An open shoulder tread pattern is a drive tyre design in which the lateral grooves extend from the centre of the tread surface out to the outer edges of the tyre. Unlike a closed shoulder design that has a continuous rib along each side of the tread, open shoulder tyres have distinct, separated blocks across the full width of the contact patch. This creates a higher void ratio — the percentage of the tread surface taken up by grooves rather than rubber — which fundamentally changes how the tyre interacts with the road surface.
The defining features of an open shoulder pattern include wide lateral grooves that channel water, mud and slush away from the contact patch; aggressive block edges that bite into loose surfaces to generate traction; and a self-cleaning geometry that expels debris and prevents material from packing into the tread. These features make open shoulder drive tyres the preferred choice for any application where surface conditions are variable, unpredictable or consistently demanding.
From an engineering perspective, the open shoulder pattern works by maximising the number of biting edges that contact the road surface. Each individual block acts as a separate grip element, and the open channels between blocks allow the tyre to conform to uneven surfaces. When the tyre rolls through mud, gravel or standing water, the open grooves provide escape routes for the displaced material, maintaining contact between the rubber and the road. That is why open shoulder tyres deliver superior traction in conditions where closed shoulder designs would struggle with aquaplaning, mud packing or surface slipping.
The grooves extend from edge to edge across the full width of the tread, channelling water and debris away from the contact patch for maximum wet traction.
Separated shoulder blocks create more biting edges that grip loose, uneven and unsealed surfaces where closed patterns slip.
The open groove geometry naturally expels mud, rocks and packed material as the tyre rotates, preventing the loss of traction caused by build-up in the tread.
Specialised ribs at the base of the grooves stop stones from piercing the casing while allowing them to be ejected naturally during rotation.
Choosing the right shoulder pattern is one of the most important decisions a fleet manager or owner-operator can make when specifying drive tyres. Open shoulder drive tyres are designed for applications where the operating environment demands aggressive traction, resistance to debris and the ability to maintain performance across a range of surface conditions. These are the main use cases where open shoulder tyres outperform their closed shoulder counterparts:
Regional trucks operating within a radius of 320 to 800 km face a wider range of road conditions than long-haul vehicles. Their routes include potholed city streets, access roads to industrial parks, approaches to freight depots and secondary rural roads. Open shoulder tyres handle the frequent acceleration, braking and turning that regional cycles demand, while maintaining traction across the varied surfaces these trucks encounter every day.
Trucks that split their time between sealed highways and unsealed worksites need drive tyres that perform in both environments. Open shoulder patterns provide the traction needed to climb muddy slopes, negotiate gravel yards and keep control on loose aggregate surfaces. The self-cleaning tread stops mud and clay from packing into the grooves, which would completely eliminate traction on a closed shoulder tyre. Construction material carriers, concrete mixer trucks and tippers all benefit from open shoulder drive tyres.
In regions with frequent rain, slush or standing water, the wider lateral grooves of open shoulder tyres channel water away from the contact patch far more effectively than closed shoulder designs. This reduces the risk of aquaplaning and maintains positive traction during operations in wet weather. For fleets operating in regions with daily rainfall, open shoulder drive tyres are a critical safety specification.
Mixed service describes any operation in which trucks move regularly between highway driving and off-road or unsealed conditions. This includes forestry operations, agricultural transport, oilfield service, utility work and municipal applications. Open shoulder tyres with compounds resistant to cuts and chunking are designed specifically for the abrasive surfaces and sharp debris that mixed service trucks encounter. The open groove geometry guards against stone puncture, while the reinforced compounds resist the cuts and chunking that would destroy standard highway tyres.
When evaluating open shoulder drive tyres for your fleet, three technical specifications determine how well a tyre will perform in your specific application. Understanding these metrics helps you make an informed purchasing decision and avoid costly mismatches between tyre capability and operational demands.
Tread depth is measured in thirty-seconds of an inch (North American market) or millimetres (Anguilla market) and correlates directly with tyre service life and traction capability. Deeper treads provide more material to wear down before the tyre reaches the legal minimum depth, and they maintain the groove volume needed for self-cleaning and water evacuation. Open shoulder drive tyres typically feature depths between 19/32 and 29/32, with deeper options for severe service applications where maximum tread life justifies the slightly higher rolling resistance. The Hanksugi HS68 delivers 20.6 mm of depth, while the HS28+ Titan Trax offers 22 mm for extended service in demanding highway conditions in Anguilla.
