John Brett

John is a professional engineer with 50 years experience.

John has designed and built many cars, trucks, and vehicle assembly facilities.

John has worked on design of roads, bridges, cranes, transmission towers, and buildings, and operation, maintenance and upgrade of hydro and gas turbine power stations.

John was a LVV Certifier for 13 years. John has long been a whistle-blower, expressing the view that the LVV system is dangerously deficient. John's authority was revoked in December 2012.

John rides a 1992 Yamaha FJ1200ABS, and is also a keen road and off road cyclist.


“The LVVTA has brought it to my attention that statements I have made in relation to it and its employees may have been perceived as defamatory.

I sincerely regret that and apologise for any harm caused. I have taken down the statements identified by the LVVTA of concern to it.

I have strong views about the low volume vehicle certification process and intend in the future to direct my energies into the public inquiry now being held in relation to it.”

John Brett 7th October 2015


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Wheel Spacers FAQ’s

Wheel Spacers are the subject we are most common asked about.
The rules are all on the LVVTA website in the Wheels and Tyre Standard 2005-00


Non-Legal spacers


SPACERS need to be ‘Hub Centric’ and ‘Wheel-Centric’, or a centering ring has to be made to centralise the wheel and the spacer.
This means in practice, that wheel spacers will need to be custom-made to suit the specific vehicle and wheel combination.
Also you will probably need to fit longer wheel studs to keep the required thread engagement of the nuts.

ADAPTORS are Centered on the hub by the tapered nuts hulding them onto the hub. The wheel is then Centered on the adaptor by the tapered nuts holding the wheel on.
Centering spigots for the adaptor or the wheel are not required. (See LVV Standard 2005-00)


The LVV Standard says that adaptors ‘are manufactured by someone competent and experienced in the type of work undertaken, who has the necessary equipment to carry out the manufacturing correctly’
We do not know many people in Japan, or China, and find this clause to be unhelpful.
Instead we:-

1 Do a material hardness test to determine the likely material. Most adaptors are T6 Aluminium Alloy, which has a hardness of 40 to 45 Rockwell C. We do NOT want to accidentally certify any adaptors made of soft alloy, zinc castings or shite metal!!

2 Do a simple stress calculation (using a spreadsheet template) to determine the shear stress between the bolts, and the shear under the bolt head. The adaptor should be equal in strength to the wheel studs. We find that adaptors THINNER than about 12mm are usually over-stressed.

Spacers are not permitted to be more than 20 mm
Adaptors are not permitted to be more than 27 mm,
Most adaptors are to compensate for wheels with wrong offset offset, (not to effect a change in stud pattern).

Wheels flying off can kill people (it has happened more than once)
Wheels flying off can make controlling the vehicle a tad tricky, especially since it is likely to happen under hard cornering.
People getting killed is clearly to be avoided- as is getting sent to jail for manslaughter.

Failed Wheel Adaptor

Failed Wheel Adaptor


Additional information-
Tyre and rim sizes-
The LVVTA compatibilty chart can be found here

This is based on the best information available at the time the chart was written- however a Tyre manufacturers reccomendation takes preference- so check with the tyre manufacturer if you want to use a combination outside these guidelines.

Hope this clears up any confusion, and helps you to get it right before going for your Cert.

164 comments to Wheel Spacers FAQ’s

  • andrew

    Can I trim metal from my lower control arm to clear the inside hub of my wheel to prevent rubbing and avoid having to run spacers? Cheers

  • johnbrett

    No sorry- the manufacturer spend millions on reducing the cost of that arm, and more on testing it to destruction. Only a fool would decide that some metal could be trimmed off (without any testing) and it will still be OK


  • Ming

    I upgrading my CRZ brake to DC5 caliper with S2000 disk. But need a 1mm spacer or washer inside the disk (correct, inside the disk, ABS sensor side) to push the disk outward, to centerlines the disk in the middle of the caliper. Will this OK to LVV? Cheer

  • Sam

    Has anyone successfully purchased HubCentric Spacers through ?? I am looking into placing an order as all of the bolt on stuff available here in NZ starts at 15mm which is too big for my purpose.

  • johnbrett

    When they are bolt-on we call them adaptors. There is no minimum thickness for adaptors, and no material specification. I always check that the material is T6 Alloy and do a stress analysis. I find that Adaptors LESS than 15 mm thick are too weak and likely to fail.

    Since there are no rules, you could go ahead and get adaptors less than 15mm LVV Certified, if you are not worried about wheels coming off.

