UK Diesel Car NZ Mph / KmH RUC Question

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outdoorsnz

674 posts

Ultimate Geek

#319262 7-Apr-2025 11:13

I've just bought a 2nd hand diesel car that was privately imported (not a dealer) into NZ awhile ago.

Car is in MPH. So odometer / trip meter etc is also in miles. Does have Kmh on the inside of speedometer dial. Just ordered a cheap dash GPS speedo to avoid confusion and can see speed at a glance.

But I can't quite get my head around the diesel RUC in respects to odometer being in miles and can't see anything about this on NZTA.

So you buy RUC in K's. 1000 k units. Looking at al the past WOFs etc, it looks like they've possibly just treated the odometer like it is in K's. And the same for RUC.

What is the correct way to do this? Thanks

eracode

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#3361628 7-Apr-2025 12:36

Interesting question. FWIW ChatGPT says:

“In New Zealand, if your vehicle’s odometer is in miles, you still need to comply with Road User Charges (RUC) — but you must convert miles to kilometers, since RUC is based on kilometers traveled.

Here’s how to handle it:

1. Convert Miles to Kilometers

Use the standard conversion: 1 mile = 1.60934 kilometers
Example: if your odometer shows 10,000 miles, that’s 16,093.4 km for RUC purposes.

2. Recording Distance

When buying RUC, you’ll be asked to enter the current odometer reading. If your odometer is in miles:

Multiply it by 1.60934
Then round up to the nearest whole kilometer.

3. Display and Compliance

The distance license must still reflect kilometers.
Keep documentation showing the mileage-to-kilometers conversion (especially for COF/WOF checks or audits).

4. At Inspection

WOF or COF inspectors may note the odometer is in miles — it’s good to inform them upfront and clarify that your RUC purchases reflect converted to kilometres.”

Sometimes I just sit and think. Other times I just sit.

Aucklandjafa

380 posts

Ultimate Geek

#3361629 7-Apr-2025 12:37

I’d assume they’ve converted the mile count at the initial registration at import and then have carried that on - otherwise you may have found a great loophole to save 60% on RUCs!

As it stands now, if you convert the mileage to km, does it fall within the RUC usage period?

eracode

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#3361635 7-Apr-2025 12:40

I’d say it is in dangerous territory with RUC to treat the odo as if it’s in km when it’s actually miles. Obviously paying per 1,000km but enjoying 1,600km. Have no idea what the penalty would be if caught - and no idea what the chances are of getting caught. It could also end up affecting insurance cover in the event of a claim.

Edit: Resorting again to ChatGPT:

“In New Zealand, falsifying Road User Charges (RUC) records or providing false information is a serious offense under the Road User Charges Act 2012. The penalties for such actions are as follows:

Individuals: If an individual knowingly produces false records or information related to RUC, they are liable on conviction to a fine not exceeding $15,000.
Body Corporates (Companies): If a body corporate commits the same offense, it is liable on conviction to a fine not exceeding $75,000.

These penalties underscore the importance of accurately reporting RUC-related information. Ensuring compliance with RUC regulations helps maintain the integrity of New Zealand’s road funding system and avoids substantial fines.”

Sometimes I just sit and think. Other times I just sit.

wellygary

8266 posts

Uber Geek

#3361701 7-Apr-2025 13:38

The conversion factor of 1.6 km = 1 mile is a pretty universally known ratio, especially when someone is bringing a prosecution against you....

Did the RUC license match the ODO when you bought it? ( after converting to kms)

If so buy enough Kms to cover the distance you have travelled.

If the numbers don't match, and your RUC licenses= miles ODO, then you're going to have to sort it out with NZTA at some point...

if you're stopped and they notice the ODO is in miles and doesn't corelate with the correct RUC Kms, then it will be on you

Bung

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#3361704 7-Apr-2025 13:42

eracode:

Interesting question. FWIW ChatGPT says:

“In New Zealand, if your vehicle’s odometer is in miles, you still need to comply with Road User Charges (RUC) — but you must convert miles to kilometers, since RUC is based on kilometers traveled.

Here’s how to handle it:

1. Convert Miles to Kilometers

Use the standard conversion: 1 mile = 1.60934 kilometers
Example: if your odometer shows 10,000 miles, that’s 16,093.4 km for RUC purposes.

