Mobilize today for the DOT's CSA Enforcement Program. Act now with a proactive safety management philosophy. The goals of this blog are to provide information, insights and know-how on being safe, mitigating exposures and risk, and maximizing control of losses. Email me at john(at)part380(dot)com. Thank you for visiting.
Fact: tires fail. When a truck tire fails, especially a front tire, it can lead to loss of control and a crash or rollover.
Causes of Tire Failure
One study for the National Highway Traffic Safety Administration (NHTSA) by the University of Michigan Transportation Research Institute (TRI) found the main causes for tire failure include:
Road hazards— 32 percent
Maintenance/operational factors— 30 percent and
*Overdeflected operation— 14 percent.
*Overdeflected operation means a tire that was operated either underinflated or overloaded or a combination of the two, leading to tire failure.
The study noted, “Tire failure and debris . . . are rarely the cause of a truck crash, factoring in less than 1 percent of all such accidents.” New and retreaded medium truck tires have about the same failure rates and modes.
Driver Response to a Tire Blowout
The driver must always control the vehicle. If a tire blows out, the driver may or may not hear it, but will feel the blowout either in the steering wheel, if the front tire is flat, or in the seat, if one of the “drives” goes flat.
Safety experts recommend in the case of a sudden tire failure, that the driver SHOULD NOT BRAKE and SHOULD NOT TAKE THEIR FOOT OFF OF THE THROTTLE.
In a tire-failure situation, drivers should instead mash down on the throttle for such duration as to regain control of the vehicle.
This seems counterintuitive, but makes sense. Loss of a tire can affect steerability and braking or suddenly slowing down with a flat tire can result in the vehicle pitching forward, resulting in less control.
Once control of the vehicle is regained, the driver can ease off and guide the vehicle in a controlled manner.
This technique assumes the driver is not running up against the governor and has some engine power in reserve. Another study by the NHTSA noted that there are no truck tires rated over 81 MPH. The study cited high speeds and a lack of maintenance as contributing factors in fatal truck tire blowouts.
In a truck tire rapid air-loss situation, drivers should STOMP on the throttle and STEER to a stop.
Check tire pressures frequently. A tire gauge is better than a tire thumper.
Visually inspect tires for wear or damage on a daily basis.
Never make a habit of running RPMs up against the engine governor. Keep a little power in reserve for emergencies.
Always drive at reasonable speeds, based on the condition of the vehicle and tires, road conditions and weather, and type of load. Never exceed speed limits or safe speeds for driving conditions.
Remember, the goal is to arrive safely.
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Here’s a tire inspection quick tip: use a gasket (or seal & bearing) puller tool to remove debris found in the grooves of the tire. Stones or bits of metal or glass can start working their way in the tire and need to be removed before working their way down and causing greater damage.
A gasket puller makes quick and easy work of tire debris removal.
A gasket puller can be found at most automotive part stores for about $10 or less. Get the most of out your tire investment by frequent inspections and professional care.
The gasket or seal puller hand tool.
Use the gasket or seal puller when doing a pre-trip, en-route or post-trip inspection, while waiting at a dock or anytime after driving on areas where road debris is found.
The CSA Tire Inspection video starts with the now standard boilerplate legal disclaimers, followed by a musical intro of a turquoise blue Michelin truck, and self-introductions by Kevin Rolling, of the Tire Industry Association, and Doug Jones of Michelin, NA. At 2:45 there is an introduction to CSA (DOT’s regulatory enforcement methodology) and Capt. Douglas Shackelford (North Carolina State Highway Patrol) tells us he will talk about the “visual inspection components” to avoid inspections.
CSA created a new Safety Measurement System (SMS) for both driver and company. Under CSA, individual road violations are assigned a “severity rating” that ranges from one to ten, with ten being the most severe and the most likely to cause an accident.
Items that are required to be inspected under Part 393 for safe operation prior to each trip include:
– Lamps, Reflective Devices and Electrical Wiring
– Glazing & Window Construction
– Fuel Systems, including: Compressed Natural Gas Fuel Containers and Liquefied Petroleum Gas Systems
– Coupling Devices and Towing Methods
– Miscellaneous Parts and Accessories including: Tires, Windshield Wipers, and Rear Impact Guards
– Emergency Equipment
– Protection against shifting and falling cargo, including specific securement requirements by commodity type
– Frames, Cab and Body Components, Wheels, Steering and Suspension Systems
Capt. Shackelford, “For purposes of this video, we’re going to focus on tires. So let’s look at the federal regulations for tires.”
Feeling the sidewalls for bulges and defects.
Feeling the face or crown of the tire for damage by laying hand flat on tire and sliding it across the face.
