Forum Discussion
Lantley
May 02, 2014Nomad
fla-gypsy wrote:PartyMarty wrote:
regarding weight reduction with LT tires ?
That is the misunderstanding .
The ST scale is so weak that the placard on the side of equivalent size tires shows the ST tire at a higher weight rating than the similar sized LT tire .
even though the LT tire is more tire from the same manufacuter.
The LT Tire definitely is more tire than than the same size ST tire .
from the tire rack website here is a comparison between ( nearly ) identical 235/80R16E tires :
From the tirerack website .
Goodyear ST 235/80 R 16 E
price = $ 135 each
weight = 34 # each
section width is 9.2 "
tread width= 6.8 "
diameter is 30.7 "
rated 3420 # at 80 psi on ST scale
Goodyear LT 235/85 R 16 E
price = $ 157 each
weight = 50 # each
section width is 9.3 "
tread width= 7.0 "
diameter is 31.7 "
rated 3042 # at 80 psi on LT scale
So the Goodyear ST tire is rated for 112.4 % higher load rating than the equivalent Goodyear LT tire .
And they will sell this ST tire for only 86 % of the LT tire .
And the ST tire has less mass for cordage , plys , caps and so forth because it weighs 76 % of the Goodyear LT tire .
This is very telling as to how much lower the ST standards are in relation to the LT standards .
Further the ST tire has plainly stamped on the sidewall " for trailer use only " .
The LT tire has no disclaimer .
to recap :
the manufacturer is the same.
both tires are 235 ( one is 80 = 80% and the other is 85 = 85% )
both tires are load range E or 80 PSI .
The ST tire is cheaper ( 86% cost ) .
The ST tire has less rubber and cords .
The ST tire weighs 76 % of the LT Tire .
The LT tire only gets a 3042# rating on the LT scale .
The cheaper / lighter ST tire gets a 3402 # rating on the less demanding ST scale .
This is very clear .
Goodyear , the manufacturer , has to build a much tougher tire for LT use such as on our heavy duty pickups .
If what you say is true then why do they derate the tire? Couldn't there be specific design differences that account for a higher weight rating? Why would they derate a tire that is capable of more weight? I have heard this argument before but other than a weight difference in the two tires I see no reason to believe it can carry more then the maker says it can.
I think they derate the tire because it is designed to carry live passengers. They derate the tire to ensure it won't fail. The tire is not rated to tow at it's max limit. There are more tolerances built in to avoid failure
ST tires on the other hand are not designed or rated to carry passengers. St tires have to meet a lower quality standard. In theory if and when they fail there are no human lives at risk.
Consequently ST tires fail all the time especially when used at there limits. Likewise LT tires have less failures even when used at their limits
How can a physically lighter ST tire carry more weight than the heavier LT tire? Simple the standards are not the same. The ST tire is designed to a lower threshold and quality standard because it is not rated as a passenger carrying tire.
About RV Tips & Tricks
Looking for advice before your next adventure? Look no further.25,103 PostsLatest Activity: Jan 21, 2025