The Cooper Discoverer Road Trail AT and its predecessor, the Discoverer AT3 4S, are both on-road oriented all-terrain tires. They offer good traction in mild off-road conditions without compromising on-road performance, comfort, and all-weather traction. So, is the newer tire any better? You’re about to find out.
Table of Contents
Info on Sizes
Let’s start with the Road + Trail tire.
So this tire comes in 36 sizes, ranging from 15 to 22 inches, making it suitable for a variety of SUVs, mid-size, and light-duty pickup trucks. Its sizes have following specs.
- Speed ratings: T, H and V.
- Load ratings: SL and XL only, (LT sizes not available as of now).
- Tread depth: 11, 12 and 13/32″.
- UTQG: 620 A B.
- Treadwear warranty: 65k miles.
- All sizes have 3 Peak ratings, along with M+S.
Detailed Review of Discoverer Road+Trail tire: https://tiredriver.com/cooper-discoverer-road-trail-at-review/
On the other hand, the predecessor, the Cooper Discoverer AT3 4S comes with 42 sizes in total (15″ to 22″ rim sizes).
And this tire has following specs.
- Load range: SL and XL
- Speed ratings: T and H
- Weight range: 31 to 45 lbs
- Tread depth range: 12.5 to 14/32″
- All sizes have 3PMSF ratings
- Warranty: 65k miles
Detailed Review of Discoverer AT3 4S tire: https://tiredriver.com/cooper-at3-4s-review/
Dry Performance
When assessing the on-road performance of a tire, dry traction and handling emerge as pivotal components.
Now overall, the Cooper Discoverer Road+Trail AT stands out for its enhanced capabilities in these areas, building upon the foundation laid by its predecessor, the AT3 4S.
Dry Traction | A Closer Look
Dry traction is crucial for ensuring safe and effective vehicle control and can be segmented into two main areas: directional grip and lateral traction.
Let’s start with directional.
Directional Grip
This aspect of traction is primarily evaluated through braking tests, where the rubber’s contact with the road, tread composition, and weight significantly influence performance.
Now the Road+Trail AT demonstrates superior directional grip, aided by a central rib design that creates a more continuous path for contact and is fortified by a stickier rubber composition.
This design not only enhances the grip but also contributes to shorter braking distances in standardized tests, such as from 60 to 0 mph.
Lateral Traction
The ability of a tire to maintain grip during lateral movements, such as during turns, is equally important.
And here the Cooper Discoverer Road+Trail AT again is taking the lead, thanks to an improved shoulder design that features optimized biters and chamfered edges.
These modifications allow for increased lateral grip, which is evident from enhanced g-force readings during cornering tests.
Overall Handling
Combining the elements of lateral grip and steering responsiveness, the overall handling of the Road+Trail AT marks a significant improvement over its predecessor.
The tire’s enhanced shoulder design contributes to greater lateral traction and better steering response. However, despite these advancements, there remains room for improvement, particularly in steering feedback.
The tire exhibits a slight delay in response and a tendency to understeer, attributed to its significant weight which impacts the flexibility of the lugs, affecting steering clarity, especially during mid-corner maneuvers.
Noise Reduction
Noise in tires primarily emanates from the interaction of air with the tire’s structure. Air compression within the tire and its subsequent contact with tread walls produces various undesirable noises such as in-groove resonance and tread vibrato.
Although both tire models address this concern, the Cooper AT3 4S excels in mitigating it more effectively.
Particularly noteworthy are the AT3 4S’s shoulder blocks. These blocks are densely packed and feature thick ridges that obstruct the lateral grooves between the lugs.
Cooper employs what it calls “Whisper Grooves Technology” in this design, which significantly restricts airflow at the outset.
And this tech is basically better on AT34s.
Additionally, the AT3 4S generates less rumbling due to its less aggressive tread design and features improved pitch sequencing compared to the Road+Trail tire.
Pitch sequencing is a design strategy that arranges lugs to transform noise into various tones, attempting to cancel out the frequencies of each other.
Wet Traction
Effective water clearance from the tread is crucial for maintaining grip on wet surfaces. This is largely achieved through the tire’s grooves and sipes.
Grooves play a major role in displacing water and providing resistance against hydroplaning.
Now here, the Cooper Road+Trail AT excels in this area, equipped with a substantial number of grooves, akin to its competitors.
The challenge intensifies at a micro level, which is where many all-terrain tires falter. However, the Discoverer Road+Trail breaks the mold by delivering superior performance in wet braking, handling, and steering responsiveness.
This is attributed to its mix of linear and wave-like sipes, coupled with numerous biting edges. These sipes, though seemingly simple slits, serve as reservoirs that collect water forced into them under tire pressure, then expel it as the tire rolls.