Tires Part 393.75: No motor vehicle can be operated if any tire exhibits the following conditions:
– Exposed body ply or belt material through the tread or side wall
– Tread or sidewall separation
– Flat tire or a tire with an audible air leak
– A cut where the ply or belt material is exposed
These are generally cited as Out-of-Service (OOS) conditions.
Exception: An under 3/8 inch bulge on the sidewall, if accompanied by a blue repair triangle (no more than two repair patches) is acceptable. Use a “bulge gage” to measure the height of the bulge, if in doubt.
Lead tires (steering tires, converter dollies for semi-trailers and steer axles on full trailers ) must have at least 4/32s tread depth at any point on any major groove expect where tread wear indicators or stone ejectors are located. All other tires must have 2/32s inch in every major groove of the tire.
If tread depth is under the limit as established by Part 393.75, then the driver will be cited for a violation and assessed points under CSA. However, the vehicle will be placed out of service if the tread depth is below the limit set by the Commercial Vehicle Safety Alliance (CVSA).
The vehicle is OOS, if tread depth is under specification at any two adjacent grooves.
The decoupling groove at the shoulder is not a major groove. Other terms for this tire feature include: “shoulder wear protector” or “defense groove” or “pressure distribution groove,” depending on the manufacturer.
If a tire is out of specification, then this is a citable violation (ticket-able) but not an out-of-service (OOS) condition.
Insufficient tread in a decoupling groove is not a violation or an OOS condition, if all the major grooves have sufficient tread depth.
Irregular wear (example: tire “cupping” from dry steering) is not a violation or an OOS condition, if all the major grooves have sufficient tread depth.
Missing tread chucks are not a violation or an OOS condition, if all the major grooves have sufficient tread depth and the missing tread material does not expose the ply materials.
Weather checking is not a violation or an OOS condition, if the checking does not expose the underlying material.
FMCSR 393.75(4)(d) says, “No bus shall be operated with regrooved, recapped or retreaded tires on the front wheels.” This is an OOS condition.
A “regroovable” tire is allowed, but not a regrooved tire.
FMCSR 393.75(4)(d) says, “A regrooved tire with a load-carrying capacity equal to or greater than 4,920 pounds shall not be used on the front wheels of any truck or truck tractor.”
Almost all of these conditions carry a “severity rating” of eight points if found during a roadside inspection.
Example: a tire is found during a roadside inspection with less than 50% of inflation as marked on the sidewall. As such an OOS condition exists (as the tire is considered flat and may have sustained hidden “run-flat” damage).
Under CSA, eight points are given for the flat and two additional points for an OOS condition – multiplied three fold for the 0-6 months multiplier resulting an a total of thirty CSA points (the max allowed for any single violation within a CSA BASIC). This in turn, affects the fleet’s CSA “SMS score” and could later result in additional “targeted inspections.”
“Enforcement officers are now equipped with a valuable tool for any fleet we inspect. And since the CSA “Snapshot” is based on real time inspections and data, we know exactly where to look and have complete confidence when identifying violations, improving safety on our nation’s highways.”
Kevin Rolling, “Perform a thorough pretrip and posttrip inspection.”
Doug Jones: “Thanks for watching.”
The inspections performed by a US DOT certified roadside inspector under CVSA guidelines are focused on CRITICAL items. A driver has a duty to thoroughly inspect (and document) not just the aforementioned “critical items,” but all items (as specified by the regulations) on a vehicle and its load.
The “window of opportunity” is the period of time when a part or accessory begins to exhibit poor performance, prior to a repair being made. This is a period of time and/or of deteriorating performance when the part or freight is in a sub-critical condition that will require service or repair.
For example, when laying a hand flat on tire and sliding it across the face or crown of the tire, if one direction feels smooth and the other has sharp edges, then there is a lateral drag problem (edges of the tire are feathering away from the direction of the push), possibly due to excessive, unequal camber, resulting in decreased MPGs.
Irregular wear is an indicator of future trouble.
“Heavy, spotty, cupped or irregular tire wear
are signs of components (king pins, bushings, tie rod ends, steering gear, pitman arms, idler arm, spring sag, shock leakage, or wheel bearings) that are out of specification.”
Always try to always stay out of the tire’s trajectory areas and know when use a tire cage when working around tires. Several years ago, a small child was killed in Michigan watching his father inflate a truck tire.
Learning how to properly read a tire can prevent later breakdowns in critical items, saving time and money, honor and lives.
FINAL TIRE SAFETY WARNINGS
“Flat tires,” according to OSHA, are any tires under 20% of proper inflation. DO NOT re-inflate any flat tires unless you are a properly trained tire technician. Tires over 80 percent of the recommended pressure may be inflated on the vehicle if proper precautions are taken. Flats should be properly inspected to find the cause of the leak. (See OSHA 29 CFR Part 1910.177)
Stay out of the tire's trajectory areas and know when to use a tire cage when working around tires.