Inaccurate Speedo - Page 3

briggie · 18-07-2010, 22:02

Quote:

Originally Posted by danielj

smaller tyres should correct it somewhat. Have a go at the tyre size calculator on the downloads section and see what size will get you reading the correct speed.

very very interesting ... i had a little play guessing tyre sizes ..... it makes a big difference doesnt it ? ..... will check the tyre size i have on now in the morning ( its too dark now lol )

lacroupade · 18-07-2010, 23:01

over-reading speedo is common as muck, most cars do it - combination of reasons but of course it also makes your fuel consumption look better than it really is.....

The Patrolman · 19-07-2010, 22:12

I have always been led to belive that speedo's ( not the I'll fitting swim wear!! ) are allowed to read upto 10%fast but nothing slow, so if you think your doing 110 MPH you could only be doing 99MPH, but would be doing no more than 110MPH.
Actually Unless you have a 4.2 Petrol Troll the quoted figures are only to be dreamed about!!! LOL!!!!!!!!

The Patrolman · 19-07-2010, 22:15

BUT your odometer has to read correctly!
So if your being Anal or Paranoid you could work out time travelled over distance covered to see if it all ads up!!
Or spend the time having a well deserved Tinn'y and not worry about it!!

larson · 25-07-2010, 22:14

i found this on another forum... i just had a quick brouse and then cut/paste it.

The CORRECT way to Calibrate your speedo

--------------------------------------------------------------------------------

Hello All

This will be of interest to anyone who has changed their tyres to non standard Diameter.

I changed my standard tyres to 275/70/17's and this caused the speedo to read under by 6%.

I investigated fitting an electronic switch to convert the signal but having had a Jeep before and changing tyres and gears a few times I wanted to correct the problem at the SOURCE and not the dash display.

After almost NINE months I finally found the part numbers and a big thanks go to Wayne at Blackburn Nissan 4x4 for getting this for me.

The standard pinion speedometer gear on a 3.0L GU Manual has 17 teeth and in my case my speedo is reading 6% below the actual speed.

So to calculate the correct gear:
Standard Gear = 17 Teeth
Speedo Error = 6% Below
6% of 17 = 1.02
Number of teeth Required = 16 (17-1)

Of course if your speedo is reading higher then the actual speed then you need to add teeth.

The following part numbers are needed to order the correct gear:

32743-VB015 15 Teeth
32743-VB016 16 Teeth
32743-74P17 17 Teeth
32743-74P18 18 Teeth
Cost approx $50.

Again - Thanks to Blackburn Nissan 4x4 for this information.

To install the gear:
I have documented the steps in a series of pictures below.

1) Locate the pinion speedo gear Housing - just next to the Handbrake Drum at the rear of the gearbox.

2) Using a 10mm socket - remove the screw on the side of the housing and
slowly pull the housing out. Warning - you will lose about a cup of gear oil
so place a bucket under the gear box. Dont worry - it will run out and stop
after about 10 seconds

3) Remove the old gear (Black in Picture)
The gear is held on by a C-Clip which uses tiny holes. I just used a
screw driver to remove it.

4) Put the new gear on the spindle (Yellow) and re-attach the C-Clip

5) Push the gear housing back into the gear box. It will need a slight tap to
reseat the O-Ring. And screw in the bolt (dont over tighten).

Took the car for a drive and it is reading almost 100% accurate with the GPS.

This is the best $50 I have spent on my car.

PS: In case you are wondering - I did top up the gear box oil.

Happy new year and regards

Marc
Attached Images Speedo Gear 1.JPG (32.1 KB, 690 views)
Speedo Gear 2.JPG (25.2 KB, 637 views)
Speedo Gear Origial.JPG (25.1 KB, 648 views)
Original Gear.JPG (23.8 KB, 650 views)
New Gear.JPG (21.2 KB, 624 views)
New Gear Fitted.JPG (27.0 KB, 614 views)

--------------------------------------------------------------------------------
Last edited by MarcusParcus; 08-01-2007 at 12:52 PM.

i hope it helps pathboy

briggie · 26-07-2010, 07:07

very very interesting patbhoy , thanks mate

lacroupade · 26-07-2010, 11:32

That sounds like a little job to slot in between pudding and a cuppa eh?