    Better idea is to use SPACERS with longer studs. Spacers need to be hub-centric and wheel-centric, or have a centering ring fitted.

  • Rick

    Hi, Do adapters require a cert if they are fitted to a trailer?

  • johnbrett

    Hi Rick- There is no mention in the WOF guide- for trailer wheels,-wheels-and-hubs/tyres-and-wheels. The only thing I can see the inspector could fail it on is- insecurely attached, or insufficent thread engagement. Hope tghis helps- John

  • Peter

    Is it possible to cert spacers fitted on a adapter?
    So i have a 25mm adapter changing the stud pattern from 4×140 to 4×114 but my wheel is a little to close to shock so could i add a 10mm spacer hub and wheel centric to the adapter?

  • Rob

    I want to fit a set of wheels which are perfectly compatible in size, width & offset – however the centre bore size of the wheels is 57mm & the car has only 54mm centre hub size. Is that 3mm “gap” legal? Do I have to fit some sort of ring to fill in the gap?

  • johnbrett

    Hi Rob- the wheel needs to be centered on the hub, but if there are no spacers fitted, the tapered wheel nuts center in the tapered holes in the wheels and serve that function. If spacers are fitted, this introduces bending loads on the wheel studs, so then a centering ring is needed. So the answer is- if there are no spacers fitted, a centering ring is not required. Hope this helps, John

  • tim

    do my 20mm spacers need to be bolted to the hub or can it sit like a washer plate between the rim and hub to meet cert requirements?

  • johnbrett

    See the LVVTA requirements- Spacers need to be retained on the hub when the wheel is removed. Typically a single countersunk screw is enough.

  • Brendan

    Just to clarify, I only need a few mm to clear my breaks, I can run a 5mm slip on spacer as long as it is attached to the disc? The factory wheel center thingy still sits out further than the spacer.

  • johnbrett

    Hi Brendan- Yes a 5 mm slip on spacer is fine, so long as it meets the LVV requirements, and is LVV Certified Regards- John

  • Damaraz

    Hey there
    If I have a et6 offset set of 17×8″.
    And maximum spacer thickness is 20mm can I run 2x20mm spacers to get it to the factory et46 offset?

  • johnbrett

    Hi Damaraz

    Easy answer-

    Sorry, John

  • Nigel

    Hi. I am getting a set of adapters to allow me to fit bigger brakes. The adapters conform to EU regulations (German). Will these need to be certified or can they be fitted and legal without any further action ? Thanks.

  • johnbrett

    Hi Nigel
    The vehicle will still need to be LVV Certified. It is the performance of the whole vehicle which is being assessed. The bigger brakes also need Certification, so you should get both done at the same time.


  • Nigel

    Hi John.
    Thanks. How do I go about getting them certified and what is the approximate cost? Cheers Nigel

  • johnbrett

    Hi Nigel
    You will have to find a Low Volume Vehicle Certifier near you. If you have trouble, I suggest you phone NZTA. Sorry I can’t be more help.

  • Nigel

    Hi John.
    Many thanks I’m on to it. Wouldn’t want to run something that could bite me! Cheers.

  • Cheyne

    Hi john

    Are adapters that change the stud pattern from 5×120 to 5×114.3 and are 15-20mm thick able to be certified?


  • johnbrett

    Hi Cheyne
    In principle yes. A Certifier should always check that the material is suitable, and that there is sufficient area of metal for the load. 15 mm thick should work if the material is a 6068 T6 alloy.

  • Kevin

    A colleague of mine has had two incidences where a flat tyre was replaced by the spare, but the spacer not removed. In the second incident, this left a pretty loose wheel after a few km.
    What measures are in place to make it obvious that spacers are in use?
    First instance by a Road side service
    In the second instance the wheel nuts were checked by a second person after the tyre replaced and put the loose fitting down to not enough porridge.

  • johnbrett

    Hi Kevin

    The spacers should be fixed to the hub, usually by a couple of countersunk screws. It should be obvious to anyone changing the wheel that there is a spacer there- plus the spacers are noted on the LVV Certification Plate.

    You have not explained WHY the spare wheel came loose- if the spare was fitted over the spacer it should tighten up the same as the normal wheel.
    Having a spare wheel is NOT a WOF requirement – if you are fitting different wheels and tyres, or spacers or adaptors, and if you want to carry a spare wheel, it seems sensible to make sure that you have a spare that will still fit!
    What makes you think that the spacer should be removed? Since the wheel studs would be longer than standard, (because of the spacer) there may not be enough thread for the nuts to grip the wheel if you removed the spacer.
    Always double check that wheel-nuts are tight- I re-check them when the vehicle is on the ground.

