Power: 16	Incorrect speed readout? Hi guys. I noticed a strange thing today. I drove to Geelong with cruise set at 100km. The whole way there I was wondering why everyone was passing me (even with cameras about). On the way back, the road had that thing that tell you the speed you're travelling. My cruise was still set at 100km but the speed sign thing said 92! I know that there would be some descrepancy, but 8kmph?? It's maybe cause I've never bothered keeping to the speed limit that I've never noticed, but is this normal? (If I could put fixed speed/red camera POPs in the nav I wouldn't have to worry)....

09-08-2009, 05:44 AM	#2 (permalink)
GTRFAN Track Member Join Date: Dec 2008 Location: Melbourne Posts: 586 Drives: 370z Titanium 6MT Rep Power: 17	My Navman has a realtime speed readout, so I'll do a test and let you know how mine compares. Pity the built in Nav doesn't show speed. __________________ My Zed

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09-08-2009, 06:34 AM	#3 (permalink)
Mr Ed Base Member Join Date: Aug 2009 Location: Brisbane, Australia Posts: 162 Drives: 09 Nissan 370Z M6 Rep Power: 15	I have had the same experience too with my Z. I noticed when I was doing the speed limit everyone was going past me. During the 1000km service, I notified them my speedo was out of wack. They tested it and it was under stated by 5%. Nissan will do squat unless it is + / - 10% I have a Navman that provides speed, note that it is not 100% accurate either. But on my FPV GT - when I am doing 60kms, Navman shows 58km, 100km, Navman shows 98km. In my Z - when I am doing 60, it shows 55, 100, it shows 94/95. Therefore in the Z, I do the following speeds 65km for 60 zone 75km for 70 zone 110km for 100 zone. If you take 5% off, you are in the safe zone. Then again, in QLD you are given a 10% tolerence. I dont know for other states though, Its a pain in the ***, but it aint the end of the world. Also I heard that in some other forums, there is a conspiracy for motor companies to understate the speed - you do more kms than in reality. Which means warranty period according to mileage comes quicker. But you cant prove it.

09-08-2009, 06:46 AM	#4 (permalink)
evse82 Track Member Join Date: Nov 2008 Location: Melbourne, AUS Posts: 609 Drives: Black 370z MT Rep Power: 17	Yeah this is normal dude, mos acrs will be this far out, my 350z was the same too. I prefer it this way too because that one time you pass a camera and arent paying attention to the speedo (at 105 for instance) you'll get clocked at 97 or something so you won't get a fine.

09-08-2009, 08:07 AM	#5 (permalink)
jekel Base Member Join Date: Apr 2009 Location: Australia Posts: 170 Drives: Pearl White 6MT Rep Power: 16	yep mines same.....ppl always passing if i drive on the speedo indicator of 60 etc, usually drive 5km over and seems about right.

09-08-2009, 08:42 AM	#6 (permalink)
Majestik Track Member Join Date: Aug 2009 Location: SE Melbourne, Australia Posts: 800 Drives: '13 Jet Black R35GTR Rep Power: 16	Thanks guys! Great advise and opinions I feel better now... I did bloody 370km today in my new job role!!??

09-08-2009, 07:13 PM	#7 (permalink)
rudi Enthusiast Member Join Date: Jun 2009 Location: Australia Posts: 306 Drives: 370Z Australian Spec Rep Power: 15	I have the same issue. See my earlier thread. How accurate is your speedometer