Originally Posted By: FordFocus
My question is what does the "C" stand for in the size 195/70R15 C? Does it stand for Cargo? If so what does that mean. Is the tire constructed differently than a regular tire? The claims to be 8 ply with a max psi of 65 psi so it wouldn't mean that it is a 6 ply right?
http://www.tirerack.com/tires/tires.jsp?tireMake=Continental&tireModel=VancoFourSeason
Amateurs! Sheesh!
The "C" stands for "Commercial" ETRTO (European Tyre and Rim Technical Organization) uses the letter "C", where The Tire and Rim Association (TRA) - the US tire standardizing organization - uses the letters "LT". So you could say a "C" type type is equivalent to an "LT" type tire.
Yes, the tire is constructed quite different than standard passenger car tires (or should I say tyres?) of the same size. They are designed to operate at higher loads and higher inflation pressure than standard passenger car tires.
Unfortunately, ETRTO still uses the Ply Rating (PR) system - and, no, an 8 PR says nothing about what the actual construction (the number of plies in particular) - other than the tire is designed to operate under 8 PR conditions.
For example, a 295/70R22.5 Load Range G - a typical Medium Radial truck tire - has an rated inflation pressure of 110 psi. They typically have 5 plies - and only one ply of those is in the sidewall. It is made of a steel cable, but it is a single ply.
And to make things even more complex, only 2 of the 4 remaining plies (technically, they are belts) are actually used for load carrying purposes. The additional 2 plies are used for other purposes - one is a protector for the "working belt", and the other is a transitional ply to help better distribute the stresses. In theory, you could have a Load Range G (14 Ply Rating) with only 3 plies!
