Tire Cross Section Analysis : Michelin Primacy 4 ST vs Continental UltraContact 7–> This article offers a detailed exploration into the construction of two notable tire models, following our Top Tire Review’s comprehensive touring test in the Asia-Pacific (APAC) region. It seeks to reveal the design and construction secrets of the Michelin Primacy 4 ST and the Continental UltraContact 7. Through a thorough examination of the cross sections of these tires, the article sheds light on the various materials, structural differences, and engineering techniques that contribute to their performance, durability, and adaptability to various road conditions.
This analysis is highly informative for automotive enthusiasts, tire industry professionals, and consumers interested in a deeper understanding of these tires’ unique features. For a more detailed view, a full-resolution cross-section image of each tire is available at the conclusion of the article, providing a visual complement to the textual analysis.
Table of Contents
Results: Tire Cross Section Analysis
| Body ply | Bead | Capply | Under Tread Gauge (UTG) | |
| Michelin Primacy 4 ST | 2+0 | 5×5 | 212 hybrid | 3.2mm |
| Continental UltraContact 7 | 1+0 | 5×4 | 222 | 3mm |
Body Ply:
The Michelin Primacy 4 ST utilizes a “2+0” body ply configuration, indicating two layers of ply with no additional reinforcement. In contrast, the Continental UltraContact 7 employs a “1+0” configuration, suggesting a single ply layer. The additional ply in the Michelin contributes to enhanced durability and stability, especially under heavy loads or high-speed conditions.
Bead:
The bead construction in both the Michelin Primacy 4 ST and Continental UltraContact 7 is quite similar, with the Michelin having a “5×5” and the Continental a “5×4” configuration. Given the bead’s vital role in ensuring the tire’s structural integrity and proper fit on the rim, these slight differences are not expected to confer a significant advantage to either tire. While Michelin’s slightly denser bead might offer a marginal improvement in rim seating and air retention, this difference is minimal. Additionally, the Continental’s bead configuration could potentially lead to a lower manufacturing cost without compromising on essential performance aspects.
Cap Ply:
The construction of the cap ply is crucial in determining a tire’s high-speed capabilities. The Continental UltraContact 7 utilizes a 222 cap ply, which is standard for a tire with a W speed rating, capable of handling speeds up to 270 km/h (168 mph). Interestingly, Michelin has opted for a hybrid 212 cap ply in the Primacy 4 ST. This choice is quite innovative, as a 212 cap ply typically offers superior high-speed performance compared to a 222. The hybrid nature of Michelin’s cap ply, combining different materials, should theoretically enable even higher speed capabilities at a reduced cost. However, there’s a caveat; if not executed precisely, the 212 cap ply could lead to issues like uneven wear, which needs careful consideration in its design and manufacturing.
Under Tread Gauge (UTG):
The Michelin Primacy 4 ST has an UTG of 3.2mm, slightly thicker than Continental’s 3mm. UTG refers to the thickness of the material under the tread. A thicker UTG in the Michelin might offer better protection against punctures and impacts, contributing to a longer tread life, whereas Continental’s slightly thinner UTG could potentially enhance fuel efficiency and reduce the tire’s overall weight.
Tread depth:
| Tread depth, mm | 1 | 2 | 3 | 4 | Average |
| Michelin Primacy 4 ST | 6.48 | 7.16 | 7 | 6.64 | 6.82 |
| Continental UltraContact UC7 | 7.41 | 7.53 | 7.3 | 7 | 7.31 |
Tread depth is a critical factor in tire performance, influencing wear, aquaplaning resistance, handling, and rolling resistance. The tread depth measurements for the Michelin Primacy 4 ST and Continental UltraContact UC7 highlight some trade-offs between these two models.
Michelin Primacy 4 ST has an average of 6.82 mm. In comparison, the Continental UltraContact UC7 has an average measured tread depth of 7.31 mm.
A deeper tread depth, as seen in the Continental, typically offers better protection against aquaplaning and may provide enhanced grip and handling, especially in wet conditions. However, deeper grooves can also increase rolling resistance, which can impact fuel efficiency and produce more noise.
On the other hand, the Michelin’s shallower tread depth might result in slightly lower rolling resistance, potentially offering better fuel efficiency and a quieter ride. However, the trade-off is usually a reduced ability to resist aquaplaning and potentially a shorter lifespan due to quicker tread wear.
Conclusion
The Michelin Primacy 4 ST, with its 2+0 body ply configuration, hybrid 212 cap ply, and slightly shallower tread depths, appears to be designed for enhanced durability and stability, potentially offering better high-speed capabilities and a balanced performance in terms of fuel efficiency and noise levels. The unique hybrid cap ply could be a game-changer in terms of high-speed performance, though it requires precise execution to avoid issues like uneven wear.
On the other hand, the Continental UltraContact 7, featuring a 1+0 body ply and a standard 222 cap ply, along with deeper tread depths, seems to prioritize aquaplaning resistance and wet grip. The deeper treads could mean better handling in wet conditions but might result in higher rolling resistance.
These differences reflect each brand’s approach to tire design, balancing aspects like speed capability, durability, and efficiency to meet diverse consumer needs and driving conditions.
For a more detailed visual understanding of these comparisons, high-resolution cross-section images of both tires are available for download at the links provided at the end of the article. These images offer a closer look at the structural nuances and help in appreciating the sophisticated engineering behind each tire model.
High-Resolution cross-section images:
