Decode load range letters B–N into ply ratings and tell SL apart from XL (reinforced) sidewall marks. Free lookup for LT and passenger tires, no signup.
Letters B–N map to ply rating. SL and XL are inflation marks, not ply counts.
E
Marking
Load range letter
Classification
10
Ply rating
Ply rating is a capacity class — modern radials rarely have that many physical plies.
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Enter C, D, E, F, and the rest of the letter scale (B–N, skipping I and K). You get the conventional ply rating (C = 6-ply, E = 10-ply, and so on) used on LT, ST, and trailer tires. That letter is a load/inflation schedule, not a count of actual fabric plies in a modern radial.
Passenger tires often say SL or XL (or RF / Reinforced) instead of a C/D/E letter. The decoder classifies those marks: SL is standard load, XL is extra load — not a ply rating. That is the distinction people miss when they treat “XL” as “more plies.”
Notes in the workspace explain that a higher load range allows a higher maximum inflation and a higher load at that pressure. The tool does not print a single max-PSI number for every size — that still comes from the tire’s sidewall and the vehicle placard.
No account and no upload. You are mapping a sidewall letter to the standard classification, not sending a tire photo. Close the tab and the input is gone. For kilograms of capacity, use Load Index Lookup on the numeric index, not this letter.
On LT tires it is often Load Range E (or LRE). On P-metric tires look for SL, XL, or Extra Load / Reinforced.
B–N (without I or K) and SL/XL are accepted. RF or Reinforced is treated as XL.
Letter ranges show a ply rating (for example E = 10). SL/XL show that they are not ply ratings — they are load schedules.
Do not guess a max PSI from the letter alone. Set daily cold pressure from the vehicle sticker; the sidewall max is a limit.
Straight answers on privacy, limits, and how the workspace behaves.
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