1、 WORLDWIDE ENGINEERING STANDARDS Test Procedure GMW16055 Towed Vehicle - Roll Back Method Copyright 2013 General Motors Company All Rights Reserved November 2013 Page 1 of 9 1 Scope Note: Nothing in this standard supercedes applicable laws and regulations. Note: In the event of conflict between the
2、English and domestic language, the English language shall take precedence. 1.1 Purpose. Determine body and chassis performance and vehicle clearance of a towed vehicle using the rollback (flatbed or slide-back) towing method. 1.2 Foreword. This procedure is used for either the evaluation or developm
3、ent of GM Towing Information. 1.2.1 Test Summary. 1.2.1.1 Damage-Free Evaluations. Massoit at 24 km/h (15 mph). Related test is GMW16057, Towed Vehicle Wheel Lift Method. 1.3 Applicability. Passenger cars and light-duty trucks having a Gross Vehicle Mass Rating (GVMR) of 4536 kg (10 000 lb) or less.
4、 2 References Note: Only the latest approved standards are applicable unless otherwise specified. 2.1 External Standards/Specifications. SAE J1142 2.2 GM Standards/Specifications. GMW15445 GMW15474 (ID) (ID) = This standard is limited to internal distribution within General Motors and shall not be d
5、istributed outside this company. Contact the GM Lead Engineer for further instructions. 2.3 Additional References. Vehicles Owners Manual (Towing Instruction) 3 Resources 3.1 Facilities. GM Milford Proving Ground (MPG) test roads and facilities or equivalent. Refer to the events defined at the MPG f
6、acility. 3.1.1 Calibration. The test facilities and equipment shall be in good working order and shall have a valid calibration label. 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 pr
7、eserved in the testing laboratory records. 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 with respect to their physical definition. 3.2 Equipment. 3.2.1 Tow Truck Chassis. R
8、oll Back equipment should be installed on a minimum of a 4536 kg (10 000 lb) GVMR chassis. 3.2.2 Roll Back. 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 exceed
9、ed when loaded. Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW16055 Copyright 2013 General Motors Company All Rights Reserved November
10、2013 Page 2 of 9 3.2.3 Safety Chain(s)/Cable(s). 3.2.4 Vehicle Ballast. 3.2.5 Photographic Equipment. 3.2.6 Tire Pressure Gauge. 3.3 Test Vehicle/Test Piece. Select a vehicle with the highest Maximum Curb Mass Rating for the vehicle year and model being evaluated. The test engineer should consider o
11、ptions that may reduce clearance between the bed and the vehicle. These might include bumper guards, exhaust, air dam, hitches, tire diameters or automatic level control. 3.4 Test Time. Calendar time: 4 hours Test hours: 2 to 4 hours Coordination hours: 2 to 4 hours 3.5 Test Required Information. 3.
12、5.1 Towing Instructions. Use Owners Manual, Towing Instruction, or engineering direction. 3.5.2 Vehicle Trim Height. Trim height and body panel clearance specifications at Maximum Curb Mass Rating (MCMR). 3.6 Personnel/Skills. Technicians familiar with the proper use of roll back equipment and towin
13、g methods. 4 Procedure 4.1 Preparation. 4.1.1 Test Engineer Preparation. 4.1.1.1 Tow Truck. Record tow vehicle and roll back equipment manufacturer and record on Data Sheet A2. Also verify that the tow vehicle GVWR and GAWR are not exceeded. Record manufacturers information including specifications.
