An open shoulder tread pattern is a drive tire design where the lateral grooves extend from the center of the tread surface all the way to the outer edges of the tire. Unlike a closed shoulder design that features a continuous rib running along each side of the tread, open shoulder tires have distinct, separated tread blocks across the entire 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 tire interacts with the road surface.
The defining characteristics of an open shoulder tread pattern include wide lateral grooves that channel water, mud, and slurry away from the contact patch; aggressive block edges that bite into loose surfaces to generate traction; and a self-cleaning geometry that ejects debris and prevents material from packing into the tread. These features make open shoulder drive tires the preferred choice for any application where surface conditions are variable, unpredictable, or consistently challenging.
From an engineering perspective, the open shoulder pattern works by maximizing the number of biting edges that contact the road surface. Each individual tread block acts as a separate gripping element, and the open channels between blocks allow the tire to conform to irregular surfaces. When the tire rolls through mud, gravel, or standing water, the open grooves provide escape paths for displaced material, maintaining contact between rubber and road. This is why open shoulder tires deliver superior traction in conditions where closed shoulder designs would struggle with hydroplaning, mud packing, or surface slippage.
Grooves extend edge-to-edge across the full tread width, channeling water and debris away from the contact patch for maximum wet traction.
Separated shoulder blocks create more biting edges that grip loose, uneven, and unpaved surfaces where closed patterns slip.
Open groove geometry naturally ejects mud, rocks, and packed material as the tire rotates, preventing traction loss from tread packing.
Specialized ribs at groove bases prevent stones from drilling into the casing while still allowing natural expulsion during rotation.
Choosing the right shoulder pattern is one of the most consequential decisions a fleet manager or owner-operator can make when spec'ing drive tires. Open shoulder drive tires are engineered for applications where the operating environment demands aggressive traction, debris resistance, and the ability to maintain performance across a range of surface conditions. Here are the primary use cases where open shoulder tires outperform their closed shoulder counterparts:
Regional trucks that operate within a 200-to-500-mile radius encounter a wider variety of road conditions than long-haul vehicles. Routes include urban streets with potholes, industrial park access roads, loading dock approaches, and rural secondary highways. Open shoulder tires handle the frequent acceleration, braking, and turning that regional duty cycles demand while maintaining traction on the varied surfaces these trucks encounter every day.
Trucks that split their time between paved highways and unpaved job sites need drive tires that perform in both environments. Open shoulder patterns provide the traction needed to climb muddy grades, navigate gravel yards, and maintain control on loose aggregate surfaces. The self-cleaning tread prevents mud and clay from packing into grooves, which would eliminate traction entirely on a closed shoulder tire. Construction material haulers, ready-mix concrete trucks, and dump trucks all benefit from open shoulder drive tires.
In regions with frequent rain, snowmelt, or standing water, the wider lateral grooves of open shoulder tires channel water away from the contact patch far more effectively than closed shoulder designs. This reduces the risk of hydroplaning and maintains positive traction during wet-weather operations. For fleets operating in the Pacific Northwest, Southeast, or Gulf Coast regions where precipitation is a daily operational factor, open shoulder drive tires are a safety-critical specification.
Mixed service describes any operation where trucks regularly transition between highway driving and off-road or unpaved conditions. This includes logging operations, agricultural hauling, oilfield service, utility work, and municipal applications. Open shoulder tires with cut-and-chip resistant compounds like the Hanksugi HS84 are specifically engineered for the abrasive surfaces and sharp debris that mixed service trucks encounter. The open groove geometry prevents stone drilling while the reinforced compounds resist the cuts and tears that would destroy standard highway drive tires.
When evaluating open shoulder drive tires for your fleet, three technical specifications determine how well a tire will perform in your specific application. Understanding these metrics helps you make an informed purchasing decision and avoid costly mismatches between tire capability and operational demands.
Tread depth is measured in 32nds of an inch (US market) or millimeters (LATAM/international market) and directly correlates with tire service life and traction capacity. Deeper treads provide more material to wear through before the tire reaches minimum legal depth, and they maintain the groove volume needed for self-cleaning and water evacuation. Open shoulder drive tires typically feature tread depths between 19/32nds and 29/32nds, with deeper options suited for severe service applications where maximum tread life justifies the slightly higher rolling resistance. The Hanksugi HS68 delivers 20.6 mm of tread depth, while the HS28+ Titan Trax provides 22 mm for extended service in demanding Latin American highway conditions.