    Hope this helps

  • Kevin

    Thanks John.
    Not my car. Car was purchased by a colleague as is. Wheels on car possibly aftermarket and prior purchase.

    Picture becoming a little clearer here. Right rear Flat tyre replaced by another person who mentioned the nuts were a bit loose. The spare tyre looks to be on a standard rim – not low profile). The one removed was a DTM Mag ( 2006 Nissan TII DA or T11) “Tightness” of nuts compared to one or two on the right front. which didn’t appear to have as much meat on the thread as say a Hilux.

    The nuts holding the spare wheel on were tightened a little further ( Double checked). After the person drove home (50 – 70 km) two of the nuts were on the ground).

    On taking the car to the mechanic, the mechanic advised that the spacer needs to be removed before putting on a spare.

    On inspection the spacer was damaged and had to be replaced. Now after the event, as under stood the spacer is made of “plastic – maybe ptfe” So one does wonder how this was missed by the person changing the tyre. Noting the first time it happened the spare had been fitted by a roadside service professional.

    Just looking to see if there is a way to avoid this in the future. (Action here is to put a tag on the tyre iron.)

    The manual wasn’t consulted at the time.
    Mind next time I’ll take the wheel off myself and check.

  • johnbrett

    This is a good example of why wheel spacers need to be LVV Certified. A spacer made from ‘Plastic’ would not get certified, you have said that there was insufficient thread on the wheel stud (which is part of an LVV Inspection)
    You haven’t said that the vehicle was LVV Certified- if it was there would be grounds for a complaint.

    The way to avoid this in the future is for the WOF agent to fail the vehicle, or the Police to pink sticker it. A properly modified and certified vehicle needs no special warnings.

  • Kevin

    Interesting conundrum as the replacement plastic type part was easily sourced at the garage so to speak. Searching for manual now. Happy to take off line. have found contact details for mag supplier

  • Kevin

    Mystery solved, after discussion with a Mag wheel supplier. And then googling locator ring.

    Must be removed when replacing the aftermarket Mag with the Car manufacturer supplied spare.

    What is a Hub Centric Ring?
    The centric ring is a device used with the rims and are installed between the car wheel hub and the rim. The purpose of the hub centric ring is to fill the empty space between the wheel hub and the center bore of the rim. Centric rings are usually made of durable industrial plastic. Centric rings are also made of aluminum. Improve the fitment & balance of your aftermarket wheels with hub centric rings
    What are centric rings needed for?
    Centric rings are needed when the hub hole (the center bore) on the rim is larger than the wheel hub of the car. The rim manufacturers deliberately make the hub ring as large as possible for the rim, taking in to consideration the hub hole, to allow the same rims to be sold for the various different models of car using hub centric rings.
    Centric rings are usually needed only for post-sale rims, since the original rims usually come with a center bore of the right size. Usually the hub centric rings are used with alloy wheels, but sometimes steel rims may need hub centric rings.
    The purpose of the centric ring is to perfectly center the alloy wheel to the wheel hub and hence prevent vibration to the steering wheel during driving and the shaking which typically appears around speeds of 40-60 mph.
    – Hubcentric

    The mag wheel supplier applies stickers to the spare. And have very good feedback from the supplier. Trap for young players may be purchasing a car with Mags and the spare is not a Mag

  • johnbrett

    Hi Kevin

    Thank you for clarifying this. Calling the item a ‘Spacer’ is what caused the confusion. Centering rings or similar ARE called for by the LVV Standard, when spacers are fitted.



  • Phil

    Hi John,

    I’m looking to use spacers to give clearance required for a set of larger rims to be fitted. 15 to 17″
    Does fitting these new items require compliance in NZ?
    Also, what is the largest thickness a “bolted to existing wheel studs type spacer” can be?


  • johnbrett

    Hi Phil
    Changing wheel size does not require certification, providing rolling radius and track width changes are within limits.
    Spacers and adaptors ALWAYS need LVV Certification, and there are many factors to consider. There is a limit of 27 mm for adaptors, but that doesn’t mean that 27 mm will be automatically approved on your vehicle.
    The Certifier has to assess a range of issues, including driving, steering and braking.



