What is the Difference Between a Bias Ply Tire and a Radial Tire and Can I Tell Date of Manufacture

Question:

whats the differance between a bias or radial tire ? i now have st215/75/r15 -C-LOAD loadstar shows only the d14-NO r14 ? also how do i determine the date the tire was mfg. Thanks

asked by: ernie c

Expert Reply:

The D14 will not fit your wheel if you currently have an R15 tire. That means your wheel is a 15 inch wheel and a D14 or R14 tire will fit a 14 inch wheel.

The difference between a bias ply and a radial tire is the way the rubber is layered. A bias ply is layered around the tire, and a radial tire is layered from sidewall to sidewall with steel belting. A radial tire will be more stable and will yield better ride quality.

Currently we do not have a 215/75-15 size tire. We do have a 225/75-15 that you could probably use. It will be 10mm wider and 15mm taller, so make sure your trailer could accommodate the larger size. We have 3 tires in this size, 2 of them are radial and 1 is bias ply. The bias ply is part # AM1ST96 and is load range D.

The radials are part # AM10256, load range D, and part # AM10251, load range C.

To check the date, read the last four digits of the DOT number. The DOT number is usually 12-15 digits long, combining numbers and letters. The last four digits indicate month and year of manufacture. For example, if the number ends in 1109, it was made in November of 2009.