10PR — Load Range E
E
Ply rating — casing strength, not a count of plies10-ply rating
An equivalence, not a count: a modern radial at load range E is built to carry what a 10-ply cross-ply once did, with far fewer actual plies. The usual load range for a full-size pickup or 4x4 LT tyre.
Standardised by ETRTO or TRA.