Void ratio is the proportion of groove area to total tread surface area. Open shoulder drive tires have a higher void ratio than closed shoulder tires by definition, but there is still meaningful 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 primarily regional highway use with occasional off-road access, a moderate void ratio open shoulder tire like the HS68 balances both needs. For heavy off-road use, a more aggressive pattern delivers the traction advantage that justifies the trade-off.
Stone ejection is a critical differentiator among open shoulder drive tires. Because the wide grooves of an open shoulder pattern are more susceptible to trapping rocks and sharp debris, the best open shoulder tires incorporate stone ejection ribs or platforms at the base of the primary grooves. These features prevent stones from penetrating deep enough to reach the tire casing while still allowing them to work free during normal rotation. The Hanksugi HS68's stone grip protection system is specifically engineered for this purpose, using groove geometry that prevents stone retention while maintaining the open channel flow needed for self-cleaning. Fleet operators who skip this specification often discover the cost of casing damage far exceeds the savings from choosing a less-capable tire. You can compare open shoulder tire specs using our cost per mile calculator.
Hanksugi manufactures three open shoulder drive tire models, each engineered for specific operating conditions and regional markets. All three feature aggressive tread patterns with self-cleaning groove geometry, stone ejection protection, and durable casings designed for retreadability.
Stone grip protection with crack and tear resistance. Wide tread design with four decoupling grooves for even weight distribution and reduced irregular wear.
Advanced cut-and-chip resistant compound with rugged construction for on/off road mixed-use applications. Built for construction, logging, and severe service environments.
HATT 3+1 compound technology delivers lower cost per kilometer with superior rolling resistance and fuel savings. Engineered for Latin American highway conditions.
The choice between open and closed shoulder drive tires depends on your primary operating conditions. Neither design is universally superior; each is optimized for different duty cycles. The table below summarizes the key differences to help you make the right decision for your fleet. For a detailed guide, read our complete comparison of closed shoulder vs. open shoulder drive tires.
| Characteristic | 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 |
| Wet Weather Performance | Superior -- wide lateral grooves evacuate water quickly | Good -- narrower channels adequate for highway rain |
| Highway Fuel Economy | Moderate -- higher void ratio increases rolling resistance slightly | Excellent -- continuous shoulder reduces friction and fuel consumption |
| Tread Life on Highway | Good -- separated blocks may wear faster at sustained highway speeds | Excellent -- even pressure distribution maximizes mileage |
| Self-Cleaning Ability | Excellent -- debris ejects naturally through open channels | Limited -- closed edges trap material more readily |
| Noise Level | Higher -- more air passing through open grooves creates road noise | Lower -- continuous shoulder reduces noise at highway speeds |
| Best Application | Regional, mixed service, on/off highway, construction | Long-haul OTR, interstate highway, high-mileage routes |
| Hanksugi Models | HS68, HS84, HS28+ Titan Trax | HS88, HS58 |
The table below lists every size available across Hanksugi's open shoulder drive tire lineup. Click any size to view detailed specifications, load ratings, and compatible models on the dedicated size page.
| Tire Size | Model | Ply Rating | Tread Depth | Application | Market |
|---|---|---|---|---|---|
| 11R22.5 | HS68 | 16 PR | 20.6 mm | Regional / Long Distance | LATAM |
| 295/75R22.5 | HS68 | 14 PR | 20.6 mm | Regional / Long Distance | LATAM |
| 11R24.5 | HS68 | 16 PR | 20.6 mm | Regional / Long Distance | LATAM |
| 285/75R24.5 | HS68 | 14 PR | 20.6 mm | Regional / Long Distance | LATAM |
| 11R22.5 | HS84 | 16 PR | 19/32nds | Mixed Service / On-Off Road | USA |
| 11R24.5 | HS84 | 16 PR | 19/32nds | Mixed Service / On-Off Road | USA |
| 295/80R22.5 | HS28+ Titan Trax | 18 PR | 22 mm | Highway Traction | LATAM |
Need help choosing the right size? Use our tire cost calculator to compare cost per mile across sizes and models, or contact our team for a fleet consultation.