When researching for an article on front bumper extensions, more questions were created than facts were found. And they were only about front tow hooks and tow eyes. Sentence 12.3.5* Tow Hooks in the National Fire Protection Association’s NFPA 1901 Standard for Automotive Fire Apparatus states: “Front and rear tow hooks or tow eyes shall be attached to the frame structure to allow towing (not lifting) of the apparatus without damage.” That is short and simple–probably as brief as most purchasers’ specifications as noted below. There is a bit more to front-towing provisions that purchasers should consider.
Alissa McGlone, marketing manager for HME Ahrens-Fox, put me in touch with David Rider, director of product management & development for HME, who answered some questions on front-towing provisions, the differences between hooks and eyes, how and why they’re located, and how purchasers should specify them.
Do tow hooks and tow eyes have different “weight” ratings? Generally, no, because they have the basic job of providing an anchor point to attach a tow cable. They are only as stout as what they are bolted to and the strength of the fasteners. NFPA 1901 stipulates they are for towing only and not lifting the apparatus.
Eyes and hooks can be mounted on top of a bumper, underneath it, or through the front of it. Are mounting locations job-specific? Typically, tow hooks under the bumper are the standard. Sometimes it’s more about aesthetics than function with hooks being more hidden and eyes more in the open. They are there if needed, but typically play no other role. Tow eyes through the bumper, or above or below it, might be used as anchor points. In large fleets they might be specified to be compatible with a fleet-owned wrecker.
When a front bumper is extended (e.g., hose troughs or front suctions) does the length of the extension have a bearing on the type and location that hooks and eyes can be used? It sure does. A lot has to do with the bumper extension, how it affects the angle of approach, and how much “stuff” is on the front bumper. If you have a short or no bumper extension, then tow eyes through the bumper, or hooks under the frame rails, are really your only choice. The longer the extension the more choices, but it affects your angle of approach. It’s best to let the chassis manufacturer design the components for the intended purpose.
Are there recommended specifications for which one to use? Not really. It’s what works best for the fire department. On an engine, tow hooks are probably fine. On a rescue, pumper-rescue, or aerial where they may need to act as an anchor point, tow eyes that are accessible and easier to rig may be a better choice. Tow eyes are also easier to rig as an anchor point.
When a bumper is extended, is there a recommended specification that purchasers can use to ensure the tow eyes or hooks will work as intended? Many departments only specify if they want hooks or eyes and whether they are painted or chromed. It is imperative purchasers inform the manufacturer exactly what the intended purpose is so the manufacturer can adequately design the installation. The position of under-the-bumper extension, through the front bumper or up, through the gravel shield is contingent upon function.
On extended bumpers, are tow hooks and eyes attached directly to the frame rails better? It depends on the frame extension. If it is as robust as the frame rails and engineered properly then on the extension is OK. Otherwise directly to the frame rails is the best. Not all bumper extensions are created equal. Some manufacturers require the apparatus to be towed using the front axle, not the bumper extension. It’s best to ask the manufacturers. I have seen some pretty snazzy bumpers that have zero structural integrity. Typically, the more complex the extension the weaker it is.
Do you have any words of wisdom about front tow eyes and tow hooks for purchasers? Honestly, we don’t care. Just don’t ask for something that physically will not work; 12 inches equals a foot. The bumper can get really busy, really fast.
Rider’s statement “Just don’t ask for something that physically will not work” makes sense. Purchasers should be upfront and honest with vendors by telling them exactly what the eyes or hooks are expected to accomplish–especially on an extended bumper. That way the vendor can design and build it appropriately. It would be embarrassing if a tow truck attempts to pull a rig out of a ditch and ends up ripping off its bumper. An extended bumper with tow hooks or eyes on a commercial chassis might have to be reinforced more so than on a custom fire chassis. Vendors should be equally forthright with purchasers by explaining what is available as well as the advantages and limitations of each.
Tow eyes and hooks are often ambiguously described in fire apparatus purchasing specifications. Randomly selected purchasing specifications found online follows:
“Two (2) heavy-duty tow hooks, painted to match the frame components, shall be installed behind the front bumper in the forward position, bolted directly to the side of each chassis frame rail with grade-8 bolts.”
“Two (2) 3/4” thick stainless-steel tow eyes shall be securely attached to the front chassis frame rails to allow towing (not lifting) of the apparatus without damage. They shall be mounted down below the bumper/cab.”
“There shall be two front tow eyes with 3-inch diameter holes attached directly to the chassis frame, accessible below the front bumper. The front tow eyes shall be painted to match the color of the chassis frame.”
The most “informative” specification found is: “Two (2) chromed steel tow hooks shall be installed under the bumper and attached to the front frame members. The tow hooks shall be designed and positioned to allow up to a 6,000-pound, straight, horizontal pull in line with the centerline of the vehicle. The tow hooks shall not be used for lifting the apparatus.”
It may not be prudent for a fire department to write their own specifications for front-towing provisions on any apparatus. Coordination between the fire department and vendor(s) is imperative. It may be a good idea to query multiple vendors before writing purchasing specifications. Do you know if a forged or plate steel tow eye is better? Do you know if the towing device you specify is adequate to tow your pumper, or your rescue, or your much heavier aerial tower? Did you know how you’re supposed to tow your rig before you write specifications? Did you ask?
If you write the specs and the vendor complies and there’s a problem down the road, it could be your problem and not the vendor’s. Good luck.