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

18-07-2010, 23:01	#32
lacroupade Senior Member Join Date: Jan 2009 Location: All hail to the Glove of Love... Posts: 9,212	over-reading speedo is common as muck, most cars do it - combination of reasons but of course it also makes your fuel consumption look better than it really is.....

19-07-2010, 22:12	#33
The Patrolman Senior Member Join Date: Nov 2009 Location: Redcar, Teesside Vehicle: Y60 Patrol 4.2 PeTroll Posts: 2,122	I have always been led to belive that speedo's ( not the I'll fitting swim wear!! ) are allowed to read upto 10%fast but nothing slow, so if you think your doing 110 MPH you could only be doing 99MPH, but would be doing no more than 110MPH. Actually Unless you have a 4.2 Petrol Troll the quoted figures are only to be dreamed about!!! LOL!!!!!!!!

19-07-2010, 22:15	#34
The Patrolman Senior Member Join Date: Nov 2009 Location: Redcar, Teesside Vehicle: Y60 Patrol 4.2 PeTroll Posts: 2,122	BUT your odometer has to read correctly! So if your being Anal or Paranoid you could work out time travelled over distance covered to see if it all ads up!! Or spend the time having a well deserved Tinn'y and not worry about it!!

25-07-2010, 22:14	#35
larson Senior Member Join Date: Jun 2009 Location: moomin vally Posts: 1,138	i found this on another forum... i just had a quick brouse and then cut/paste it. The CORRECT way to Calibrate your speedo -------------------------------------------------------------------------------- Hello All This will be of interest to anyone who has changed their tyres to non standard Diameter. I changed my standard tyres to 275/70/17's and this caused the speedo to read under by 6%. I investigated fitting an electronic switch to convert the signal but having had a Jeep before and changing tyres and gears a few times I wanted to correct the problem at the SOURCE and not the dash display. After almost NINE months I finally found the part numbers and a big thanks go to Wayne at Blackburn Nissan 4x4 for getting this for me. The standard pinion speedometer gear on a 3.0L GU Manual has 17 teeth and in my case my speedo is reading 6% below the actual speed. So to calculate the correct gear: Standard Gear = 17 Teeth Speedo Error = 6% Below 6% of 17 = 1.02 Number of teeth Required = 16 (17-1) Of course if your speedo is reading higher then the actual speed then you need to add teeth. The following part numbers are needed to order the correct gear: 32743-VB015 15 Teeth 32743-VB016 16 Teeth 32743-74P17 17 Teeth 32743-74P18 18 Teeth Cost approx $50. Again - Thanks to Blackburn Nissan 4x4 for this information. To install the gear: I have documented the steps in a series of pictures below. 1) Locate the pinion speedo gear Housing - just next to the Handbrake Drum at the rear of the gearbox. 2) Using a 10mm socket - remove the screw on the side of the housing and slowly pull the housing out. Warning - you will lose about a cup of gear oil so place a bucket under the gear box. Dont worry - it will run out and stop after about 10 seconds 3) Remove the old gear (Black in Picture) The gear is held on by a C-Clip which uses tiny holes. I just used a screw driver to remove it. 4) Put the new gear on the spindle (Yellow) and re-attach the C-Clip 5) Push the gear housing back into the gear box. It will need a slight tap to reseat the O-Ring. And screw in the bolt (dont over tighten). Took the car for a drive and it is reading almost 100% accurate with the GPS. This is the best $50 I have spent on my car. PS: In case you are wondering - I did top up the gear box oil. Happy new year and regards Marc Attached Images Speedo Gear 1.JPG (32.1 KB, 690 views) Speedo Gear 2.JPG (25.2 KB, 637 views) Speedo Gear Origial.JPG (25.1 KB, 648 views) Original Gear.JPG (23.8 KB, 650 views) New Gear.JPG (21.2 KB, 624 views) New Gear Fitted.JPG (27.0 KB, 614 views) -------------------------------------------------------------------------------- Last edited by MarcusParcus; 08-01-2007 at 12:52 PM. i hope it helps pathboy

26-07-2010, 07:07	#36
briggie Senior Member Join Date: Mar 2010 Location: peoples democratic republic of west yorkshire Vehicle: " alice " Posts: 10,473	very very interesting patbhoy , thanks mate

26-07-2010, 11:32	#37
lacroupade Senior Member Join Date: Jan 2009 Location: All hail to the Glove of Love... Posts: 9,212	That sounds like a little job to slot in between pudding and a cuppa eh?