With its varied shapes and angles of sipes, the Cooper Road+Trail demonstrates exceptional ability to disperse water in all directions, offering enhanced wet traction compared to its predecessor, the well-regarded Cooper AT3 4S. Nonetheless, there is a slight room for improvement in reducing over-steering at the limits.
Enhancing the tire’s feedback could significantly boost its overall performance in wet conditions.
Mud Performance
The performance of a tire in muddy conditions hinges significantly on its tread design, particularly the size of its grooves. Larger tread voids correlate with a higher rate of mud expulsion. If the voids are too narrow, mud can accumulate quickly, causing a loss of traction.
While none of the Discoverer tires are ideal for deep muddy terrains, the Cooper Road+Trail is a more viable option. It features staggered shoulders and structured sidewalls that aid in mud traction by scooping and displacing mud backward, thereby facilitating forward movement.
Despite having a closed-up lug design, the Cooper Road+Trail still maintains interconnected grooves that traverse in all directions, enhancing the tire’s self-cleaning capabilities and improving grip on lighter mud.
Conversely, the Cooper AT3 4S falls short primarily due to its smaller sidewall lugs, which diminish its ability to paddle through mud effectively. This limitation hinders its capacity to throw back mud to create forward momentum, a feature more pronounced in its successor.
Traction on Rocks
Navigating rocky terrains involves two distinct challenges: rock climbing and maintaining traction on gravelly or dirt-filled roads.
For rock climbing, tires need to provide strong grip in all directions to prevent the vehicle from overturning in severe situations.
Among the two tire models, the Cooper Discoverer Road+Trail is superior for such terrain. It offers enhanced biting abilities at multiple angles.
The central interlocked section of the tire provides the bulk of the directional traction. Meanwhile, its shoulders feature more aggressive designs with chamfered edges and numerous offsets.
These elements, along with thicker sidewall lugs, contribute to lateral traction, which is particularly effective when the tire is under reduced air pressure.
Sand Traction
Successful sand driving hinges on reducing tire air pressure to increase the tire’s footprint on the sand. However, other factors such as weight and sidewall characteristics also influence performance. The Cooper Discoverer Road+Trail excels in sand due to its design.
Specifically, the Road+Trail expands its sidewall lugs when the air pressure is lowered, enhancing its overall footprint and interaction with sand. In contrast, the Discoverer AT3 4S, despite having a softer compound that molds well with sand, features sharper sides which are more susceptible to sinking—a critical drawback as digging deeply into the sand reduces traction significantly.
Fuel Consumption
Fuel efficiency in tires is closely linked to their rolling resistance. The Cooper Discoverer could see improvements in this area.
This model incorporates the EnduraGuard Design, aimed at providing a durable internal construction.
However, this design also increases the tire’s weight, which adversely affects fuel efficiency, particularly when compared to the lighter AT3 4S.
So the heavier Road+Trail requires more energy to rotate.
Additionally, the tire’s composition, optimized for winter and wet conditions, employs a pliant rubber compound. This flexibility causes the tire lugs to bend more under load, dissipating energy primarily as heat rather than conserving it for rolling.
This process leads to increased fuel consumption. While these design elements enhance durability and performance under specific conditions, they slightly reduce fuel efficiency.
Winter Traction
Both tires are equipped with the 3-peak mountain snowflake and M+S ratings, signifying their capability in winter conditions. However, there are differences in their performance in such settings.
The Cooper Discoverer Road+Trail demonstrates superior winter performance, particularly in terms of directional grip.
This is due to its effective snow-to-snow contact facilitated by the strategically placed snow vices on the central lugs.
These saw-toothed edges, pointing in both lateral and longitudinal directions, capture and retain more snow, enhancing traction by utilizing the natural tendency of snowflakes to stick together.
While both tires perform comparably on icy surfaces, the Road+Trail’s design provides a tangible advantage in snowy conditions, offering better grip due to its unique tread features.
Conclusion
In conclusion, the Cooper Discoverer Road+Trail AT demonstrates comprehensive strengths across various performance metrics, excelling in dry traction, handling, and lateral grip due to its innovative tread design and enhanced rubber composition.
While it outperforms in scenarios such as mud and sand traction by leveraging larger tread voids and expanded sidewall lugs, it still holds areas for improvement in fuel efficiency due to its increased weight and the flexible nature of its rubber compound that affects rolling resistance.
Additionally, it shows superior winter traction capabilities, significantly aiding in snow-to-snow contact and traction, making it a robust option despite slight understeer tendencies and room for refinement in steering feedback.
These attributes make the Road+Trail a versatile and effective tire for diverse driving conditions, although it may benefit from enhancements in specific areas like fuel consumption and steering precision.