The void ratio is the proportion of groove area relative to the total tread surface area. Open shoulder drive tyres have a higher void ratio than closed shoulder tyres by definition, but even so there is significant variation within the open shoulder category. A higher void ratio improves self-cleaning, water evacuation and traction on loose surfaces, but it reduces the amount of rubber in contact with the road at any given moment. This means higher void ratios trade some highway stability and tread life for off-road capability. For mainly regional use with occasional off-road access, an open shoulder tyre with a moderate void ratio such as the HS68 balances both needs. For intensive off-road use, a more aggressive pattern delivers the traction advantage that justifies the compromise.
Stone ejection is a critical differentiator between open shoulder drive tyres. Because the wide grooves of an open shoulder pattern are more prone to trapping rocks and sharp debris, the best open shoulder tyres incorporate ejection ribs or platforms at the base of the primary grooves. These features stop stones from penetrating deeply enough to reach the casing while allowing them to be released during normal rotation. The stone-protection system of the Hanksugi HS68 is designed specifically for this purpose, using a groove geometry that prevents stone retention while maintaining the open-channel flow needed for self-cleaning. Fleet operators who overlook this specification often find that the cost of casing damage far outweighs the savings of choosing a less capable tyre. You can compare open shoulder tyre specifications with our cost-per-kilometre calculator.
Hanksugi manufactures three open shoulder drive tyre models, each designed for specific operating conditions and regional markets. All three feature aggressive tread patterns with a self-cleaning groove geometry, stone protection and durable casings designed for retreading.
Robust drive tyre with an M+S pattern and multi-layer anti-puncture plies. The open shoulder design provides aggressive, self-cleaning traction for poorly maintained roads and demanding conditions.
HATT 3+1 compound technology delivers a lower cost per kilometre with superior wear resistance and fuel savings. Designed for highway conditions in Anguilla.
The choice between open and closed shoulder drive tyres depends on your main operating conditions. No design is universally superior; each is optimised for a different work cycle. The table below summarises the key differences to help you make the right decision for your fleet. For a detailed guide, read our full comparison of closed shoulder vs. open shoulder drive tyres.
| Feature | Open Shoulder | Closed Shoulder |
|---|---|---|
| Traction on Loose Surfaces | Excellent — aggressive block edges grip gravel, mud and soil | Moderate — the continuous shoulder rib limits the bite on loose material |
| Wet Weather Performance | Superior — the wide lateral grooves evacuate water quickly | Good — narrower channels are adequate for rain on the highway |
| Highway Fuel Economy | Moderate — the higher void ratio slightly increases rolling resistance | Excellent — the continuous shoulder reduces friction and fuel consumption |
| Highway Service Life | Good — separated blocks can wear faster at sustained speeds | Excellent — even pressure distribution maximises mileage |
| Self-Cleaning Ability | Excellent — debris is expelled naturally through the open channels | Limited — closed edges trap material more easily |
| Noise Level | Higher — more air passing through the open grooves generates road noise | Lower — the continuous shoulder reduces noise at highway speeds |
| Ideal Application | Regional, mixed service, on/off-highway, construction | Long-distance OTR, motorway, high-speed high-mileage routes |
| Hanksugi Models | HS68, , HS28+ Titan Trax | , HS58 |
The table below lists all the sizes available in the Hanksugi open shoulder drive tyre line. Click any size to see detailed specifications, load ratings and compatible models on the dedicated page.
| Size | Model | Ply Rating | Tread Depth | Application | Market |
|---|---|---|---|---|---|
| 11R22.5 | HS68 | 16 PR | 20.6 mm | Regional / Long-Haul | Anguilla |
| 295/75R22.5 | HS68 | 14 PR | 20.6 mm | Regional / Long-Haul | Anguilla |
| 11R24.5 | HS68 | 16 PR | 20.6 mm | Regional / Long-Haul | Anguilla |
| 285/75R24.5 | HS68 | 14 PR | 20.6 mm | Regional / Long-Haul | Anguilla |
| 11R22.5 | 16 PR | 19/32nds | Mixed Service / On-Off Road | Anguilla | |
| 11R24.5 | 16 PR | 19/32nds | Mixed Service / On-Off Road | Anguilla | |
| 295/80R22.5 | HS28+ Titan Trax | 18 PR | 22 mm | Highway Drive | Anguilla |
Need help choosing the right size? Use our cost-per-tyre calculator to compare cost per kilometre across sizes and models, or contact our team for a fleet consultation.