Diff ratio tyre size speedo gear (pinion)

Here's a list of pinions to suit tyre sizes with accompanying diff ratios to get your speedo within specs. It worked for me for engineers. Got my speedo within 4% which is NSW law. cost from Nissan at the time $74. Or you can pay $220 for a Tyre match box. Cheers Jono.

Diff ratio Tyre size Speedo gear (pinion)
Part Number i.e. 4.11:1 ratio running 31” tyres 32703 - 31G 17 Change last 2 digits for gear you need.

3.9:1 Ratio
Tyre Pinion
31 16
33 15
35 14
37 13

4.11:1 Ratio
31 17
33 16
35 15
37 14

4.375:1 Ratio
31 18
33 17
35 16
37 15

4.625:1 Ratio
31 19
33 18
35 17
37 16

well done cheers mate helps to sort out the dark art of speedo v tyres v ratios

Top find and post mate!!! Well done and thanks!!

Great Post mate, im sure will help out a few members at some point

This will come in handy, that's for sure.


Sent from the secret chambers of our secret society, on a secret iPhone, with a secret pin code and eye retina scanning from a secret peep hole, just don't tell anyone OK, cos it's secret........

Top marks TD42

Last time i got some gears from nissan. not many in stock in australia. not sure if their is after market parts.

Thanks mate, an unexpected help for a problem I thought I'd have to just 'follow the traffic' for!

You can adjust the GQ's speedo

There is a trim pot on the dash pcb - I have posted details elsewhere

how good are you, excellent home work, I have cross checked your post and you are 100% correct with your ratio verses pinion drive gear again WELL DONE

Hi everyone.
Thanks for all the info provided about speedo correction and pinion gear tooth numbers.
My 1990 Maverick (TD42) has had an incorrect speedo pinion gear fitted in the transfer case since I purchased the vehicle 3 years ago. The gear fitted had 19 teeth and with my 265/75/r16 (31.6”) tyres, the speedo reads around 15% below the actual road speed.
To correct for this (and in preparation for slightly larger 33” tyres), I purchased a 16 tooth gear based on the advice provided above and other patrol forums. The part I ordered was 32703-31G16, and cost about $85 from my local Nissan dealer.
At first glance, the part looked like an exact replacement with 16 teeth as required. Unfortunately, the diameter of the plastic gear was significantly smaller than the former 19 tooth gear. I installed the new 16 tooth gear, hoping that the gear in the transfer box might be spring loaded to take up the difference in size, but the spindle spins freely by hand once installed and therefore did not operate the speedo at all when test driven.
Does anyone know if I’ve ordered the wrong part number for my needs? How can I find the correct part number?

Thanks i am having speedo problems this will help. :thumbup: