[Federal Register Volume 65, Number 186 (Monday, September 25, 2000)]
[Notices]
[Pages 57643-57649]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-24584]
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DEPARTMENT OF TRANSPORTATION
National Highway Traffic Safety Administration
Denial of Motor Vehicle Defect Petition, DP00-001
AGENCY: National Highway Traffic Safety Administration (NHTSA),
Department of Transportation.
ACTION: Denial of petition for a defect investigation.
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SUMMARY: This notice sets forth the reasons for the denial of a
petition submitted to NHTSA under 49 U.S.C. Sec. 30162, requesting that
the agency commence a proceeding to determine the existence of a defect
related to motor vehicle safety. The petition is hereinafter identified
as DP00-001.
FOR FURTHER INFORMATION CONTACT: Dr. George Chiang, Office of Defects
Investigation, NHTSA, 400 Seventh Street, SW, Washington, D.C. 20590.
Telephone: (202) 366-5206.
SUPPLEMENTARY INFORMATION: Mr. Dave Blum (petitioner), 5329 Eagles Nest
Road, Fruitland Park, Florida 34731, submitted a petition to NHTSA by
letter dated February 1, 2000, requesting that an investigation be
initiated on trailer towing hitch platforms (receivers) and related
hitch equipment for ``compatibility with National Highway Safety
Standards for materials and construction specifications.''
Mr. Blum is a safety committee member of the Region 3 Wally Byam
Caravan Club International Airstream travel club. He provided pictures
and descriptions of four club members' tow vehicles with cracked
Original Equipment Manufacturer hitch receivers. The tow vehicles were
model years (MY) 1993, 1994, and 1997 General Motor Corporation
Suburban Sport Utility Vehicles and a MY 1995 Dodge 2500 pickup truck.
NHTSA has reviewed and analyzed all available information. The
result of this review and analysis is set forth in a Petition Analysis
Report for DP00-001 and is published in its entirety as an appendix to
this notice.
For the reasons presented in the petition analysis report, it is
unlikely that NHTSA would issue an order concerning the notification
and remedy of a safety-related defect at the conclusion of an
investigation. Therefore, in view of the need to allocate and
prioritize NHTSA's limited resources to best accomplish the agency's
safety mission, the petition is denied.
Authority: 49 U.S.C. 30162(d); delegations of authority at CFR
1.50 and 501.8.
Kenneth N. Weinstein,
Associate Administrator for Safety Assurance.
Appendix--Petition Analysis--DP00-001
1.0 Introduction
Mr. Dave Blum (petitioner), Fruitland Park, Florida, submitted a
petition to NHTSA by letter requesting that an investigation be
initiated on trailer towing hitch receivers (platforms) and related
hitching equipment ``to assess their compatibility with National
Highway Safety Standards for materials and construction
specifications.'' The petitioner, who is a member of the Wally Byam
Caravan Club International (WBCCI) Airstream travel club safety
committee stated that NHTSA's Office of Defects Investigation (ODI)
should open an investigation concerning hitch receiver failure
because the WBCCI Airstream travel club members allegedly inspected
and found cracks in their hitch receivers.
2.0 Vehicle Information
2.1 Subject Vehicle
In his petition, Mr. Blum did not specify the make, model, or
year of vehicles he wanted ODI to investigate. However, between
December 1999 and January 2000, he supplied information concerning
cracked hitch receivers on a 1993, 1994, and 1997 model year (MY)
General Motor Corporation (GM) Suburban vehicle and on a 1995 MY
Dodge 2500 pickup (PU) truck. ODI selected MY 1992--1997 GM Suburban
vehicles as the subject vehicles for the following reasons: (1) the
petitioner identified three Suburban vehicles with cracked Original
Equipment Manufacturer (OEM) hitch receivers; (2) the ODI consumer
complaint database contained a relatively high number of complaints
on the subject vehicles; (3) the Suburban has one of the largest
towing capacities among the peer vehicles and is commonly used to
tow large travel trailers; and (4) ODI had conducted a previous
investigation (PE95-036) on certain GM Sport Utility Vehicles
(SUVs), including MY 1992-1995 Suburbans to investigate a similar
OEM hitch receiver crack problem.
2.2 Vehicles Involved
GM produces the Suburban for both the Chevrolet and GMC
Divisions. The combined number of subject vehicles produced in the
United States was 738K vehicles.\1\ The Chevrolet Division accounted
for 512K
[[Page 57644]]
vehicles and the GMC Division accounted for 226K vehicles. According
to GM, among the 738K vehicles, 494K vehicles were equipped with
factory installed OEM hitch receivers.
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\1\ Ward's Automotive Yearbook, 1992--1998 Editions for MY
1992--1997 Suburbans.
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3.0 Previous Recalls and Investigations of Hitch Receivers
ODI is aware of one recall and one previous investigation
concerning hitch receiver cracking. DaimlerChrysler recalled certain
MY 1998-2000 Dodge 2500 Ram pickup trucks (Recall 00V-107) because
the steel had insufficient strength due to poor quality control. ODI
opened a Preliminary Evaluation, PE95-036, in June of 1995 into an
alleged defect in MY 1992-1993 Suburban vehicles after receiving
four (4) complaints, one MY 1992 and three (3) MY 1993, concerning
cracked hitch receivers. During this investigation, ODI expanded the
scope to include other MY 1992-1995 GM SUVs. By the conclusion of
the investigation in late 1995, ODI had received another complaint
(MY 1992) and GM reported three (3) additional complaints (one MY
1992 and two MY 1993) bringing the complaints to a combined total of
eight (8). The investigation revealed no injuries or crashes related
to the alleged defect on the subject vehicles. ODI closed the
investigation without any further actions and concluded the
following:
* * * it appears that the cracks are readily obvious and slow to
propagate. The problem may not be a catastrophic failure of the
hitch platform. The high number of warranty claims coupled with the
corresponding low number of failures is not indicative of a safety
trend at this time.\2\
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\2\ NHTSA ODI PE95-036 (J. Abbott) of 31 October, 1995 (closing
resume).
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4.0 Hitch Receiver/Equipment and Towing Limits
Currently, there are no Federal Motor Vehicle Safety Standards
(FMVSS) applicable to trailer towing hitch equipment. However, many
hitch equipment manufacturers use the Society of Automotive
Engineers Standard, SAE J684,\3\ for hitch classification and test
limits. According to SAE J684 (Table 1), there are four classes of
towing capacities or tow ratings for applications less than 10,000
lb. When used with a weight distributing hitch system, the Suburban
has a 10,000 lb. maximum towing capacity with the driver and one
passenger onboard and no cargo in the tow vehicle. The additional
weight of other occupants and cargo in the tow vehicle will reduce
the towing capacity accordingly.
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\3\ ``Trailering Couplings, Hitches, and Safety Chains--
Automotive Type''--SAE J684 (6/98).
Table 1.--Various Types of Hitch Receivers
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Max. towing
Class rating per SAE J684 Towing duty weight (in Hitch system attachment Common payloads
pounds) type
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Class I........................... Light................ 2,000 Weight Carrying (WC)...... Monocycle & Jet Ski trailers.
Class II.......................... Medium............... 3,500 WC........................ Small Boat & utility trailers.
Class III......................... Heavy................ 5,000 WC........................ Med. travel & utility trailers, Large boat
trailers.
Class IV.......................... Heavy................ 10,000 Weight Distributing....... Large travel & utility trailers Automotive
trailers.
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4.1 Hitch Receiver
Figure 1 shows a diagram of a typical frame mounted Class III/IV
type hitch receiver. There are three basic sections that make up a
hitch receiver: (1) the hitch bar and ball assembly that connects
the trailer to the tow vehicle, (2) the horizontal box transfer beam
and (3) the vertical mounting flanges for attachment to the vehicle
frame. Note that the diagram also shows the typical crack patterns
found as reported by the petitioner.
[GRAPHIC] [TIFF OMITTED] TN25SE00.057
[[Page 57645]]
4.2 Weight Distribution (WD) Hitch System
Normally, on the lighter duty Class I/II/III applications, the
trailer's tongue weight directly pushes down on the hitch receiver's
coupling ball causing the rear of the tow vehicle to drop and the
front of the vehicle to rise slightly. With larger and heavier
trailers, this can severely affect vehicle handling and stopping
distances and further add stresses to the tow vehicle and hitch
receiver structures. To reduce these undesirable effects, an
`aftermarket' or `third party' Weight Distribution (WD) hitch system
must be used when towing large trailers. For Class IV applications
with the WD system as shown in the set up of Figure 2, the two
spring bars are bent upward to apply a counter moment torque to the
WD hitch ball mount assembly and redirect or redistribute the point
load tongue weight further forward in the tow vehicle. The subject
vehicles' hitch receiver has a decal specifying 10,000 lb. towing
and 1,000 lb. maximum tongue weight limits when used with the WD
hitch system.
4.3 Proper Installation of the WD Hitch System
Based on the information obtained from various trailering
sources,\4\ a properly installed WD hitch system evenly distributes
the loads to the entire tow vehicle. The WD hitch system's spring
bars force both the front and rear wheel fenders equally downward.
This aligns the tow vehicle so that it is approximately the same
`attitude' or `level' as it was before the trailer was hooked up. A
poorly installed WD hitch system can cause the tow vehicle's front
end to `lift up' resulting in more weight to the hitch receiver and
rear axle. In addition, the ball mount height, spring bar angles,
spring bar engagement level, and ball mount receiver bar length can
also affect the proper installation and effectiveness of the WD
hitch system.
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\4\ Various Trailering Guides: Ford 2000 RV & Trailer Towing
Guide (8/99); Reese `Hitching-Up Procedure' distributed during
Airstream RV rally in Sarasota, Florida (2/00); 1997 Airstream 34'
Excella Travel Trailer Owners Guide, Sections B and I on Hitching Up
and Trailer Specifications; GM Suburban Owners Manuals, Section 4--
`Towing a Trailer', MY 1993-1997; GM Suburban Sales Brochures,
Section on Trailering, MY 1993-1997; and GMC Trailering Guides, MY
1993-1997.
[GRAPHIC] [TIFF OMITTED] TN25SE00.056
4.4 Hitch Receiver Performance
For Class IV hitch receivers, SAE recommends a series of static
test loads applied to the hitch ball mount and receiver to verify
their towing limits. The static test loads include longitudinal,
transverse, vertical and moment loads. According to SAE,\5\ these
static test loads are higher than the loads encountered during
actual on-road towing. For example, the 2,100 lb. SAE specified
vertical load is more than twice that of the typical trailer tongue
weight limit of 1,000 lb. Tests conducted by SAE in the mid-1990s
verified that the actual measured dynamic loads under normal towing
conditions, such as turns, hills, dips and stops, are well within
the higher SAE specified static loads. However, SAE also cautioned
that abuse or mishaps such as backing into an object or one side of
the trailer falling off the pavement can create loads that exceed
the SAE specified loads. Remote and unimproved roadways and certain
stretches of highways, with short concrete slabs causing the trailer
to ``porpoise'' or oscillate up and down severely, can also create
higher than normal loads at the hitch receiver.
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\5\ Discussions with SAE J684 Group Chairman, Mr. Jim Fait,
during April and May of 2000.
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5.0 Complaints
5.1 Complaints Submitted to ODI on the Subject Vehicles
ODI searched and analyzed all complaints involving the subject
vehicles in its consumer database pertaining to an alleged cracked
hitch receiver. As of August 1, 2000, the ODI database had recorded
15 cracked hitch receiver complaints on the subject vehicles. As
shown in Table 2, the complaint dates, by calender year, were as
follow: five in 1995, one in 1996, two in 1998, one in 1999 and six
in 2000. There are high concentrations of complaints submitted in
years 1995 and 2000. The first complaint concentration in 1995 was
due to an effort of a Northeast region WBCCI Airstream travel club
who surveyed its members and submitted all five of the complaints to
ODI. The second complaint concentration in year 2000 was due to the
efforts of the petitioner's Southeast region Airstream travel club
safety committee in conjunction with ODI personnel during the
February 2000 RV Rally in Sarasota, Florida. The inspections and
field survey during the rally resulted in the submission of five of
the six CY 2000 complaints in the ODI database. Otherwise, ODI has
received only one or two complaints per year on the subject
vehicles.
[[Page 57646]]
Table 2.--ODI Complaints by Calendar Year
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Calendar year CY95 CY96 CY97 CY98 CY99 CY00 Total
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Suburban Total................. 5 1 0 2 1 6 15
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Table 3 shows the complaint counts by model year for the subject
vehicles equipped with the OEM installed hitch receivers. Among the
fifteen Suburban complaints, eleven complainants were contacted
during this petition analysis and they all reported towing 29' and
longer Airstream trailers having a listed Gross Vehicle Weight
Rating (GVWR) ranging from 7,000 to 9,800 lb. Most of the
complainants never weighed their trailer and do not know the actual
gross trailer towing weight (trailer plus cargo in both the tow
vehicle and trailer). One recent (CY 2000) complainant reported that
prior to towing his current 31' trailer, he was towing a 30' long
trailer when the trailer's wheels hit a large pothole on the road.
The impact was severe enough to damage the trailer's frame and
totally destroyed the trailer structure. After receiving the
Airstream RV club's newsletter which asked members to inspect their
hitch receivers, he found cracks in the hitch receiver. It is
unclear whether the cracks were caused by the impact with the
pothole or inappropriate loading, or initiated from incorrect
installation and usage of the WD hitch system. ODI was unable to
contact the other four complainants despite attempting to reach them
at the addresses and telephone numbers they provided.
Table 3.--ODI Complaints and Complaint Rates on the Subject Vehicles and Peer Vehicles
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Pop. with
Model year MY92 MY93 MY94 MY95 MY96 MY97 Total hitch Rate
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Suburban Total........................................... 2 6 4 0 2 1 15 494K 3.0
Dodge PUs................................................ 1 0 0 3 0 0 4 495K 0.8
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5.2 Complaints Submitted to ODI on Peer Vehicles
ODI has also searched for cracked hitch receiver complaints in
its database on other MY 1992-1997 trucks and vans having similar
towing capacities. Except for the Dodge D-150/250/350 and B-1500/
2500/3500 series pickup trucks (see Table 3), ODI has received no
more than one hitch receiver complaint on any other vehicle. The
complaint rate for cracked hitch receivers on the Dodge truck with
OEM hitch receivers is 0.8 per 100,000 vehicles \6\ as compared with
the subject vehicles' rate of 3.0 per 100,000 vehicles.
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\6\ Dodge light duty pickup truck population equipped with OEM
hitch receivers suppled by DCX on 6/20/00.
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6.0 Inspection and Survey at the Recreational Vehicle (RV) Rally
6.1 Airstream RV Rally in Sarasota, Florida
ODI personnel, at the invitation of the petitioner and the
Airstream Region 3 RV Safety Committee, attended a RV rally held in
Sarasota, Florida during the period of February 15-21, 2000. Of the
600 RV participants towing a travel trailer at the RV rally,
approximately 150 use the subject vehicle to tow a large 31'-34'
length Airstream travel trailer. Therefore, the percentage of large
travel trailers among the 600 travel trailers at the Airstream RV
rally was approximately 25%.
6.2 Physical Inspection of the Tow Vehicle Hitch Receivers
During the course of the RV rally, ODI and Airstream RV Safety
Committee personnel made several announcements requesting each RV
rally participant to inspect his/her hitch receiver for cracks. For
those that responded, ODI and safety committee personnel visited
them to further inspect their tow vehicles and trailers and to
interview the owners. The Suburban was used as the tow vehicle in 21
of the 27 units inspected. Among these 21 units, 10 had cracked OEM
hitch receivers, four had previously experienced cracked OEM hitch
receivers and since had them replaced, and the remaining seven did
not have any problems while using either the OEM or the non-OEM
hitch receiver. The older MY 1993-1994 Suburbans accounted for six
of the ten cracked receivers. Eight of the these 10 Suburban
vehicles towed or previously towed the large 31'-34' length
Airstream travel trailer with GVWR near the 10,000 lb. limit.
Among the remaining six owners who didn't have the Suburban as
their tow vehicle, there were two reports of cracked hitch
receivers. Specifically, a MY 1995 and a MY 1996 Dodge pickup truck
towing Airstream 30' and 34' travel trailers respectively.
6.3 Overloading in the RV Community
Present at this rally was the A'Weigh We Go (AWWG) weighing
service. AWWG travels across North America to large rallies to
provide an on-site weighing service and to give seminars on safe
towing practices. RV manufacturers and tire companies partially
sponsor AWWG to provide the weighing service at a nominal cost to
the participants. AWWG \7\ has weighed more than 10,000 vehicles and
trailers in the past 10 years including motorhomes, tow vehicles,
5th wheel trailers, and travel trailers (TTs). The majority of the
data collected were from motorhomes (5,462 units) and the least
amount of data collected were from travel trailers (462 units). They
found that overloading or improper matching of equipment and loading
is a common problem in the RV communities. Among the 462 travel
trailers they have weighed over this period, 54 percent of the tow
vehicles and 51 percent of the TTs exceeded load limits in one or
more of the loading limits such as the Gross Combination Weight
Rating (GCWR), the Gross Vehicle Weight Rating (GVWR), Gross Axle
Weight Rating (GAWR), Tire Load Rating (TLR) or net vertical hitch
loading. AWWG noted the following concern in their handbook:
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\7\ A'Weigh We Go Recreation Vehicle Weight & Tire Safety
Handbook, Textbook Edition, Section I, Rev. 1/00.
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Of particular concern is that 57% (percent) were over GCWR,
indicating that too many folks are trying to pull too much trailer
with too little truck.
6.4 Weighing of Units at the Florida RV Rally
ODI contracted with AWWG to use their weighing services during
the Florida RV rally. ODI then requested all of the Suburban owners
with cracked hitch receivers and randomly selected a few of the
owners without cracked hitch receivers to have their units weighed
by the AWWG (at ODI's expense) at the conclusion of the RV rally.
ODI instructed each owner to prepare the tow vehicle and trailer as
they normally would for road travel. Prior to the day of departure,
AWWG weighed each tow vehicle without the trailer attached. Then, on
departure day, AWWG weighed the entire tow vehicle and trailer
assembly at each wheel and axle. By measuring the loads at each
wheel, AWWG can determine if the loads exceed any of the GCWR, GVWR,
GAWR limits for both the tow vehicle and the trailer. AWWG also
measured and calculated the total trailer towing weight and the net
vertical loading on the tow vehicle. According to AWWG, the net
vertical loading on the tow vehicle rear axis is roughly equal to
the trailer tongue weight within an error of 50 lb.\8\ By comparing
the measured vehicle loads with the manufacturer's load limits, AWWG
can
[[Page 57647]]
calculate the amount of `weight margins' or `weight overloading' in
each of these areas.
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\8\ Discussons with AWWG president, Mr. J. Anderson, during
March-April 2000. Data taken from AWWG's weighing of both tongue and
vertical weighing of both tongue and vertical weights on travel
trailers in early 1990's.
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During the RV rally, AWWG used calibrated commercial/industrial
grade weighing scales that measure up to 20,000 lb. each with an
accuracy to +/-50 lb.\9\ Many law enforcement agencies use the same
type of scale during their highway truck inspections. Throughout the
weighing process, ODI personnel observed that AWWG was careful to
keep the vehicle and/or trailer level during weighing in order to
obtain the most accurate and consistent readings.
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\9\ AWWG Weighing Devices--Model WL 101, Range 0-20,000 lb.,
Class III Accuracy, Load-O-Meter Corporation, Baltimore, MD.
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6.5 AWWG Data Review
AWWG weighed nine of the 10 Suburban vehicles with cracked OEM
hitch receivers. One owner did not make his vehicle and trailer
available for weighing. Eight of the nine weighed units showed
overloading in at least one category. Note that these recorded load
conditions represent only the load conditions while attending the
week-long RV rally. Table 4 shows the various load conditions for
each of the nine weighed units. The percentage of the rated load
limit, shown as a ``+'' value, represents the margin within which
the vehicle/trailer is below the maximum weight rating, and the
percentage over the rated load limit, shown as a ``-'' value,
represents overloading. Many owners exceeded weight limits in more
than one rating. One owner (ID #1) exceeded six of the nine weight
limits. Based on the weight data, overloading appeared to be a major
contributing factor in cracked hitch receivers. The two vehicles
listed at the bottom of the table (ID #8 & #9) that recorded the
least amount of overloading and no overloading, respectively, had
previously towed a larger and heavier 34' travel trailer, and that
may have been the cause of the cracked hitch receivers.
The remaining seven Suburban vehicles with cracked hitch
receivers that were weighed had from one to six failed rating areas
out of the possible nine areas. Additionally, six of these seven
units exceeded either the 10,000 lb. trailer towing or 1,000 lb.
tongue weight limits as specified on the OEM hitch receiver.
6.6 Weights of Large Travel Trailers
Many modern RV trailers have comforts and amenities that help
make mobile traveling more like a home on wheels. Full size bedroom,
kitchen, bath, recliner and sofa are standard on many 28' or larger
trailers. Many RV manufacturers can equip these trailers with
additional options such as ceramic tile floors, stone counter tops,
microwave oven, entertainment center, satellite/computer systems and
room slide-outs. All these items add additional weight to the basic
trailer. The more the trailer weight is above the empty Dry Weight
condition, the less `cargo' capacity is available to the consumer
before reaching the trailer GVWR and the hitch receiver's towing
limit. For example, Airstream rates their MY 2000 34' length Limited
travel trailers at 8,290 lb. Dry Weight and a GVWR of 9,800 lb.
maximum\10\ resulting in a Net Carrying Capacity (NCC) of only 1,510
lb. This NCC would include any additional dealer or owner-installed
options, fluids, LP gas, personal items such as food, clothing,
television, furniture, kitchen wares, books, and repair tools. In
addition, relocating some loads from the trailer to the tow vehicle
may help keep from exceeding the trailer's GVWR, but still
diminishes the towing capacity of the hitch receiver from the 10,000
lb. maximum rating. Note that in a ``remote'' camping environment
where there are no utilities, the camper may have the 54-gallon
fresh water tank and the twin 20-gallon LP tanks filled to full
capacities. These two items alone account for a combined weight of
more than 600 lb. of the available NCC. In the Airstream web
site,\11\ the following disclaimer appears at the bottom of every
page:
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\10\ Thor Industries, Inc. Airstream, An American Legend 2000
Sales Brochure.
\11\ Thor Industries, Inc. Airstream Travel Internet web site at
http://www.airstream-rv.com 5/00.
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Vehicle Loading: Every effort has been made to provide the
greatest number of options for the recreation vehicle owner. Along
with these choices comes the responsibility to manage the loads that
are imposed by the choices so that they remain within the
manufacturer's specified chassis weight limits. Do not overload the
recreation vehicle.
Dry weights based on standard features; optional equipment not
included. Net carrying capacity (NCC) determined by subtracting
unloaded vehicle weight (UVW) from gross vehicle weight (GVWR) and
includes fluids, options and cargo. Liquid capacities and weights
are approximations only.
Besides a safety seminar given by the RV club's safety committee
at the Florida rally, AWWG also presented a safety seminar there.
During the seminar, AWWG reported that ``the average couple carries
about 2,000 lb. of stuff and the average full-timer, about 3,000
lb.'' which was documented in its handbook.\12\ Many of the
participants at the RV rally were retired ``full-timers,'' including
all of the Suburban owners with cracked hitch receivers.
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\12\ A Weigh We Go Recreation Vehicle Weight & Tire Safety
Handbook, Textbook Edition, Section VI, Rev. 1/00.
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Although not included in Table 4, because the owners did not
report any hitch receiver problems, seven other Suburban vehicles
towing large trailers with OEM and non-OEM hitch receivers,
including the one belonging to the petitioner, were also weighed by
AWWG. The results showed that overloading is also common among these
owners, but to a lesser extent.
While the WBCCI RV safety committee provides guidance to RV
owners in the proper usage of towing a trailer and the need to
regularly inspect the towing equipment, there are no Federal or
state laws that require weighing of RV trailers while traveling the
nation's interstates as there are for commercial trucks.
7.0 GM Data Review
At the request of ODI, GM supplied the following information\13\
concerning the alleged defect. GM stated that the same hitch
receiver design has been used during the entire production period of
the subject vehicles (MY 1992-1997).
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\13\ General Motor response to ODI Information Request (IR), GM
583 of 3/00 and FAX of 5/00.
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7.1 GM Owner Reports
Among the 494K MY 1992-1997 Suburban vehicles sold with OEM
hitch receivers, GM has received 15 owner complaints, one accident
claim, and has been named in two lawsuits related to the alleged
defect in the subject vehicles. Excluding non-crack-related
problems, duplicates of RV rally field survey reports and ODI
complaints, Table 5 lists the nine cracked hitch receiver complaints
from GM. The first reported litigation case involved a MY 1993
Suburban towing a 34 Airstream RV travel trailer. Prior to the case
going to trial, the owner filed a `notice of nonsuit' and the court
dismissed the case in 1/99. ODI reviewed this same report in 1995
during its investigation (PE95-036). The other litigation report
involved a MY 1995 Suburban that lost its trailer while hauling a
load of pumpkins. The owner replaced the hitch receiver before a GM
representative was able to verify the failure or determine the
cause. The report claimed approximately $1800 in damages. The one
accident claim was from the same owner as the first litigation
report. GM also reported 154 warranty claims on the subject
vehicles' hitch receiver. Based on the GM failure codes, ODI
estimates that approximately 15 to 20 percent of the claims may
involve cracks in the vertical mounting flange, but further detail
is not available. None of the complaints or warranty reports
indicate bodily injuries or vehicle crashes as a result of the
cracked hitch receivers.
Table 4.--Weight Data/Analysis on the Nine Suburban Hitch Receiver Crack Failures
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Tow vehicle overload? (percent) Trailer overload? (percent) Hitch receiver overload? (percent)
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ID Tow vehicle Trailer Trailer
Tow veh. Tow veh. Tow veh. Tire load Trailer Trailer Tire load two Wt. Vert. Wt. Remarks
GCWR GVWR GAWR limit GVWR GAWR limit 10,000 lb. 1,000 lb.
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1............................ 1994 Sub......... 34' A/S......... -4 99 92 -1 -16 -12 68 -23 -12 6 failed areas
2............................ 1996 Sub......... 34' A/S......... 99 -3 -12 94 -5 98 82 -15 -18 5 failed areas
3............................ 1999 Sub......... 34' A/S......... -1 92 77 78 -3 -13 84 -17 1 4 failed areas
[[Page 57648]]
4............................ 1993 Sub......... 31' A/S......... 80 96 93 90 -7 0 88 82 -8 3 failed areas
5............................ 1993 Sub......... 34' A/S......... 92 -5 -10 90 99 98 63 -3 84 3 failed areas
6............................ 1993 Sub......... 34' A/S......... 91 86 -4 90 91 97 79 -1 88 2 failed areas
7............................ 1995 Sub......... 30' A/S......... 85 96 -1 85 95 93 99 91 65 1 failed area
8............................ 1994 Sub......... 31' A/S......... 86 80 80 67 -1 100 95 92 63 1 failed area
9............................ 1996 Sub......... 30' A/S......... 86 87 79 97 96 91 84 91 100 0 failed area
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Notes:
GCWR--The Gross Combination Weight Rating (GCWR) is the maximum allowable combined weights from the tow vehicle and the trailer as specified by the vehicle manufacturer.
GVWR--The Gross Vehicle Weight Rating (GVWR) is the maximum allowable gross vehicle weight of the tow vehicle or trailer as specified by the manufacturer.
GAWR--The Gross Axle Weight Rating (GAWR) is the maximum allowable weight on each axle as specified by the manufacturer.
Tire Load Limit--The tire load limit is the maximum allowable load on each tire as specified by the manufacturer.
Trailer Tow Wt.--The trailer towing weight is the maximum allowable towing weight by the hitch receiver. It includes the trailer weight, as well as any additional occupant and cargo weights in
the tow vehicle.
Vert. Wt.--The hitch vertical weight is the maximum net vertical loads on the rear axis after trailer hookup. According to AWWG, the vertical weight is approximately the same as the hitch
tongue weight.
Table 5.--GM Complaints and Reports on Hitch Receiver Cracking
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ID DOI Tow vehicle Trailer mileage Trailer weight Nature of failure Est. damage cost GM/dealer action
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99-6701........... 6/99 '96 Sub........... 6K vehicle miles.. 32' Jayco Est. 1'' crack both Not Available (n/a). 100% Goodwill (G/W).
9K. sides.
99-7801........... 8/99 '94 Sub........... 100K vehicle miles Car Trailer Est. Side plate broke $0.9K on trailer.... Denied.
6,5K. off.
99-6101........... 9/99 '94 Sub........... Est. 120K tow 27 Jayco RV Est. Broken & cracked. N/A................. Denied.
miles. 8K.
99-7001........... 11/99 '95 Sub........... 45K vehicle miles. A/S trailer N/A.. Broken & cracked. N/A................. Under warranty.
99-0994........... 8/99 '96 Sub........... 43K vehicle miles. RV trailer N/A... Broken-trailer N/A................. 75% G/W.
separation.