14、 4.1.1.2 Roll Back Ramp Angle. Determine ramp angle. 4.1.1.2.1 Record equipment manufacturer ramp angle and record on Data Sheet A2. If necessary, calculate ramp angle by recording measurements per Figure A1 in table on Data Sheet A2. 4.1.1.2.2 Refer to Figure A1 Roll Back Ramp Angle and Figure A2 A
15、dd Lumber. If necessary, add lumber per Figure A2 to set ramp angle equal 13 degrees. Record added lumber details on Data Sheet A2. 4.1.1.3 Drive vehicle to determine that vehicle is operating normally and note on Data Sheet A3. 4.1.1.4 Install any optional items determined from 3.3. 4.1.1.5 Obtain
16、specifications for Front and Rear rocker to ground dimension (J-K) heights at curb mass. Record on Data Sheet A3. Measure heights. Reset to minimum specifications. 4.1.1.6 Curb Mass. The vehicle shall be tested at the Maximum Curb Mass Rating plus luggage/cargo. Obtain specifications for wheel weigh
17、ts at Maximum Curb Mass Rating. Determine luggage/cargo mass to be used. Note: Reference the Vehicle Ballast Test Procedure (GMW15445) for determination of the GVW Cargo Ballast. Record on Data Sheet A3. 4.1.1.7 Record the lowest manufacturers recommended tire pressure on Data Sheet A3. 4.1.1.8 If t
18、he vehicle is equipped with shock absorbers that have limited damping in the key off mode, reference the GM Towing Instructions. 4.1.1.9 Determine if sequence of tests is to be different. Consult with test technician about deviations. 4.1.2 Technician Preparation. 4.1.2.1 Adjust tire pressure (if re
19、quired) per test engineer. Reference 4.1.1.7. 4.1.2.2 Ballast the test vehicle to test engineer direction per 4.1.1.6. Record the as-tested individual wheel weights on the Data Sheet A3. Reference 4.1.1.6. 4.1.2.3 Make a pretest inspection. Record the following on the Data Sheet A4. 4.1.2.3.1 Condit
20、ion of chassis components and supporting system. Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW16055 Copyright 2013 General Motors Comp
21、any All Rights Reserved November 2013 Page 3 of 9 4.1.2.3.2 Paint damage to body panels or other components (i.e., spoilers, air dams). 4.1.2.3.3 Conduct general underbody inspection. Include deformation of components or possible contact of ramp and winch (i.e., oil pan, transmission pan, spoilers,
22、or rocker panels). 4.1.2.3.4 Check the attachment (shipping) slots for deformation, cracking, etc. Also, inspect truck bed and winch. 4.1.2.4 Load the vehicle using the roll back winch. Record any contact with the ramp or body with the vehicle. The winch is not to be used as a tie down. 4.1.2.5 Atta
23、ch tow truck winch to vehicle following industry standards for roll back towing method. If attachment point is not available, consult with test engineer who will decide correct attachment points. Record on Data Sheet A4, Figure A3. 4.1.2.6 Install the tie down chains in such a manner that the chains
24、 do not contact the vehicle, except for the appropriate tie down area on the vehicle. 4.1.2.7 Inspect vehicle for damage after loading and securing to roll back surface. 4.2 Conditions. 4.2.1 Environmental Conditions. Not applicable. 4.2.2 Test Conditions. Deviations from the requirements of this st
25、andard 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 roll back use. Follow accepted industry standards for towing method an
26、d roll back tow equipment instructions throughout this test. 4.3.1 Front-Winch Loading. 4.3.1.1 Damage-Free Evaluation. Check front clearances from the vehicle to the roll-back bed when the front tires reach the edge of the bed or lumber, if used. Check loading clearances at the rear of the vehicle
27、when the rear tires reach the edge of the bed or lumber if used. Verify clearances to the closest soft and hard components. Record on Data Sheet A4. 4.3.1.2 Massoit Bump at 24 km/h (15 mph). 4.3.1.2.1 See GM Testing Standards for specifics on Massoit Bumps. (Contact GM Responsible Engineer for direc
28、tion on which Testing Standard to review). 4.3.1.2.2 Repeat inspection per 4.1.2.7. Record any observations on Data Sheet A4. 4.3.1.3 Return to the garage area. 4.4 Rear-Winch Loading. 4.4.1 Damage Free Evaluation. Check rear clearances from the vehicle to the roll-back bed when the rear tires reach
29、 the edge of the bed or lumber, if used. Check loading clearances at the front of the vehicle when the front tires reach the edge of the bed or lumber if used. Verify clearances to the closest soft and hard components. Record on Data Sheet A4. 4.4.2 Massoit Bump at 15 mph. 4.4.2.1 See GM Testing Sta
30、ndards for specifics on Massoit Bumps. 4.4.2.2 Repeat inspection per 4.1.2.7. Record any observations on Data Sheet A4. 4.4.3 Return to the Garage Area. 4.5 Post-Test Inspection. Conduct a four-wheel alignment check, if required. 5 Data 5.1 Calculations. 5.1.1 Ramp angle. 5.1.2 Determine ramp angle.
