An open shoulder tread pattern is a drive tyre design in which the side grooves extend from the centre of the tread surface out to the outer edges of the tyre. Unlike a closed shoulder design that presents a continuous rib along each side of the tread band, 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 occupied 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 side grooves that channel water, mud and debris 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 in contact with the road surface. Each individual block acts as a separate grip element, and the open channels between blocks allow the tyre to adapt to uneven surfaces. When the tyre rolls over mud, gravel or standing water, the open grooves provide escape paths for displaced material, maintaining contact between the rubber and the road. This is why open shoulder tyres deliver superior traction in conditions where closed shoulder designs would struggle with aquaplaning, mud packing or surface slipping.
Grooves extend edge to edge across the full width of the tread band, channelling water and debris away from the contact patch for maximum traction in wet conditions.
Separated shoulder blocks create more biting edges that grip loose, uneven and unsealed surfaces where closed patterns would slip.
The open groove geometry naturally expels mud, rocks and packed material as the tyre rotates, preventing loss of traction through tread build-up.
Specialised ribs at the base of the grooves prevent stones from piercing the casing while still allowing natural ejection 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 variety of surface conditions. These are the main use cases where open shoulder tyres outperform their closed shoulder counterparts:
Trucks operating on regional routes across Antigua encounter a wider variety of road conditions than long-haul vehicles. Routes include urban streets with potholes, access roads to industrial estates, approaches to freight wharves at English Harbour and Jolly Harbour, and rural roads between Saint John's, All Saints, Parham and Swetes. Open shoulder tyres handle the frequent acceleration, braking and turning that regional cycles demand while maintaining traction on the varied surfaces these trucks encounter every day.
Trucks that divide their time between sealed roads and unsealed construction sites need drive tyres that perform well in both environments. Open shoulder patterns provide the traction required to climb muddy slopes, navigate gravel yards and maintain control on loose aggregate. The self-cleaning tread prevents mud and clay from packing into the grooves, which would eliminate traction entirely in a closed shoulder tyre. Construction material carriers, concrete mixers and tippers all benefit from open shoulder drive tyres when working across Antigua's active building and resort development sites.
In a tropical climate like Antigua's, where heavy rain can occur throughout the year and coastal salt spray accelerates surface degradation, the wide side 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 wet-weather operations. For fleets that haul freight regardless of weather along routes between Saint John's, Bolans, Willikies and Codrington, open shoulder drive tyres are a critical safety specification.
Mixed service refers to any operation in which trucks regularly move between highway driving and off-road or unsealed conditions. This includes agricultural transport, general haulage to unpaved sites, utility service vehicles and port operations at English Harbour. Open shoulder tyres with cut- and chunking-resistant compounds are designed specifically for the abrasive surfaces and sharp debris that mixed service trucks encounter. The open groove geometry prevents stone punctures while the reinforced compounds resist the cuts and chunking that would quickly 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 capacity and operational demands.
Tread depth is measured in thirty-seconds of an inch (North American market) or millimetres (Antiguan market) and correlates directly with tyre service life and traction capacity. Deeper tread bands provide more material to wear through before the tyre reaches its legal minimum depth, and 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 available 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 under demanding Antiguan road conditions.
Void ratio is the proportion of the 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 there is still significant variation within the open shoulder category. A higher void ratio improves self-cleaning, water evacuation and traction on loose surfaces, but 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, a tyre with a moderate open shoulder 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 trade-off.
Stone ejection is a critical differentiator between open shoulder drive tyres. Because the wide grooves of an open shoulder pattern are more susceptible to trapping rocks and sharp debris, the better open shoulder tyres incorporate ribs or ejection platforms at the base of the primary grooves. These features prevent stones from penetrating far enough to reach the casing while allowing them to be released during normal rotation. The Hanksugi HS68 stone protection system 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 casing damage costs far exceed the savings from choosing a less capable tyre. You can compare open shoulder tyre specifications using our cost calculator per kilometre.
Hanksugi manufactures three open shoulder drive tyre models, each designed for specific operating conditions and regional markets. All three feature aggressive tread patterns with self-cleaning groove geometry, stone protection and durable casings designed for retreading.
Robust drive tyre with M+S pattern and multi-layer anti-puncture laminations. The open shoulder design provides aggressive, self-cleaning traction for roads in poor condition and demanding operating environments.
HATT 3+1 compound technology delivers lower cost per kilometre with superior rolling resistance and fuel savings. Designed for Antiguan highway conditions and tropical operating environments.
The choice between open and closed shoulder drive tyres depends on your primary operating conditions. Neither design is universally superior; each is optimised for different duty cycles. 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 dirt | Moderate — continuous shoulder rib limits bite on loose material |
| Performance in Wet Conditions | Superior — wide side grooves evacuate water quickly | Good — narrower channels adequate for highway rainfall |
| Fuel Economy on Highway | Moderate — higher void ratio slightly increases rolling resistance | Excellent — continuous shoulder reduces friction and fuel consumption |
| Highway Tread Life | Good — separated blocks can wear faster at sustained speeds | Excellent — uniform pressure distribution maximises mileage |
| Self-Cleaning Capacity | Excellent — debris is naturally expelled through open channels | Limited — closed edges trap material more readily |
| Noise Level | Higher — more air passing through open grooves generates road noise | Lower — continuous shoulder reduces noise at highway speeds |
| Ideal Application | Regional, mixed service, on/off-highway, construction | Long-distance highway, high-speed routes, high-mileage operations |
| Hanksugi Models | HS68, , HS28+ Titan Trax | , HS58 |
The table below lists all sizes available in the Hanksugi open shoulder drive tyre range. Click any size to see detailed specifications, load indices and compatible models on the dedicated size page.
| Size | Model | Ply Rating | Tread Depth | Application | Market |
|---|---|---|---|---|---|
| 11R22.5 | HS68 | 16 PR | 20.6 mm | Regional / Long-Haul | Antigua and Barbuda |
| 295/75R22.5 | HS68 | 14 PR | 20.6 mm | Regional / Long-Haul | Antigua and Barbuda |
| 11R24.5 | HS68 | 16 PR | 20.6 mm | Regional / Long-Haul | Antigua and Barbuda |
| 285/75R24.5 | HS68 | 14 PR | 20.6 mm | Regional / Long-Haul | Antigua and Barbuda |
| 11R22.5 | 16 PR | 19/32nds | Mixed Service / On-Off Road | Antigua and Barbuda | |
| 11R24.5 | 16 PR | 19/32nds | Mixed Service / On-Off Road | Antigua and Barbuda | |
| 295/80R22.5 | HS28+ Titan Trax | 18 PR | 22 mm | Drive on Highway | Antigua and Barbuda |
Need help choosing the right size? Use our tyre cost calculator to compare cost per kilometre between sizes and models, or contact our team for a fleet consultation.