[A/S] Trailer tires

["Tom Patterson" <pattersontom@xxxxxxxxxxxxxx>]

Hunter,
     It looks like the Load Ranges are related to air pressure, rather 
than load carrying capacity.  That is, a certain load range designates 
the tire air pressure at which the maximum load carrying capacity for a 
given tire is reached, rather than the load capacity itself.  For the 
carrying capacity, you apparently have to use the load rating index.  
Here is an excerpt from http://www.tirerack.com/ which 
explains how it works.
I don't know how the tables will look when Yahoo strips off the HTML.
     Also, for this search information, I used the iLOR search engine 
(http://www.ilor.com/).  Those who 
haven't tried this engine, which is based on Google will probably like 
the capabilities.

-Tom 


Maximum Load
A tire's maximum load is the most weight the tire is designed to carry. 
Since a tire's load carrying capacity is related to the tire's size and 
how much inflation pressure is actually used, maximum loads are rated 
with the tire inflated to an industry assigned inflation pressure.

Additionally, load ranges are used to separate tires that share the same 
physical size, but differ in strength due to their internal 
construction. "Higher" load ranges are used to identify tires that have 
a stronger internal construction, and therefore can hold more air 
pressure and carry more weight.

Each load range has a assigned air pressure identified in pounds per 
square inch (psi) at which the tire's maximum load is rated. Listed 
below are the air pressures at which maximum load is rated for popular 
P-metric and LT tires:

      Tire Load Ranges Inflation Pressure Assigned
      For "Maximum Load" Ratings
     
      P-metric 
      Standard Load (SL) 35 psi 
      Extra Load (XL) 41 psi 
      Light Truck 
      Load Range C (LRC) 50 psi 
      Load Range D (LRD) 65 psi 
      Load Range E (LRE) 80 psi 

P-metric tires used on passenger cars and station wagons are rated to 
carry 100% of the load indicated on the tire's sidewall (or listed for 
the tire in industry load/inflation charts). However, if the same 
P-metric tires are used on light trucks, (pickup trucks and sport 
utility vehicles for example), their carrying capacity is reduced to 91% 
of the load indicated on the tire's sidewall. This reduction in load 
results in causing light truck vehicle manufacturers to select 
proportionately larger P-metric sized tires for their vehicles to help 
offset the forces and loads resulting from a light truck's higher center 
of gravity and increased possibility of being occasionally "overloaded."


For example, P235/75R15 P-metric sized, standard load tires used on cars 
and light trucks would be rated to carry the following maximum loads at 
35 psi:

      Cars Full Value 2028 lbs. 
      Light Trucks 9% Reduced Value 1845 lbs.