Both are categorized as all-terrain tires from different brands. Both have an open tread design with wide shoulder spaces and central channels to provide them with excellent off-road traction balanced with exceptional on-road performance.
M55 highlights an open shoulder and aggressive tread block design which allows it to be rated as a 3 Peak Mountain Snowflake (3PMSF) tire. Its tread is pinned to provide a strong grip on ice and is crowded with deep moulded sipes for water evacuation. Its aggressive lug layout enhances its handling and traction on rough surfaces. Moreover, it features Toyo tread composition with a cut and chip resistant compound which promotes its tread life.
ST Maxx also features an open shoulder design having aggressive central and lateral tread. However, this tire is not rated as 3PMSF but its composition is stronger and the tread is more durable. Its tread has undergone Armor Tek3® construction which enhances its strength and stability. Its tread is also rich with numerous sipes for water evacuation and grooves contain stone ejectors. Also, stud holes are present for extra grip on ice.
Table of Contents
Side By Side Comparison
Toyo M55
Cooper Discoverer ST Maxx
| Specifications | M55 | ST Maxx |
| Tire Type | All-Terrain | All-Terrain |
| Tested Size | LT265/70R18 | LT265/70R18 |
| Tread Depth | 18.3/32” | 18.5/32” |
| Section Width | 10.6” | 10.7” |
| Diameter | 33” | 32.87” |
| Rim Range | 7 – 9” | 7 – 9” |
| Max. Inflation Pressure | 80 psi | 80 psi |
| Max. Load | 3525 lbs | 3525 lbs |
| Tire Weight | 57 lbs | 58 lbs |
| Revs/Mile | 629 | 632 |
| Price | 300 – 310$ | 340 – 350$ |
Comparing Toyo M55 VS Cooper ST Maxx
M55 is an all-terrain tire provided with an asymmetric tread design and open shoulders. Its aggressive block tread design promotes its handling and grip. However, its shoulders are comparatively less wide but are pinned for studs, giving excellent traction on ice. Its tread is provided with moulded sipes for water evacuation. Its tread depth is slightly less compared to its peer but features wider central channels for better traction on snow and mud. Its 3PMSF and M+S rating ensure its exceptional performance on rugged paths. Moreover, Toyo and spike rubber with cut and chip resistant compound are included in its composition.
ST Maxx is also an all-terrain tire which highlights an asymmetric tread design. Its shoulders are also opened and are provided with stud holes for excellent grip on icy roads. Its shoulder grooves are broader which grants it better traction on ice. For water evacuation, its tread is equipped with moulded and rectilinear sipes. It is not counted as a 3PMSF rated tire but can be trusted on snowy and muddy paths due to its deeper tread and wider shoulder grooves. It features a strong Armor Tek3® composition with chip and cut resistant compound which promotes its durability and tread life.
On-Road Comparison
- Dry
M55 offers slightly wider central grooves which lower its tread contact and reduce its traction on dry roads. However, its comparatively constricted shoulder blocks allow slightly better handling on dry paths.
ST Maxx offers a comparatively greater contact patch which promotes its grip on dry paths but its broader shoulder channels reduce its tread contact from the shoulders side which slightly reduces its steering management efficacy.
| Dry Traction | M55 | ST Maxx |
| Dry Grip | Moderate | High |
| Dry Handling | High | Moderate |
- Wet
Although, M55 is provided with highly efficient 3D moulded sipes for water evacuation, its lower contact patch reduces its traction on wet surfaces. However, its comparatively constricted shoulder blocks with moulded sipes allow better steering management and enhance its aquaplaning resistance.
ST Maxx features rectilinear sipes as well in addition to moulded sipes on its confined central tread blocks which allow it to offer a stronger grip and better hydroplaning resistance on wet surfaces. However, it is second to its peer in the case of handling on wet paths due to the comparatively lower contact patch of its shoulder blocks.
| Wet Traction | M55 | ST Maxx |
| Wet Grip | Moderate | High |
| Wet Handling | High | Moderate |
| Aquaplaning Resistance | Moderate | Moderate |
Off-Road Traction
- On Muddy Surfaces
M55 has a bit lower tread depth as compared to its peer but it has wider central grooves which give it more space to bite the mud and throw it backwards, to promote its grip and allow smoother navigation on mud. But it has closely packed shoulder blocks as compared to that of its rival which makes it difficult to handle while cornering.
ST Maxx offers a comparatively deeper tread which promotes its traction on mud but its leaner grooves are not much efficient in biting mud and throwing it backwards, to enhance its grip on mud. However, it is more stable while cornering as it has comparatively broader shoulder grooves.
| Mud Traction | M55 | ST Maxx |
| Mud Grip | High | Moderate |
| Mud Handling | Moderate | High |
- On Snowy Surfaces
Some sizes of M55 are 3PMSF rated as it gives outstanding performance on soft snow and is also capable of bearing extreme snowy conditions. It has comparatively wider central channels which are highly efficient in making a strong grip on snowy paths. However, its comparatively constricted shoulder blocks reduce its stability while cornering.