99-4148........... 12/99 '94 Sub........... 57K vehicle miles. A/S trailer N/A.. Cracked on both N/A................. Denied.
sides.
99-1001........... 3/00 '93 Sub........... Est. 60K tow miles A/S 32' trailer Broken & cracked N/A................. Denied.
6.5K+. on both sides.
99-6101........... 10/94 '93 Sub........... 160K vehicle miles A/S trailer N/A.. Broken & crack... N/A................. Denied.
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7.2 GM Hitch Receiver Design, Test and Performance Limits
During the development phase, GM conducted both nondestructive
analysis and destructive testing on their hitch receiver design.
This included Finite Element Analysis (FEA), static load testing and
on-road durability tests. GM's FEA, as well as the static load
testing, support GM's opinion that the hitch receiver will perform
as designed. Both GM and other hitch receiver manufacturers use the
same static load limits found in the SAE standard. In addition, GM
successfully conducted a 6,500 mile on-road durability test with a
Suburban towing a 10,000 lb. trailer having 1,000 lb. tongue weight
over various road conditions without cracks or hitch receiver
failure. According to GM, due to the course's hilly terrain, this
test is equivalent to 20,000 normal towing miles. It should be noted
that GM does not identify the ``towing rating with no cargo''
limitation anywhere on the hitch receiver, on the vehicle, or in any
of the pre-1996 owners' manuals. However, this limitation is
specified in their trailering guides.
7.3 GM's Assessment of the Crack Hitch Receiver Problems
GM concluded that based on its data:
All test and analysis documents within GM's possession indicate
that the subject component will perform without failure in the field
if load limitations are met. GM believes that loaded trailer weights
in the field may exceed 10,000 lb. and that loaded trailer tongue
weights in the field may exceed 1000 lb. It is GM's belief that if
the hitch platform is used within the confines as described by GM in
various, readily available trailering usage documents, the subject
component will perform without failure.
8.0 Conclusions
1. There are no Federal Motor Vehicle Safety Standards (FMVSS)
or ``National Highway Safety Standards for materials and
construction specifications,'' as indicated in the petition,
relating to trailer hitch design. The SAE J684 trailering standard
covers classification and testing of towing equipment. For Class IV
hitch receivers, according to SAE J684, the static test loads take
into account the dynamic loads experienced during normal towing
operations.
2. An analysis of hitch receiver crack/failure complaints in the
ODI consumer complaint database and those submitted by GM reveals a
low number and rate of complaints and a lack of a complaint trend
for the subject vehicles, as well as their peer vehicles.
3. A recent field survey and weighing of the tow vehicles and
trailers conducted by ODI indicate that a combination of
overloading, improper hitch setup, and adverse road conditions
appears to be a major factor in hitch receiver failures. Eight of
nine surveyed Suburban owners at the Florida RV rally had overloaded
their vehicle/trailer in one or more areas that can affect the
structural integrity of the hitch receiver platform.
4. GM information indicates that the hitch receiver design
passes the same static loading levels as specified in SAE J684 and
also passes their on-road durability test while towing of a 10,000
lb. trailer with 1,000 lb. tongue load. GM believes that overloading
is the cause of the reported failures in the field.
5. ODI initiated an investigation on the same hitch receiver
cracking problem in 1995, but closed it in October the same year
because the total complaint rates were low and ODI could not
identify a defect trend. Since then, ODI has found no new
significant information on MY 1992-1997 Suburban vehicles to support
reopening this investigation.
6. RV owners should be educated as to the seriousness of
overloading their RVs and tow vehicles. This could be accomplished
by initiating an extensive campaign by vehicle, RV manufacturers, RV
club safety committees, and national RV associations to further
define loading limits and industry-wide terminologies, to advise
owners to avoid conditions leading to overloading of both the towing
vehicle and trailer, to inspect their towing equipment periodically,
and to install weight distributing hitch systems correctly.
7. Based on the information presented above, it is unlikely that
NHTSA would issue an order for the notification and remedy of a
safety-related defect in the subject vehicles at the conclusion of
the investigation
[[Page 57649]]
requested in the petition. Therefore, in view of the need to
allocate and prioritize NHTSA's limited resources to best accomplish
the agency's safety mission, the petition is denied.
[FR Doc. 00-24584 Filed 9-22-00; 8:45 am]
BILLING CODE 4910-59-P