Changes in snowplow-mounting guidelines
Sep 1, 2006 12:00 PM, BY RICK WEBER
GENERAL MOTORS has made the most significant changes in the manufacturers' snowplow-mounting guidelines for the 2007 model year.
GM has switched to a coil-over shock suspension, rack and pinion steering, and a stiffer frame as part of its package in an all-new design.
“By going to the stiffer frame, it gives us a better ability to isolate the passenger compartment from noise and vibration and allows us to tune our suspensions to give us the ride we want,” says Dan Tigges, product manager for fleet and commercial operations. “The coil-over shock gives you better ride and handling. The rack and pinion gives you a better on-center feel, a more linear feel to the steering.”
Tigges says that with an all-new design, the mounting points and attachments have changed slightly because it's not the same front-end sheet metal and bumper and grill.
“The sheet metal is a styling issue to make the truck an all-new vehicle,” he says. “It also helped with the aerodynamics of the vehicle to help fuel economy and the perceived quality of the vehicle — the fits, finishes, and gaps are much tighter, giving it a much more refined quality look.”
GM's Steve Strine adds that starting in November, the company will produce only two LD models approved for the snowplow prep package — 10903 and 10703 — and the 25 Series won't be produced until the first quarter of 2007.
“The current production vehicle will be built into the '07 models, so we'll be running the old and new pickup at the same time.”
Dodge has made no major changes to its '07 package. But David Donnelly, electrical synthesis engineer for the new commercial vehicle team, says an explanation of the '06 changes needs to be made because a lot of snowplow manufacturers were caught off-guard a year ago.
The '06 model year featured TIPM (Totally Integrated Power Module), “a glorified fuse box” that controls the exterior lighting.
“If you open it up on your hood, you won't see any relays,” he says. “It's all circuit board. We have left some fuses for customer serviceability. The output of the lights is controlled by field-effect transistors with the current mirror, meaning they monitor the current on the lines to tell whether you have an open or short circuit.
“The downside is that if you add additional loading like lights or a plow hookup and want to run the vehicle's turn signals, plus the turn signal on the plow, that puts the current over the allotted limit. The vehicle senses there is an over-current situation, which typically means a resistive short, and it turns the circuit off. So the big thing plow manufacturers need to be aware of — and we've contacted quite a few of them — is that they need to add relays into our system.”
Installers typically have tied into the turn-signal wire and spliced that into their additional turn signal. Now they need to run that to the coil side of the relay and basically use that as a sense line, and then run the main contact side of the relay from the direct battery — a fused wire from the battery. The other side of that goes to their turn light.
Ford's '06 models will carry over to '07. There are major changes in store for '08, but the marketing department has not yet made a decision on how to release them.
The following list is for quick reference only. For a comprehensive list of the specific guidelines for each model, refer to the body builders book published by the truck manufacturer.
GM recommends that when a snowplow is mounted on a vehicle, only one passenger should accompany the driver. More than one passenger may exceed front Gross Axle Weight Ratings.
Prior to installing a front-mounted snowplow, the following process should be followed and necessary information obtained:
Establish vehicle curb weight.
Establish chassis manufacturer's front and rear axle weight ratings.
Chevrolet and GMC truck dealers can provide availability, specifications, GVWR, and Front and Rear GAWR. For vehicles already built, this information can be found on the certification label installed on the driver's door/frame or provided on the cover of the incomplete vehicle document.
The following information should be obtained and provided by the manufacturers of snowplows and salt spreaders:
Specifications, weights, and center of gravity data.
Vehicle installation guidelines and instructions.
Calculation of weight distribution for the front and rear axles.
The loaded vehicle with driver, passenger, aftermarket accessories, snowplows, spreader, and cargo must not exceed the GVWR, and Front and Rear GAWR.
In addition, the completed curb weight vehicle, with all installed aftermarket accessories, snowplow, and spreader, and with 400 lb distributed in the driver-passenger area of the vehicle, must have a center of gravity that is located within the trapezoid formed by the coordinates A, B, C, D, H1 and H2, plus it must be to the rear of vertical line E and forward of vertical line F as defined in the Allowable Center of Gravity charts. If the center of gravity does not fall within the specified trapezoid, ballast weight may be required to shift the center of gravity until it falls within the specified trapezoid.
The snowplow manufacturer and the installer of the aftermarket equipment should determine the amount of rear ballast required to ensure that the vehicle, with the attached snowplow and aftermarket equipment, complies with the Allowable Center of Gravity Trapezoid and the resulting front and rear weight distribution ratio as defined in the Allowable Center of Gravity Charts published in the GM manual.
The use of rear ballast weight may be required to prevent exceeding the GAWR of the front axle. The use of rear ballast weight may be required to ensure that the center of gravity location of the completed vehicle, with the attached snowplow and other installed equipment, complies with the Allowable Center of Gravity Trapezoid and the resulting front and rear weight distribution ratio, even though the actual front weight may be less than the GAWR of the front axle. In either case, the rear ballast weight should be securely attached in the cargo box or behind the rear axle of the vehicle in a manner that prevents it from moving during driving and stopping.
