What does TPI mean for bicycle tires?
T.P.I. is the acronym of Threads Per Inch, which refers to 2.54 cm in the imperial system for bicycle tires.
By means of TPI we can measure how many threads there are in a casing by counting the number of threads per inch.
Some casings are made of 2 layers of threads and others of 3 layers depending on how they are designed; all Veloflex casings have 2 layers to ensure greatest flexibility and performance.
320 TPI casings are the strongest we produce, whereas 350 TPI ones (Race models) are more suitable for bicycle racing as more threads per inch means reducing the section of each thread to obtain a lighter and more flexible casing.
A 320 TPI casing with 2 layers will be more flexible and lighter than a three-layer 360TPI casing:
320/2 = 160 threads per layer
360/3 = 120 threads per layer
which means that the threads used in a three-layer casing have a larger section and so overlapping three layers made of larger threads will make the casing less flexible and less high-performance than a 2-layer casing made of smaller threads.