1、 WORLDWIDE ENGINEERING STANDARDS Test Procedure GMW16057 Towed Vehicle - Wheel-Lift Method Copyright 2013 General Motors Company All Rights Reserved November 2013 Page 1 of 13 1 Scope Note: Nothing in this standard supercedes applicable laws and regulations. Note: In the event of conflict between th
2、e English and domestic language, the English language shall take precedence. 1.1 Purpose. Determine vehicle towing compatibility by checking the body and chassis clearance using the wheel-lift method. 1.2 Foreword. This procedure is used for either the evaluation or development of GM Towing Informat
3、ion. 1.2.1 Test Summary. 1.2.1.1 Damage-Free Evaluations. 1.2.1.1.1 Massoit at 24 km/h (15 mph). 1.2.1.2 Function Loss Evaluation. 1.2.1.2.1 Massoit at 40 km/h (25 mph). 1.2.1.2.2 Circular Track at 113 km/h (70 mph). A related test is GMW16055, Towed Vehicle Roll Back Method. Note: Refer to Section
4、2 for additional reference documents. 1.3 Applicability. Passenger cars and light-duty trucks having a Gross Vehicle Mass Rating (GVMR) of 4536 kg (10 000 lb) or less. 2 References Note: Only the latest approved standards are applicable unless otherwise specified. 2.1 External Standards/Specificatio
5、ns. SAE J1142 SAE J1143 2.2 GM Standards/Specifications. GMW15445 GMW15474 (ID) (ID) = This standard is limited to internal distribution within General Motors and shall not be distributed outside this company. Contact the GM Lead Engineer for further instructions. 2.3 Additional References. Federal
6、Motor Carrier Regulations 393.70 and 393.71 GM Owner Manuals under Towing or Recreational Vehicle Towing - Tow Dolly GM Towing Information 3 Resources 3.1 Facilities. GM Milford Proving Ground (MPG) test roads and facilities or equivalent. Refer to 1.2.1 for the events defined at the MPG facility. 3
7、.1.1 Calibration. The test facilities and equipment shall be in good working order and shall have a valid calibration label. Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM
8、 WORLDWIDE ENGINEERING STANDARDS GMW16057 Copyright 2013 General Motors Company All Rights Reserved November 2013 Page 2 of 13 3.1.2 Alternatives. Alternative test facilities and equipment may also be used. However, all measuring variables as specified in this standard shall be determined correctly
9、with respect to their physical definition. 3.2 Equipment. 3.2.1 Tow Truck Chassis. Wheel-lift equipment should be installed on a minimum of a 4536 kg (10 000 lb) Gross Vehicle Weight Rating (GVWR) chassis. Note: Due to weight transfer considerations, industry practice suggests a minimum of 4536 kg (
10、10 000 lb) Gross Vehicle Weight Rating (GVWR) chassis be used for wheel-lift equipment. 3.2.2 Wheel-Lift. Equipment should be installed on the appropriate chassis, as recommended by the Towing Equipment Manufacturer, so the rear axle Gross Axle Weight Rating (GAWR) of the tow vehicle is not exceeded
11、 when loaded. Vehicle front axle weight should be not less than 50% of the original front axle curb weight when towing is in progress. 3.2.3 Safety Chain(s)/Cable(s). Chain(s)/cable(s) with appropriate fasteners (e.g., grab hook and/or shackle). Required in accordance with Federal Motor Carrier Regu
12、lations 393.70 and 393.71. Safety chains shall be connected to towed vehicle (see auto manufacturers recommendations) and to a structurally strong area of the towing vehicle body or boom (see towing manufacturers recommendations). 3.2.4 Steering Wheel Locking Device. Required with all wheel-lift tow
13、ing equipment with towed vehicle front or rear wheels raised. 3.2.5 Towing Information. Use towing instructions and/or towing limitations listed in GM Owner Manuals under Towing or Recreational Vehicle Towing - Tow Dolly as it is similar to the wheel-lift towing method. 3.2.6 Wheel Securing Device (
14、e.g., Wheel Straps). Required on/at each raised wheel of the towed vehicle when using wheel-lift equipment. Refer to wheel-lift manufacturer instructions. 3.2.7 Vehicle ballast. 3.2.8 Wheel alignment equipment (optional). 3.2.9 Photographic equipment. 3.2.10 Tire pressure gauge. 3.2.11 Trim height a
15、nd body panel clearance specifications. Note: All instrumentation is to be calibrated as required; record instrument details and date of calibration on Data Sheet A1, unless the information is otherwise preserved in the testing laboratory records. 3.3 Test Vehicle/Test Piece. Select a vehicle with t
16、he highest Maximum Curb Mass Rating for the vehicle year and model being evaluated. The test engineer should consider options that may reduce ground clearance when vehicle is in an in-tow attitude. These might include bumper guards, exhaust, air dams, hitches, tire diameters, or automatic level cont