ST Maxx is not a 3PMSF rated tire but stands as M+S rated. However, it stands second to its counterpart in providing stronger traction on snowy paths as it has comparatively thinner central grooves which are not much efficient in grabbing and throwing back soft snow to promote its navigation. However, it gives better steering management while cornering due to its broader shoulder grooves which grant it more prominent biting edges.
| Snow Traction | M55 | ST Maxx |
| 3PMSFR | Yes | No |
| Snow Grip | High | Moderate |
| Snow Handling | Moderate | High |
- On Icy Surfaces
M55 leads many other tires in the case of grip over icy paths but it is second to its counterpart. It has a comparatively lower contact patch which reduces its traction on ice. However, it provides better handling over ice as its shoulder tread is pinned for studs and has comparatively constricted shoulder blocks.
ST Maxx is dominant over its peer in the case of ice grip as it has an overall greater contact patch which awards it a stronger grip on ice. Its shoulder tread is also pinned for excellent stability over ice but its shoulder tread contact is comparatively lower which places it second to its peer in the case of steering response on icy surfaces.
| Icy Traction | M55 | ST Maxx |
| Ice Grip | Moderate | High |
| Ice Handling | High | Moderate |
- On Rocky Surfaces
M55 is provided with an aggressive tread block design which allows it to cope with rough rocky conditions. Although, it lacks stone ejectors and has shallower grooves and constricted shoulders its wider central grooves promote its traction over rocks up to some extent. However, it is unable to beat its counterpart in providing stability over the rocks, while taking turns.
However, ST Max has comparatively constricted central tread blocks which results in reducing its grip over rocks but it has broader shoulder grooves which are provided with highly efficient stone ejectors. Moreover, it has a comparatively deeper tread which awards it an excellent performance and stability over the rocks.
| Rock Traction | M55 | ST Max |
| Rock Grip | High | High |
| Rock Handling | High | Moderate |
| Stone Ejectors | Absent | Present |
Comparison of Noise and Comfort
M55 is comparatively uncomfortable and noisier on paved paths. Its tread channels are wider which catches more air particles into them. As the tire rolls, this squeezed air rushes out and produces noise thus reducing the comfort level of the tire. However, the same wider channels are proved functional in absorbing jerky effects during off-roading. So it is a more comfortable tire on rugged surfaces.
ST Maxx is smoother, quieter and more comfortable on paved paths. Its grooves are comparatively leaner which trap less air in them, producing lesser noise when it is rushed out. So, this tire gives you a more comfortable on-road journey. However, its leaner channels are less profitable in absorbing jerks, so it lacks in providing a comfortable ride on rugged paths.
| Noise and Comfort | M55 | ST Maxx |
| On-Road Noise | Moderate | Less |
| On-Road Comfort | Moderate | High |
| Off-Road Noise | Less | Moderate |
| Off-Road Comfort | High | Moderate |
Tread Compound and Structure Comparison
M55 features Toyo tread composition with a spike rubber blend. A cut and chip resistant compound is also introduced in its composition. It has a single central tread block row. Its central tread channels are wider whereas shoulder channels are constricted from one end. Its shoulder tread is pinned for studs. Moreover, all of its tread blocks feature 3D moulded sipes.
ST Pro is equipped with Armor Tek3® composition with silica and natural rubber compound which is cut and chip resistant. It also has a single central tread block row with irregularly placed tread blocks. Its central tread channels are leaner whereas shoulder grooves are widely opened. Its shoulder tread is also pinned. Moreover, its tread blocks offer 90% moulded and 10% rectilinear sipes.
| Composition and Structure | M55 | ST Maxx |
| Tread Composition | Toyo Compound | Armor Tek3® Compound |
| Tread Design | Asymmetric | Asymmetric |
| Central Ribs | One | One |
| Sipes | Moulded | Moulded / Rectilinear |
| Central Grooves | Wider | Leaner |
| Shoulder Channels | Opened | Widely Opened |
Treadwear and Durability
M55 has a slightly lesser contact patch with the ground which reduces its rolling resistance and treadwear but its tread channels are a bit shallower as compared to its counterpart which results in faster tread consumption. Also, its weaker tread composition results in lower tread life and less durability.
ST Max, however, offers higher rolling resistance but its tread is slightly deeper and offers more time to get consumed. So, it offers a longer tread life. Moreover, its Armor Tek3® construction is comparatively much stronger which adds to its durability.
| Durability | M55 | ST Maxx |
| Treadwear Warranty | 45,000 miles | 60,000 miles |
| Workmanship Warranty | 3.3 years | 5 years |
Quick Summary
M55:
- Gives a better performance on snow and mud.
- Is more comfortable for off-roading.
ST Maxx:
- Gives better performance on dry, wet, icy and rocky paths.
- Is more comfortable on paved paths.
- Offers longer tread life and is more durable.
- Features a stronger tread composition.
