Effects of worn front axle suspension components!

Worn front end suspension components = Unusual Tyre wear = Higher fuel consumption.

In this post you will get to know how front end suspension components affect the following parameters!

1. Cause improper front end alignment.
2. Increase tyre wear.
3. Reduce fuel economy and increase operational costs.

Normal Tyre Conditions: 

Gradual tyre wear is normal; flat and even tyre wear is a sign of correct alignment, tyre balance, and proper inflation.

Alignment Purpose:

Alignment compensates for slight normal front suspension tolerance and component wear in king pins, bushings, tire rod ends, steering gear, and springs that sag.

Lubrication:

Regular lubrication prevents or defers wear to these components. Not only it's important to lubricate the front suspension at correct intervals, but it is also very important to use the correct type of lubricant.

Misalignment Indicators:

Tyres with even the slightest edge wear, cupping, or spotty wear are exhibiting signs of misalignment. This misalignment may be a result of either poor alignment settings or worn parts that create a misaligned front suspension.

Tyre Wear:

Heavy, spotty, cupped or irregular tyre wear are signs of components of king pins, bushings, tie rod ends, steering gear, pitman arms, idler arm, shock leakage, or wheel bearings that are out of specification. Below Figure, identify each type tire wear problem.

Energy Savings:

Tyre scrub, a lateral force that pushes the tyre sideways, adds to the rolling resistance of the vehicle. As a result, more energy is required to move the vehicle in its intended path of travel. Tyres are constructed from petroleum stock; therefore, if tyres wear out prematurely, natural resources are wasted.

Balance:

Tyre and wheel balance compensates for static and dynamic unbalance of wheels and tyres. Unbalanced tyres bounce and lose contact with the road. The "heavy side" of the tyre comes in contact with the road and small excessive amounts of the rubber are rubbed off.

Improper Inflation:

Improper inflation, too low or too high, may also result in excessive tyre wear. Underinflating wears out the edges of the tyre and adds to tyre drag. Fuel is wasted due to increased drag. Overinflation wears the tyre in the center. The illustrations below portray road contact and wear patterns when tyres are:

Many heavy truck operators and technicians ignore minor suspension and tyre wear problems. Traditionally, tyre cost has been insignificant to the overall cost of operation. Since the trucking industry has become increasingly more competitive, small incremental costs can begin to reduce an operator's profit margin. Tyre scrub results not only in worn tyres, but also in decreased fuel economy. Technicians must demonstrate to customers superior knowledge of methods that can lower operating costs.

©️ 2019 A2s Truckinfo.

Importance of Rear Axle Alignment on heavy Trucks

A properly aligned front end has long been established as a necessity for long tyre life, handling ease, and driving safety, as well as a factor in achieving optimum fuel economy

However, until recently, little attention has been focused on the alignment of the rear axle. A misaligned rear axle may result in:

a) Reduced tyre life;
b) Difficulty in driving;
c) An unsafe vehicle;
d)Less than optimum fuel economy.

According to our studies, "It has proven that 80% of  Multiaxle trucks are operating misaligned, and over 90% of the trucks they pull have serious alignment problems." The majority look like those in Figure 2.

A misaligned rear axle causes excessive tyre-to-road drag and creates undesirable lateral forces.

Figure 1 illustrates correct tandem axle alignment.
Figure 2 illustrates some possible axle alignment conditions.

Even new trucks need rear axle alignment. 

Studies also cite that up to 70% of new vehicles need some form of rear axle alignment. In a study of around 1500 trucks, those with proper rear axle alignment vehicle having 10-20% more tyre life and having fuel saving upto 5%.

According to recent studies conducted, Additional real axle drag and scrub contributes to even more fuel loss and decrease in tyre life. "Sixty percent of steering axle tyre wear is caused by drive axle misalignment."

All heavy trucks and trailer units should have their rear axle alignment checked and adjusted periodically or when any abnormal tyre wear appears. Rear axle alignment should be checked after any collision repair. Minor shifts in the frame-to-suspension mounts may cause significant shifts in both front and rear axle alignments. To align the front axle will only fix half the problem.

Below figure illustrates various effects on fuel consumption. Drag and tyre rolling resistance accounts for the single largest segment of fuel consumption - 42.2%. Any action taken to reduce rolling resistance, such as proper alignment, can and will reduce fuel consumption.

It is possible for a given truck to have reciprocal rear axle misalignment conditions. If this were the case, it may not exhibit any poor driving characteristics. However, tyres will still wear and fuel economy will be decreased.

Tyre Wear usual suspects:

Rear axles usually have little or no camber and toe requirements.

Heavy trucks rear axles use no caster alignment correction.



©️ 2019 A2s Truckinfo.