Free Interactive Tool
NZ WOF Axle Compatibility Checker
Check if your tyre setup meets WOF same-axle requirements before your inspection. Based on the VIRM and Land Transport Rule: Tyres and Wheels 2001.
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What the NZ WOF Rules Actually Say
These rules come from the Land Transport Rule: Tyres and Wheels 2001 and are checked by WOF inspectors using the VIRM (Vehicle Inspection Requirements Manual), Section 10-1.
Same-Axle Requirements
Both tyres on the same axle (left and right) must match in three ways:
Same Size
Both tyres must have the same size designation. For example, both must be 205/55R16. You cannot have 205/55R16 on the left and 215/55R16 on the right.
Same Construction
Both must be the same carcass type: radial (R), bias-ply (D/B), or run-flat. This rule also applies across all axles. You cannot have radial tyres on the front and bias-ply on the rear.
Same Pattern Type
Both must be the same tread pattern type: symmetrical, asymmetrical, or directional. You cannot mix directional with symmetrical on the same axle.
Cross-Axle Rules
Different axles (front vs rear) have more flexibility, but there are still rules:
Different sizes on different axles: Allowed
You can run 225/45R17 on the front and 245/40R17 on the rear (staggered setup), as long as each axle matches.
Different pattern types on different axles: Allowed
You can have asymmetrical on the front and symmetrical on the rear.
Different construction across axles: Not allowed
All four tyres must be the same construction type. You cannot mix radial and bias-ply anywhere on the vehicle.
Mixing winter and normal tyres: Not allowed
If you fit winter tyres, all four must be winter tyres. Mixing is a WOF fail. Winter tyres require 4mm tread minimum (vs 1.5mm for normal).
Source: VIRM Section 10-1, Land Transport Rule: Tyres and Wheels 2001. Full inspection criteria available at vehicleinspection.nzta.govt.nz
Common Scenarios
These are the situations we see most often. Use the tool above to check your specific setup.
| Scenario | Same Axle | Different Axles |
|---|---|---|
| Different tyre sizes | Fail | OK |
| Different brands, same size/pattern/construction | OK | OK |
| Directional + symmetrical | Fail | OK |
| Radial + bias-ply (cross-ply) | Fail | Fail |
| Different speed ratings | OK* | OK* |
| Load index difference of 2 or less | OK | OK |
| Load index difference of 3+ | Fail | OK |
| Winter + normal mixed | Fail | Fail |
| Run-flat + standard | Fail | Fail |
*Speed ratings do not need to match for WOF, but your vehicle is limited by the lowest-rated tyre fitted.
Tread Depth Requirements
Regardless of axle compatibility, every tyre must meet minimum tread depth to pass WOF:
Normal Tyres: 1.5mm
Measured across the full width of tread that contacts the road, at the shallowest point of the main tread grooves. Our recommendation: replace at 3mm for general driving.
Winter Tyres: 4mm
Much higher minimum due to winter tyre compound design. Winter tyres below 4mm lose most of their cold-weather advantage. These are rare in NZ but common on Japanese imports.
20-cent coin test: Insert a 20c coin into the tread groove. If you can see the "20" text, your tread is getting low. Consider replacement soon.
Frequently Asked Questions
No. Under the Land Transport Rule: Tyres and Wheels 2001, tyres on the same axle must be of the same size designation. Different sizes on the same axle will fail WOF. You can have different sizes on different axles (front vs rear) as long as construction type matches across all four wheels.
No. All tyres on the vehicle must be the same carcass construction. You cannot mix radial and bias-ply (cross-ply) on any combination of axles. This applies to the whole vehicle, not just per-axle. Run-flat tyres also count as a separate construction type.
No. Tyres on the same axle must be the same tread pattern type. Directional, symmetrical, and asymmetrical are all different types and cannot be mixed on the same axle. You can mix pattern types across different axles though (e.g. directional front, symmetrical rear).
No. Speed ratings do not need to match for WOF. Each tyre just needs to meet or exceed the vehicle's maximum speed or the applicable speed limit. However, your vehicle is legally limited by the lowest-rated tyre fitted. For more detail, see our Speed Rating Guide.
No. If you fit winter tyres, all four must be winter tyres. Mixing winter and normal tyres on the same vehicle is a WOF fail. This rule was introduced after fatal accidents involving vehicles with mixed tyre types that showed different grip levels front-to-rear. Winter tyres require 4mm minimum tread depth vs 1.5mm for normal tyres.
Yes, as long as both tyres are the same size, same construction, and same pattern type. Brand does not matter for WOF. That said, matching brands and models gives more predictable handling because grip levels and wear rates will be consistent.
More Tyre Tools and Guides
Build Your Tyre Setup
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Front Left
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Front Right
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Rear Left
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Rear Right
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Compatibility Results
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