Save Money on Fuel By Fixing Semi

Jan 13, 2024

Anyone who's sat behind the wheel of a car or truck — regardless of the vehicle's size — and felt the steering wheel shake as they drove understands the fundamental problem of vibration. Vibrations on trucks — in addition to making the driver's hands go numb — can cause various issues.

Drivers may struggle with low fuel mileage, excessive wear on moving parts and even premature breakdowns. How can reducing or eliminating semi-truck vibration problems help trucking companies save money in the long run?

Vibrations on trucks can appear in many different forms, but most are in one of three orders. The orders of vibration indicate how many shakes the driver feels per revolution of the drive shaft. First-order vibrations mean a single shake per rotation, with second-order vibrations indicating two shakes.

Most of these vibration orders are tied directly to the drive shaft. First-order vibrations could indicate the truck has drive axle or drive shaft problems or something connected to and rotating at the same speed as the drive shaft is out of balance. More frequent shakes could indicate more significant issues.

Second-order vibrations often indicate issues with the vehicle trim height, the powertrain mounts or the U-joints. Problems with the drive shaft — such as twists, improper angles or damage — could cause second-order vibrations.

Third-order vibrations on trucks — where the driver experiences three or more shakes per rotation of the drive shaft — usually indicate significant issues. They should address such a vibration as soon as possible.

Drivers will be the first line of detection regarding vibration since they spend the most time in the driver's seat. Companies concerned about vibration could also consider adding fleet telematic sensors to their trucks designed to detect shakes that might be out of the ordinary. Vibrations don't always occur at consistent intensity, so catching them can be challenging for those only relying on driver reports. These sensors can fill in the information gaps and make it easier to spot minor problems before they sideline the truck.

There are a host of different things that can cause semi-truck vibration problems and troubleshooting starts with determining the source of the vibrations. Feeling them in the steering wheel usually indicates an issue in the front of the vehicle. If the truck is moving from side to side — also called a lateral movement — it could mean problems in the front. Vibration in the seat or radial ‘hopping’ style movements indicate issues in the back.

Drivers and mechanics will also need to determine when the vibration occurs. Is the truck vibrating while accelerating or climbing an upward grade or do the problems worsen when the driver applies the brakes or makes a turn?

Sometimes, the causes of vibrations on trucks are simple. An unbalanced tire or a loose lug nut might sound like a small problem, but when dealing with a vehicle that weighs up to 80,000 pounds when fully loaded, minor issues become magnified. Take the time to check the alignment and balance on each tire.

Vibration when drivers press the clutch pedal or shift gears could indicate an issue with the gearbox or the shifter. The clutch assembly might be worn out or the maintenance team might just need to pull it out and clean it. While it might not seem connected, it could also indicate issues with the starter motor, which could leave the truck stranded on the side of the road if it fails.

If vibrations occur during acceleration or when driving uphill, inspect the transmission, torque converter and driveline. The brakes might be the culprit if it happens when slowing or stopping. Unbalanced or out-of-round brake discs or drums can cause the tires to shake whenever the brakes are depressed. Suspected brake issues should be addressed as soon as possible because they also represent a significant safety concern. Shaking while accelerating could also be the fault of the truck's suspension, which merits inspection.

If drivers are dealing with vibrations during turns, it could indicate loose front-end parts. If the vehicle only vibrates when carrying a load, it could indicate issues with the cargo, such as balancing. Drivers should avoid idling their trucks for long periods, but vibrations while idling could indicate a timing or misfire issue with the engine that will need the maintenance crew. This list is not exhaustive but may help troubleshoot semi-truck vibration problems.

Vibrations on trucks are more than just a minor inconvenience. Long-term exposure to full-body vibration for drivers can cause various health problems. 50% of surveyed truck drivers reported experiencing low back pain, while more than 30% reported issues with the neck and shoulders. Knee, wrist or forearm, ankle, feet and leg pain round out the report.

Vibration syndrome — caused by prolonged exposure to perpetual vibration — can negatively impact circulation. Symptoms can occur quickly and studies show patients can develop advanced symptoms in less than a year.

These vibrations aren't good for the trucks, either. Excessive vibrations on trucks cause unnecessary wear and tear, leaving owners and companies footing the bill for increased maintenance and repairs. Choosing to ignore the problem or not addressing it quickly enough could lead to equipment failure.

Many of the signs of wear might not be visible on a cursory inspection, but drivers will begin to feel the effects. Excessive wear can reduce fuel economy, leaving them to pay more at the pump. By getting rid of semi-truck vibration problems, drivers can experience improved fuel efficiency because it uses less energy.

There are a million and one things that can cause semi-truck vibration problems and ignoring them won't make them go away. Driving a truck that vibrates badly can cause injuries to the drivers and costly damage in the long run.

Addressing vibrations on trucks might seem like a hassle, but it will prevent these small problems from causing larger ones or causing equipment failure that leaves the vehicle and its cargo stranded on the side of the road.

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