NZTA refer to 1000km being equivalent to 621 miles, I doubt they go to that many decimal places.

outdoorsnz

674 posts

Ultimate Geek

#3361709 7-Apr-2025 13:52

Thanks for all the reply's. Confirmed what I thought was correct.

eracode

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#3361714 7-Apr-2025 14:11

Bung:

eracode:

Interesting question. FWIW ChatGPT says:

“In New Zealand, if your vehicle’s odometer is in miles, you still need to comply with Road User Charges (RUC) — but you must convert miles to kilometers, since RUC is based on kilometers traveled.

Here’s how to handle it:

1. Convert Miles to Kilometers

Use the standard conversion: 1 mile = 1.60934 kilometers
Example: if your odometer shows 10,000 miles, that’s 16,093.4 km for RUC purposes.

NZTA refer to 1000km being equivalent to 621 miles, I doubt they go to that many decimal places.

ChatGPT isn’t that smart.

Sometimes I just sit and think. Other times I just sit.

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tweake

2349 posts

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#3361778 7-Apr-2025 17:02

outdoorsnz:

I've just bought a 2nd hand diesel car that was privately imported (not a dealer) into NZ awhile ago.

Car is in MPH. So odometer / trip meter etc is also in miles. Does have Kmh on the inside of speedometer dial. Just ordered a cheap dash GPS speedo to avoid confusion and can see speed at a glance.

But I can't quite get my head around the diesel RUC in respects to odometer being in miles and can't see anything about this on NZTA.

So you buy RUC in K's. 1000 k units. Looking at al the past WOFs etc, it looks like they've possibly just treated the odometer like it is in K's. And the same for RUC.

What is the correct way to do this? Thanks

the other option is to speak to a speedo repair place and see if they can flash the instrument cluster to the metric version.

Bung

6403 posts

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#3361790 7-Apr-2025 17:53

Our made in Hungary Suzuki gives you the choice of units for odometer and trip meters. You are stuck with the original choice of mph or kph as major and minor speedo labels. 1st find a manual 😁

eracode

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#3362480 9-Apr-2025 20:47

Bung:

Our made in Hungary Suzuki gives you the choice of units for odometer and trip meters. You are stuck with the original choice of mph or kph as major and minor speedo labels. 1st find a manual 😁

I think the Hungarian models were made only as automatics. 😀

Sometimes I just sit and think. Other times I just sit.

Bung

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#3362489 9-Apr-2025 22:19

No they are available in some markets with a 6 speed manual gearbox. That doesn’t help outdoorsnz who needs the FM for his vehicle so he can read it.

Wheelbarrow01

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#3362497 9-Apr-2025 23:50

outdoorsnz:

Thanks for all the reply's. Confirmed what I thought was correct.

So what are you saying? Has the car done 20,000 miles but RUCs have only been paid to 20,000kms?

outdoorsnz

674 posts

Ultimate Geek

#3362532 10-Apr-2025 09:30

Wheelbarrow01:

outdoorsnz:

Thanks for all the reply's. Confirmed what I thought was correct.

So what are you saying? Has the car done 20,000 miles but RUCs have only been paid to 20,000kms?

Sorting it out with NZTA. Will post back on the outcome. Might just leave it at that for now as there are some other factors that I won't mention for privacy reasons. But take a guess...

outdoorsnz

674 posts

Ultimate Geek

#3362773 10-Apr-2025 19:09

OK have got this all sorted now! Phoned NZTA and got a very helpful person, gave me a ref # and took the car to vinz to get the odometer inspector to sight and verify the odometer reading in miles.

Viv from vinz was very helpful, she rang NZTA special line and sorted it for me. Took awhile.

AND! ChatGPT was a little wrong. The issue was when vehicle was imported, who ever put the vehicle down as being in k's which meant everything got out of whack when entering miles odo and buying k's.

So now I can buy RUC units in miles not k's. ie. 1 unit = 621 miles. No conversions required. And says Miles on ruc page.

Was quite over in the k's. Someone is getting a bill...

RUKI

1402 posts

Uber Geek

#3363696 13-Apr-2025 14:07

I work with various JDM speedometers - developing solutions for converting them from Japanese to English. In some makes and models it is possible to convert speedometer (aka Instrument Cluster or Combination Meter) from KMH to MPH or from MPH to KMH. Examples where I have done that include some Nissan, Suzuki, Hyundai Ioniq, Toyota. In some models (e.g. some Lexus) the change is quite complex and may require reprogramming various ECUs (e.g. BCM) and not just speedometer to change MPH <->KMH.

For the case where such conversion / reprogramming is challenging - the very advanced Geek may wish to build CAN Bus to KMs converter with the additional display to show the mileage in KMs. It is not that hard, just labor some. If one wants to play - I have spare USB to OBD CAN Bus tracer (aka Can Hacker) available :)

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