  • Amos Dalkie

    need to change wheel offset, not pcd, is hub centric 25mm all breezy? going from 4×00 to 4×100
    refer to below product×100-honda-25mm-pair

  • johnbrett

    Hi Amos
    As you are adding spacers (or adaptors) you will need LVV Certification. The Scarles items you link to look OK, but it’s the overall effect on the vehicle that matters. There are situations where such spacers are not safe, other situations where they are OK, depends on vehicle model, suspension, wheels fitted etc. The Certifier will do a thorough drive test including some hard braking, hard cornering. You will need to find a LVV Certifier. Cheers

  • Minh

    Hello John,
    I was wondering if you could provide some advice on wheels with factory spacers attached to them. The wheels are a reputable brand and have the same offset and hub bore as the factory wheels on the vehicle. The spacers themselves are bolted to the wheels and use the same wheel bolts and seating as the factory wheel. Would a LVV certification be required to use these? Thanks

  • johnbrett

    Hi Minh. It sounds as if these wheels and spacers would meet all the requirements without any problem. They would still need to be checked by a LVV Certifier, as there are still many unsafe items out there. Once it has been LVV Certified, any WOF agent or Policeman will have the confidence that the vehicle is all safe.

    Good luck


  • Samsam

    Hi John. I have a 12mm spacer/shim fitted BEHIND the hub. Not between the hub and wheel like the ones mentioned here. I can’t find any information on weather this needs to be certed or not? Will it pass wof?

  • johnbrett

    Hi Samsam
    I can’t understand this- what is the spacer there for? Is it to do with the wheel attachment, or the brake rotor? I would check with a WOF agent, and see whet they think.

  • johnbrett

    Hi Samsam
    I see what you mean.
    I can imagine issues if not done properly.
    I don’t know of ANY specific rules, or requirements for that, other than ‘General Safety’.



  • Ben

    Hi John,
    I want to fit 20-25mm bolt on spacers simply for the look, (as the wheels/tyres sit inside the wheel arch).
    Do I need these cirtified?
    Obviously I would use a spacer with the same stud pattern as my car has.

  • johnbrett

    Hi Ben

    Yes, that will need to be Certified


  • Craig

    You mention a spreadsheet to do the stress test. Is this available?

  • johnbrett

    No, spreadsheet is just part of my engineering assessment. You can work out the shear areas yourself quite easily. I used the wheel stud strength as my limiting load. I also did a material analysis to make sure the adaptors were made of a suitable material. None of this is required by any current LVV Standard, legally you can fit adaptors as thin as you like, made of any old pot-metal.



  • ryan

    Hi John,
    i want to put spacers on my RX3 that has had adjustable suspension fitted in the front – is there a minimum clearance required from the inside edge of the rim to the suspension strut? straight onto the hub at the minute there is about 2mm clearance, so am looking at 6-9mm spacers. any bigger and it would create issues on the outside of the tyre rubbing on the guard.
    Also with the spacers, im looking at 1’s that are a reputable brand that will sit centrally because they are not “multifit” so to speak, just holes to suit the stud pattern, my question is, do they also have to be snug around the central bit ( inner circle/ center bore) and do they have to be permanently fixed to the hub, thank you Ryan.

  • johnbrett

    Hi Ryan
    There is NO minimum distance specified between rim and strut. If the rim does not touch, it should be OK for a WOF. If it has adjustable struts, it should have been LVV Certified. The wheels should be the same as were on when certified, or a re-certification will be needed. The requirement for spacers are in the LVV Standard 205-00 which can be downloaded from here:

    There is no charge for this free advice, but could I ask that you make a small donation to my ‘Give-a Little’ campaign? This is to cover legal costs for defending myself from Defamation charges made by Mr Johnson of the LVVTA.
    If you did want to, just click though to the Give-a Little page.



  • Mathew

    To run a 15mm spacer the factory studs are to long to fit the wheel flush against the spacer. It is possible to cut the stud down and get it certed or are shorter studs required

  • johnbrett

    Hi Mathew
    I see no problem in cutting studs down to length. I can’t understand the factory studs being too long- surely they were sized for NO spacer.
    So long as the studs have sufficient thread engagement, there should be no problem.
    Make sure though nthat the spacers meet all the requirements

    There is no charge for this free advice, but could I ask that you make a small donation to my ‘Give-a Little’ campaign? This is to cover legal costs for defending myself from Defamation charges made by Mr Johnson of the LVVTA.
    If you did want to, just click though to the Give-a Little page.



  • Mathew

    Hi John thanks for that.sorry I am using the wrong word I meant adapter with 15mm the factory bolts sit out to far stopping the wheel from sitting against the adapter. sure visa or something like that accepted

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