Why do bicycle handles made of TPU granules remain flexible and brittle in low temperatures?
Publish Time: 2026-01-06
Many riders have experienced an unpleasant detail when cycling in the cold mornings or at high altitudes: traditional rubber or low-quality plastic bicycle handles become stiff and brittle, even making a "crackling" sound when gripped tightly. Not only do they feel cold and hard, but they also severely weaken handling stability and shock absorption. However, high-end bicycle handles made of thermoplastic polyurethane (TPU) granules maintain their softness, elasticity, and grip even in sub-zero temperatures—this characteristic is not accidental, but stems from the unique molecular structure and physical properties of TPU material, making it a crucial guarantee for riding safety and comfort in extreme climates.TPU belongs to a class of high-performance thermoplastic elastomers that combine the elasticity of rubber with the processability of plastics. Its molecular chains consist of alternating hard and soft segments: the hard segments provide strength, abrasion resistance, and high-temperature stability, while the soft segments give the material excellent flexibility and low-temperature ductility. In low-temperature environments, ordinary rubber or PVC materials harden and become brittle due to a sharp decrease in molecular chain mobility, forming microcracks at the microscopic level and exhibiting loss of elasticity and brittleness at the macroscopic level. However, the soft segments in TPU (usually polyether or polyester polyol) have extremely low glass transition temperatures (Tg). Even in frigid conditions, these molecular segments maintain sufficient freedom of movement, keeping the material soft and resistant to brittle fracture.Particularly noteworthy is the superior low-temperature performance of polyether-based TPU. Compared to polyester-based TPU, polyether segments are less sensitive to hydrolysis and low-temperature environments, and have weaker intermolecular forces. Therefore, they better maintain resilience and a smooth feel in cold climates. This means that even on frosty mornings or in snowy high-altitude areas, TPU handles still conform to the curves of the hand, providing stable friction and cushioning, preventing slippage or increased vibration transmission caused by material hardening.Furthermore, TPU material itself possesses high cohesive strength and excellent tear resistance. Even at low temperatures, its surface maintains excellent integrity and will not crack due to repeated bending or impact. This "soft yet resilient, tough yet brittle" characteristic ensures consistent performance during long-term outdoor use, whether exposed to scorching heat or freezing cold, significantly extending its lifespan.From a manufacturing perspective, high-quality TPU particles are directly bonded to a metal or composite core tube through precision injection molding or overmolding, eliminating the need for adhesives and avoiding peeling issues caused by adhesive failure at low temperatures. The one-piece molding structure also ensures that surface textures (such as anti-slip grooves or honeycomb patterns) remain clear and effective at low temperatures, further enhancing grip safety when hands are wet or wearing gloves.More importantly, this low-temperature flexibility directly translates into a substantial improvement in the riding experience. The hands are the extremities of the body and are extremely sensitive to cold. A consistently soft, slightly warm handle not only reduces numbness caused by heat loss but also effectively absorbs high-frequency vibrations from the road surface, preventing cycling fatigue symptoms such as "hand numbness" or "white finger syndrome." On downhill slopes with sudden braking or on gravel roads, a stable grip is crucial for precise control—safety often hinges on that precise grip.In summary, the reason TPU particles allow bicycle handle bars to remain flexible and resistant to brittleness at low temperatures is due to their scientific molecular design, excellent chain segment movement capabilities, and reliable structural integrity. It's not just an advancement in materials technology, but also a profound response to the real needs of riders. When the cold wind howls and your hands grip the handlebars tightly, that consistent softness and reliability is the warmest protection that technology provides for winter riding.
