Oversize or overmass vehicles
Mass limits
New OSOM notices
From Thursday 9 January 2025, oversize overmass (OSOM) notices will be introduced.
These notices will promote OSOM cross border access by allowing eligible vehicles to:
- travel at night
- have OS access during peak times
- no longer require a 3-year permit.
Eligible vehicles are those that meet dimension and vehicle type requirements, as per the notices.
For more information, call the permits officer on 08 8951 5263.
Single axles and single axle groups (one axle or 2 axles with centre of axle spacing less than 1 m)
| Description of axle or axle group | Mass limit |
|---|---|
| Single steer axle on a motor vehicle | 6 t |
|
Single axle or single axle group fitted with single tyres with section width of: (a) less than 375 mm | 6 t |
| (b) at least 375 mm but less than 450 mm | 6.7 t |
| (c) at least 450 mm | 7 t |
|
Single axle or single axle group fitted with dual tyres on: (a) a pig trailer | 8.5 t |
| (b) a bus licensed to carry standing passengers | 10 t |
| (c) any other vehicle | 9 t |
Twin steer axle groups
| Description of axle or axle group | Mass limit |
|---|---|
| Twin steer axle group without a load-sharing suspension system | 10 t |
| Twin steer axle group with a load-sharing suspension system | 11 t |
Tandem axle groups (at least 2 axles with the centre of axle spacing at least 1 m but not more than 2 m)
| Description of axle or axle group | Mass limit |
|---|---|
| Tandem axle group fitted with single tyres with section width of: (a) less than 375 mm | 11 t |
| (b) at least 375 mm but less than 450 mm | 13.3 t |
| (c) at least 45 0mm | 14 t |
| Tandem axle group fitted with single tyres on one axle and dual tyres on the other axle | 13 t |
|
Tandem axle group fitted with dual tyres on: (a) a pig trailer | 15 t |
| (b) any other vehicle | 16.5 t |
Tri-axle groups (at least 3 axles with centre of extreme axle spacing at least 2 m but not more than 3.2 m)
| Description of axle or axle group | Mass limit |
|---|---|
| Tri-axle group on a vehicle fitted with single tyres with section width of less than 375 mm on all axles or single tyres on one or 2 axles and dual tyres on the other axle or axles | 15 t |
| Tri-axle group on a pig trailer with either single tyres with section width of at least 375 mm, dual tyres on all axles or a combination of those tyres | 18 t |
| Tri-axle group on a vehicle, other than a pig trailer, with either single tyres with section width of at least 375 mm, dual tyres, or a combination of those tyres | 20 t |
Quad axle groups (at least 4 axles with centre of extreme axle spacing at least 3.2 m but not more than 4.9 m)
| Description of axle or axle group | Mass limit |
|---|---|
| Quad-axle group fitted with single tyres with section width of less than 375 mm | 15 t |
| Quad-axle group fitted with single tyres with section width of at least 375 mm or dual tyres | 20 t |
Other axle groups
| Description of axle or axle group | Mass limit |
|---|---|
| Any other axle group not specifically referred to in this schedule | 20 t |
Axle groups fitted with complying road friendly suspension – (each axle group fitted with dual tyres)
| Description of axle or axle group | Mass limit |
|---|---|
| Tandem axle group | 17 t |
| Tri-axle group | 22.5 t |
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