The letter codes are going away, as they are confusing to many...going
to the number codes for load rating
Letter codes signify the number of cotton plys (fabric embedded in the
tire sidewall) and is very old. 'C' signifies 6 plys. 'D' signifies 8 plys
'E' signifies 10 plys
Today, cotton plys are no more and synthetic cords to make up the fabric
Most today only have 1 - 2 actual plys or more, but can be rated 'E'
(10 ply)
Also needs the tire size in order to know it's ratings. A 10 ply (E)
small tire will NOT have the same rating as a 10 ply (E) bigger tire
This is the best tire/wheel/etc info site all in one that is easy to
understand. Read up and then the other sites will make more sense
Best Tire info site found to date