To help avoid personal injury, refer to Z-height setting procedure before adjusting torsion bars. If torsion bars are adjusted for aftermarket equipment, be sure to return them to specification when the equipment is removed. Otherwise, a front shock absorber may dislodge and damage a front brake line. This could result in an accident when minimum stopping distances are required.
Minimum recommended equipment for the F-150: regular cab 4×4, 144.5" wheelbase, 8' pickup box; or SuperCab 4×4, 163" wheelbase, 8' pickup box.
Snowplow prep package (option code 63A) includes FGAWR upgrade to 4300 lb (4300 lb spring rating).
Heavy Duty Payload package (option code 627) includes: 8200-lb GVWR; 4050-lb FGAWR (4050-lb spring rating); 4800-lb RGAWR (4900-lb spring rating); rear axle capacity upgrade to 5300 lb and 10.25" diameter ring gear 4.10 ratio, limited-slip not included but available; 17"×7.5" J 7-lug steel wheels; LT245/70R×17D BSW all-season tires (5); 5.4L, 3-valve V8 engine, 4R75E automatic transmission; Super Engine Cooling (1.42" core thickness); auxiliary transmission air cooler, oil-to-water increased to 9-channel/18-plate; battery upgrade to 72 amp-hr/650 CCA; fuel tank (35.7-gallon capacity).
Snowplow weights (maximum recommended):
Regular Cab 695 lb (645 lb removable plow assembly plus 50 lb permanently attached hardware).
SuperCab 535 lb (485 lb removable plow assembly plus 50 lb permanently attached hardware).
These snowplow weight limits are based upon a vehicle built with maximum buildable Ford option content, driver plus one front seat passenger, 150 lb each, 800 lb of ballast weight rearward of the rear axle, and additional assumptions for commercially available snowplow assembly weights and mounting location.
The vehicle must not be operated when overloaded. A vehicle is overloaded when the weight of the completed vehicle with aftermarket equipment installed, plus driver, passengers, and cargo, exceeds either the FGAWR, RGAWR, or GVWR established by Ford Motor Co and displayed on the Safety Compliance Certification Label.
The addition of ballast weight placed rearward of the rear axle may be required to prevent exceeding FGAWR, and provide good vehicle braking and handling. The ballast should be attached securely to the vehicle with consideration for the normal driving dynamics of snowplowing and occupant safety in accidents.
For Ford completed vehicles of 10,000 GVWR or less, the weight of permanently attached aftermarket equipment must not exceed the Total Accessory Reserve Capacity displayed on the Safety Compliance Certification Label to maintain the compliance representation that came with the Ford-built vehicle. Exceeding TARC will require recertification. This applies only to the permanently attached equipment, such as the snowplow frame mounting hardware, and not to the removable portion of the snowplow blade assembly.
Front end wheel alignment (toe) and headlight aim may require readjustment after installation of snowplow equipment. Failure to reset front wheel alignment may cause premature uneven tire wear. If required, reset to chassis manufacturer's specifications found in the Ford Shop Manual.
Installation of any inductive load devices such as electric motors, or electric clutches for clutch pumps, must not be connected to Ford vehicle wiring or fuse panels. Power for such devices should be taken directly from the battery or starter motor relay power terminal.
Control of these devices should be achieved via relays.
No direct current path should exist between Ford vehicle wiring and the installed load that is not filtered by the battery. These recommendations are intended to eliminate or minimize any induced reverse voltage into the Ford circuitry.
The loaded vehicle, including all aftermarket accessories, the snowplow system, passengers, and cargo, must not exceed the gross vehicle weight (GVW), front or rear gross axle weight (GAW) ratings specified on the Safety Compliance Certification label located in the driver's side door opening. The empty truck with all permanently attached accessories and snowplow components must not exceed 62% of its total weight on the front axle to comply with FMVSS/CMVSR 105 Brake Certification. Permanently attached snowplow parts are those parts not easily removed when the blade is removed. The permanently attached parts are: subframe, hydraulic pump, hydraulic lift cylinder, lamps, wiring, snowplow controls, etc.
If the front axle loading exceeds either 62% of the empty truck total weight, or the front GAWR, ballast compensating weight must be securely attached at the rear of the truck to bring front axle weight within weight specifications.
Notes for heavy-duty snowplows:
At any time, the maximum number of occupants in the truck must not exceed two.
Under any circumstances, vehicles should not exceed GVWR (Gross Vehicle Weight Rating), front or rear GAWRs (Gross Axle Weight Ratings).
Snowplow prep packages are not available with Sport (AAG) package.
Cargo capacity will be reduced by the addition of options.
Ballast should be securely attached inside the box at 9” from the rear tailgate for pickups.
The total weight of permanently attached hardware should not exceed 125 lb.
Max snowplow weight should not exceed values for models shown in this section.
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