Date: Wed, 5 Oct 2005 07:08:57 -0700
Reply-To: Larry Chase <roadguy@ROADHAUS.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Larry Chase <roadguy@ROADHAUS.COM>
Subject: Re: Vanagon Tire Guidelines Report - Are LT Tires really safer?
In-Reply-To: <20051005042357.726D6D809D@mx03.csee.siteprotect.com>
Content-Type: text/plain; charset="us-ascii"
Tim,
The goal with tire selection should be picking a tire that meets all
required specifications.
I don't care if it's a Passenger Car Tire a Light Truck Tire.
The problem is there are very few passenger car tires in 14" and 15"
formats, that meet the requirements for a Vanagon Tire.
Go to a 16" - 18" tire like many of the newer SUV's and you have a more
choices.
I know this wasn't your intention,
But posting information like this "Out of Context" could lead someone that
doesn't look at all the data, to misunderstand and make a very unsafe tire
decision.
To suggest that a Light Truck Tire is more unsafe than a Passenger Car Tire
when used on a Light Truck is very scary and your clip DOES NOT support that
conclusion.
The clip you posted even states,
"Thus, there may be usage issues that increase the percentage of tire
problems for these larger trucks, rather than exclusively a qualitative
difference between P-metric and LT tires.?"
Hopefully most folks can see that this is an apples and oranges report that
"DOES NOT" reach the conclusion that
Passenger car tires are a better choice the Light Truck Tires for a Light
Truck Application.
The other clip you posted at the bottom "Approximately 90 percent of these
light trucks use passenger car
(P-metric) tires."
Very true statement.
However these vehicles do not use a 14" or in most cases even 15" tires.
Remember our Vanagon's are not Cadillac Escalade.
The are narrow, they are heavy, they are tall ... with a very small tire
diamter.
Please show me specific passenger tires in 14"-16" sizes that meet Vanagon
requirements.
If we want to use a passenger car tires, we need to look for the following
"Minimum" specs.
* XL or RF designation.
* Load Range 100
* Max Load Capacity: 1604 lbs (after derated load capacity by 9%)
* Max Inflation Pressure:: 40 psi
- - -
Date: Tue, 4 Oct 2005 20:16:17 -0700
From: TJ Hannink <tjhannink@YAHOO.COM>
Subject: Re: Vanagon Tire Guidelines Report - Are LT Tires really safer?
DEPARTMENT OF TRANSPORTATION
National Highway Traffic Safety Administration
49 CFR Part 571
[Docket No. NHTSA-03-15400]
RIN 2127-AI54
Federal Motor Vehicle Safety Standards; Tires
AGENCY: National Highway Traffic Safety Administration (NHTSA), Department
of Transportation.
ACTION: Final rule.
Excerpt:
"FARS data for 1999 through 2001 show that 1.10 percent of all light
vehicles in fatal crashes were coded by investigators as having had tire
problems. Light trucks had slightly higher rates of tire problems (1.34
percent) than passenger cars (0.92 percent). The annual average number of
vehicles with tire problems in FARS was 528 (255 passenger cars and 273
light trucks).
A further examination of the FARS data indicates that heat is a factor
in tire problems. An examination of two surrogates for heat, the region of
the U.S. in which the crash occurred, and the season in which the crash
occurred, indicates that the highest rates of tire problems occurred in
light trucks in southern states in the summertime, followed by light trucks
in northern states in the summertime, and then by passenger cars in southern
states in the summertime. The lowest rates occurred in winter and fall.
Based on these data, tires on light trucks appear to be more affected by
higher ambient temperatures than tires on passenger cars.
Examining tire problems in the NASS-CDS from 1992 to 1999 by types of
light trucks and vehicle size indicates that LT tires used on light trucks
exhibited more problems than P-metric tires. LT tires are used on vehicle
classes identified for this analysis as Van Large B and Pickup Large B
groups of vehicles. These groups of vehicles typically consist of the
\3/4\-ton and 1-ton vans and pick-ups. P-metric tires are used on most of
the other light trucks. The data indicate that the average percentage of
light trucks in the NASS-CDS having a LT tire problem is 0.84, while the
average percent of light trucks having a P- metric tire problem is 0.47
percent. These larger pickups and vans, however, carry heavier loads and may
be more frequently overloaded than lighter trucks. In addition, these
heavier vehicles are often used at construction sites and may be more apt to
encounter nail punctures and experience flat tires. Thus, there may be usage
issues that increase the percentage of tire problems for these larger
trucks, rather than exclusively a qualitative difference between P-metric
and LT tires.?"
I know, its not definative, but does make you think especially if you live
south of the Mason-Dixon line.
Those that would like to read the whole article, it is here:
http://www.sba.gov/ADVO/laws/comments/ddot03_0926.txt
And for those of you who insist that passenger car tires can't be used on
Vanagons, I offer this:
" \7\ Americans have shifted toward a significantly higher use of
minivans, pickup trucks, and SUVs for personal travel. (Journal of
Transportation and Statistics, December 2000). Sales of light trucks have
risen steadily for over the past 20 years and now account for almost half of
the U.S. light vehicle market--more than twice their market share as
recently as 1983. (Industries in Transition, 1/01/ 00; Journal of
Transportation and Statistics, December 2000.) Sales growth of heavier light
trucks, those that have GVWRs above 6,000 pounds, increased at a much faster
rate than their lighter counterparts, with larger SUVs (6,000-10,000 pounds
GVWR) showing an average increase of 38 percent annually between 1990 and
1998.
Approximately 90 percent of these light trucks use passenger car
(P-metric) tires. The other 10 percent use light truck (LT) tires load range
C, D, or E tires, which are typically used on heavier light trucks with a
gross vehicle weight rating (GVWR) between 6,000 and 10,000 pounds.
Continued growth in the sales and production of light truck vehicles also
drove the number of original equipment light truck (LT) tires to a record
high of approximately 8.4 million units or a 25.2 percent increase over
1998's figures. (RMA 2000 Yearbook"
There is plenty more including some interesting tests of LT and Passenger
car tires in various performance and safety tests.
Good luck and good night.
TJ Hannink