17、rol. 3.4 Test Time. Technician Time: 2 to 4 hours Engineer Time: 2 to 4 hours Calendar Time to Run Test: 4 hours 3.5 Test Required Information. For additional information, reference SAE J1142, SAE J1143 or the Owners Manual. 3.6 Personnel/Skills. Technicians familiar with the proper use of wheel lif
18、t equipment and towing methods. 4 Procedure 4.1 Preparation. Note: Some heavier vehicles cannot be towed using wheel-lift methods due to towing vehicle lifting restrictions. 4.1.1 Test Engineer Preparation. 4.1.1.1 Trucks: Record cab-to-bed clearance minimum specifications, if applicable, on Data Sh
19、eet A2. 4.1.1.2 Install any optional items determined from 3.3. 4.1.1.3 Obtain specifications for J and K heights at curb mass. Record on Data Sheet A2. Measure heights. Reset to within specifications, if required. Record as tested heights on Data Sheet A2. Copyright General Motors Company Provided
20、by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW16057 Copyright 2013 General Motors Company All Rights Reserved November 2013 Page 3 of 13 4.1.1.4 Obtain specifications for front
21、and rear wheel alignment. Record on Data Sheet A2. Measure alignment and reset to within specifications, if required. Record as-tested alignment on Data Sheet A2. 4.1.1.5 Drive vehicle to determine that vehicle is operating normally and note on Data Sheet A2. 4.1.1.6 Determine maximum speed vehicle
22、can be towed on driving wheels from GM Towing Information or design direction. Record on Data Sheet A2. 4.1.1.7 The vehicle shall be tested at Maximum Curb Weight Rating plus luggage/cargo. Obtain specifications for wheel weights at Maximum Curb Weight Rating. Determine luggage/cargo weight to be us
23、ed. Note: Reference the Vehicle Ballast Test Procedure (GMW15445) for determination of the Gross Vehicle Weight (GVW) Cargo Ballast. Record on Data Sheet A3. 4.1.1.8 Record lowest manufacturers recommended tire pressure on Data Sheet A3 (reference 4.1.2.1). 4.1.1.9 Determine the gear position of tra
24、nsmission for Front-up and Rear-up towing per GM Towing Information or design direction. Record on Data Sheet A2. Reference 4.3.1.5. 4.1.1.10 Determine if sequence of tests is to be different. Reference note after 4.3.1.5. Consult with test technician about deviations. 4.1.1.11 If distance from cent
25、erline of rear wheels of tow truck to centerline of lifted wheels of test vehicle is known from previous testing, record on Data Sheet A3 (4.3.1.2). 4.1.2 Technician Preparation. 4.1.2.1 Adjust tire pressure (if required) per test engineer (reference 4.1.1.8). 4.1.2.2 Ballast the test vehicle to tes
26、t engineer direction per 4.1.1.7. Record the as-tested individual wheel weights on the Data Sheet A2, reference 4.1.1.7. Light-duty trucks: Measure and record J-K heights after ballasting. 4.1.2.3 Make a pretest inspection. Record the following on the Data Sheet A2. a. Condition of lifted chassis co
27、mponents and supporting system. b. Paint damage to body panels or other components (i.e., spoilers, air dams). c. Conduct general underbody inspection. Include deformation of components/or possible contact in area of wheel-lift cradle (i.e., oil pan, transmission pan, spoilers, rocker panels). Also,
28、 inspect lift attachment. Caution: Use jack stands when inspecting under vehicle that is raised with lift equipment. This will prevent injury in case of a wheel-lift failure. 4.1.2.4 Calibrate towing vehicle speedometer, if necessary. 4.1.2.5 Record tow vehicle and wheel-lift equipment manufacturer
29、on Figure A2. Verify safe steering towing limits per Figure A2. Also verify that the tow vehicle GVWR and GAWR are not exceeded from Figure A2. 4.1.2.6 Trucks. Set cab-to-bed clearance per 4.1.1.1. 4.2 Conditions. 4.2.1 Environmental Conditions. Not applicable. 4.2.2 Test Conditions. Deviations from
30、 the requirements of this standard shall have been agreed upon. Such requirements shall be specified on component drawings, test certificates, reports, etc. 4.3 Instructions. Warning: This test does not specify all instructions for proper towing methods and wheel-lift use. Follow accepted industry s
31、tandards for towing methods and wheel-lift equipment instructions throughout this test. 4.3.1 Front-Up Tow. 4.3.1.1 Set front wheels in straight-ahead position. Place ignition switch in off (not lock) position to release steering wheel lock. Secure steering wheel with locking device (reference 3.2.4
32、). Caution: Do not use the vehicles steering wheel locking device during towing. 4.3.1.2 Place tow vehicle and test vehicle on level ground. Attach wheel-lift device to front wheels using equipment manufacturers towing instructions. 4.3.1.2.1 Retaining rods or L-arms should be set as close to tire a
33、s possible without deflecting tire. Record on Data Sheet A5 the hole location of the rod or the distance L-arm is set. Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLD
34、WIDE ENGINEERING STANDARDS GMW16057 Copyright 2013 General Motors Company All Rights Reserved November 2013 Page 4 of 13 4.3.1.2.2 Raise vehicle until there is 254 mm (10 in) clearance between bottom of lifted tires and ground. Record left and right tire clearance on Data Sheet A5. 4.3.1.2.3 Set whe
35、el lift stinger extension. Allow enough clearance between towed vehicle and test vehicle to make turns. However the stinger should be set as close as possible (allowing for turns) to truck to reduce test vehicle bounce. This method is also taught in towing schools. Record distance from centerline of
36、 rear wheels of tow truck to centerline of lifted wheels on test vehicle. This will enable test to be repeated at the proper wheel lift stinger extension. 4.3.1.2.4 Measure and record ground clearance to closest hard and soft components (reference 7.1) at the non-lifted end of the test vehicle. If c
37、learance to any component is less than 101 mm (4 in), consult with test engineer who will decide if a towing dolly shall be used. Record use of dolly, if applicable. 4.3.1.2.5 When dollies are used, increase front tire ground clearance by same amount that vehicle height is increased by use of the to
38、wing dolly. 4.3.1.2.6 Measure and record clearance of closest hard and soft components between lifted end of vehicle and wheel lift equipment (i.e., stinger). 4.3.1.3 Connect wheel securing device, i.e., wheel straps (reference 3.2.6). Connect safety chains/cables (reference 3.2.3). Caution: Use saf
39、ety stands/blocks when connecting safety chains/cables to prevent injury, if wheel lift equipment malfunctions. 4.3.1.4 With vehicle raised, inspect for items listed in 4.1.2.3. Record on Data Sheet A5. 4.3.1.5 Shift transmission (and Four Wheel Drive (4WD) transfer case) to position per test engine
40、er direction, reference. Note: The following sequence is recommended. Events may be reordered, but final validation should include all tests. The sequence given is judged to be in increasing order of road input severity. When traveling from event to event, take the smoothest roads possible and do no
41、t exceed 48 km/h (30 mph). 4.3.1.6 Damage Free Evaluation. 4.3.1.6.1 Massoit Bump at 24 km/h (15 mph). 4.3.1.6.1.1 Tow vehicle from garage to Hyne Road entering from the east via Pickett Lake Road. Verify 254 mm (10 in) tire to ground clearance. Drive westbound, crossing the Massoit Bump at 24 km/h
42、(15 mph). 4.3.1.6.1.2 Repeat inspection per 4.1.2.3. Record observations on Data Sheet A5. 4.3.1.7 Function Loss Evaluation. 4.3.1.7.1 Massoit Bump at 40 km/h (25 mph). 4.3.1.7.1.1 Tow vehicle from garage to Hyne Road entering from the east via Pickett Lake Road. Verify 254 m (10 in) tire to ground
43、clearance. Drive westbound, crossing the Massoit Bump at 40 km/h (25 mph). 4.3.1.7.1.2 Repeat inspection per 4.1.2.3. Record observations on Data Sheet A5. 4.3.1.8 Circular Track. Drive to Circular Track via Track Access Road. Verify 254 m (10 in) tire to ground clearance. 4.3.1.8.1 Towed Vehicle on
44、 Driving Wheels. Accelerate to maximum tow speed determined in 4.1.1.6. Note resonant speed(s), if any, at which tow vehicle pitching (reference Figure 1) and/or towed vehicle side-to-side motion occurs. Also, note any wobble or shimmy of towed vehicle due to suspension. 4.3.1.8.1.1 Complete this in
45、itial lap at the maximum tow speed. Run one additional lap at each of any resonant speed(s) noted. If no resonant speed was noted, repeat at maximum tow speed. 4.3.1.8.1.2 Towed Vehicle on Non-Driving Wheels. Accelerate to 104 km/h (60 mph). Note resonant speed(s), if any, at which tow vehicle pitch
46、ing and/or towed vehicle side-to-side motion occurs. Also, note any wobble or shimmy of towed vehicle due to suspension. Complete this initial lap at 104 km/h (60 mph) except where noted above. Run one additional lap at each of any resonant speed(s) noted. If no resonant speed was noted, repeat at 1
47、13 km/h (70 mph) as described above. 4.3.1.8.2 Record on Data Sheet A5 any resonant speed(s) or wobble/shimmy noted. 4.3.1.8.3 Repeat inspection per 4.1.2.3. Record observations on Data Sheet A5. Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for Resale
48、No reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW16057 Copyright 2013 General Motors Company All Rights Reserved November 2013 Page 5 of 13 4.3.2 Rear-Up Tow. 4.3.2.1 Set front wheels in straight-ahead position. Place ignition switch in off (
49、not lock) position to release steering wheel lock. Secure steering wheel with locking device (reference 3.2.4). Caution: Do not use the vehicles steering wheel locking device during towing. 4.3.2.2 Place tow vehicle and test vehicle on level ground. Attach wheel-lift device to rear wheels using equipment manufacturers Towing Instructions. 4.3.2.2.1 Retaining rods or L-arms should be set close to tire as possible without deflecting tire. Record on D