31、 5.2 Interpretation of Results. Not applicable. 5.3 Test Documentation. Record pertinent test results on the supplied data sheets as specified in this standard. Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permi
32、tted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW16055 Copyright 2013 General Motors Company All Rights Reserved November 2013 Page 4 of 9 6 Safety This standard may involve hazardous materials, operations, and equipment. This standard does not propose to address all the safet
33、y problems associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 7 Notes 7.1 Glossary. Ballast/Ballasting: Refer to GMW15445, Vehicle Ballasting Proce
34、dure. Hard Components: Those made of metal, hard plastic, i.e., oil pans, pipe, etc. Hook Types (for use with towing equipment): Refer to SAE J1142 for a sketch of each hook type. Grab Hook: A hook contoured to grasp a specific size chain link. Verify that hook throat is correct match with chain lin
35、k size. J-Hook: A large 0.15 m to 0.30 m (6 in to 12 in) shank) J-shaped hook. R-Hook: A special hook used only by vehicle manufacturers and shippers. Not used by the towing industry. T-Hook: A hook designed to engage and disengage a slot only when rotated from its expected line of action. J-K: Fron
36、t and Rear rocker to ground dimension. Luggage/Cargo: Refer to GMW15474, Definitions and Terminology Vehicle and Component Mass. MCMR (Maximum Curb Mass Rating): Refer to GMW15474, Definitions and Terminology Vehicle and Component Mass. Pitching: A fore-and-aft rocking motion of a vehicle about its
37、Y-axis. Safety Chain(s/Cable(s): Chain(s)/cables(s) used to connect the towing and towed vehicles as a secondary coupling system. Soft Components: Flexible surfaces, i.e., some air dams. Towing Instructions: Latest copy of the GM Towing Information or test engineer direction. 7.2 Acronyms, Abbreviat
38、ions, and Symbols. FT Front GAWR Gross Axle Weight Rating GVMR Gross Vehicle Mass Rating GVWR Gross Vehicle Weight Rating MPG Milford Proving Ground RR Rear 8 Coding System This standard shall be referenced in other documents, drawings, etc., as follows: Test to GMW16055 9 Release and Revisions This
39、 standard was originated in July 2008. It was first approved by Global Aftersales Engineering in October 2008. It was first published in October 2008. Issue Publication Date Description (Organization) 1 OCT 2008 Initial publication. 2 NOV 2013 Five year refresh; removed references to GMNA regional d
40、ocuments and test facilities. (Global Aftersales Engineering) Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW16055 Copyright 2013 Genera
41、l Motors Company All Rights Reserved November 2013 Page 5 of 9 Appendix A: Data Sheets Data Sheet A1: Instrument Calibration Report No.:_ Test Procedure No.:_ Test Date: _ Instrument Description Instrument Number Calibration Date Next Calibration Due Date 1 4-Wheel Vehicle Scale 2 Front Wheel Aligne
42、r (if required) 3 Rear Wheel Aligner (if required) 4 Tire Pressure Gauge 5 Protractor (Angle or Pitch Gauge) 6 Tape Measure (Metric) 7 Inside Caliper 152 mm (6 in) 8 9 10 11 12 13 14 15 16 17 18 19 20 Recorded by: Date: (Signature) Copyright General Motors Company Provided by IHS under license with
43、General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW16055 Copyright 2013 General Motors Company All Rights Reserved November 2013 Page 6 of 9 Data Sheet A2: Towed Vehicle Roll Back Method Report No.: Report Da
44、te: Tow Vehicle (4.1.1.1): Vehicle Model: Year: Vehicle No. Bed Model: Description: Manufacturers Published Ramp Angle (4.1.1.2.1): As Tested: Figure A1: Roll Back Ramp Angle If gauge not available, use Scientific Calculator: (Set to “Inv”) Height/Length = Angle (Hit “Tan”) Height Length Equals Angl
45、e Figure A2: Add Lumber If required, add lumber to adjust ramp angle. Lumber added (4.1.1.2.2) _ If gauge not available, use Scientific Calculator: (Set to “Inv”) Height/Length = Angle (Hit “Tan”) Height Length Equals Angle Recorded by: Date: (Signature) Copyright General Motors Company Provided by
46、IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW16055 Copyright 2013 General Motors Company All Rights Reserved November 2013 Page 7 of 9 Data Sheet A3: Towed Vehicle Roll Back Metho
47、d Report No.: Report Date: Test Vehicle: Program: Year/Model: Vehicle No.: Body Style: Description: Observation After Driving Vehicles (4.1.1.3): Height Specifications (4.1.1.5) Heights Specification As Tested Left Right Left Right J at rocker FT K at rocker RR Curb Mass (4.1.1.6) Luggage/Cargo Weig
48、ht: Maximum Curb Weight As Tested Left Front Wheel Right Front Wheel Right Rear Wheel Left Rear Wheel Front Axle Rear Axle Total Manufacturers Lowest Recommended Tire Pressure (4.1.1.7) As Tested Front Driver Side Front Passenger Side Rear Driver Side Rear Passenger Side Recorded by: Date: (Signature) FT = Front, RR = Rear. Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
