Understanding Camber

Camber, measured in degrees, is the amount the wheel is tilted at its top, in or out, from a vertical position.  Outward tilt of the wheel is positive camber; inward tilt is negative.  Originally, trucks were designed with a small positive camber.  In such a design, the load could be more effectively placed on the heavier inner wheel bearing, and a negative camber was avoided as axles sagged and parts wore as a result of normal operation.  It also reduced side thrust on the kingpin.  The amount of camber has been decreased considerably on trucks over the past few decades because stronger axle materials have become available and suspension designs have been improved as well as the introduction of radial tires.

Along with the introduction of more powerful engines came signs of abnormal tire wear.  Right front tires have been found to cup and wear on the outer edge.  The cause of this is a combination of positive camber and the effects of increased engine torque.

The engine’s crankshaft rotates counter-clockwise when viewed from the driver’s seat. The torque reaction on a heavy duty truck can transfer up to 2,000 lbs. from the left front wheel to the right when starting out.  When this transfer takes place, the centerline of the tire will offset from the centerline of the rim by as much as ¾ of an inch.  After the vehicle gets up to speed in low gear, there is an instantaneous release of torque at the moment the clutch is disengaged snapping the tire back and bringing the two centerlines together once again.  This snap-back is the cause of the cupping on the outside of the right front tire.

Adjustment to correct camber specifications requires setting the right front wheel at -1/8° camber – straight up and down.  In this way the tire will be planted square on the road when it’s torque loaded.  The left front wheel should be set at -1/4° positive camber.  These settings will provide maximum tire life and better drivability.

Dis-similar Camber Correction
(To Decrease Right & Increase Left)

To make a camber adjustment, the axle is fitted with clevises on both the right and left sides – left side outside the spring seat, right side inside the spring seat.  A hydraulic ram is then used between the clevises, physically correcting the axle to the desired camber settings.  Another ram is then placed outside the right clevis to reduce the camber in the right wheel.  Never spot-heat an axle in order to correct it; high temperature will remove the strength it was given by heat treatment.

Bee Line offers a 5 day course on Alignment.  The course includes 8 hours of classroom time and 32 hours of hands-on training.  On-Line Registration

Understanding King Pin Inclination (KPI) / Steering Axis Inclination (SAI)

KPI / SAI is the inward tilt of the king pin, or ball-joint / bearing plate - at the top. The KPI / SAI angle and camber are related. The principle purpose of KPI / SAI is for proper component load distribution and to position the tire so that the KPI / SAI and camber meet at a common point where the center of the tire contacts the road.

Most front suspensions carry a king pin / ball joint / bearing plate that is inclined inward at the top.  This angle has the effect of placing the turning point at the center of the tire instead of toward the inside of the wheel. The result is more stable steering.

Combining camber angle and KPI / SAI angles is referred to as included angle. Camber is built into the wheel by forming the spindle with a downward tilt. KPI / SAI angle is built into the end of the axle. While the two angles are interrelated, it is best to measure them separately. (This is necessary in order to determine a bent spindle, king pin or damaged suspension connection components.)

When the KPI / SAI relationship is correct, the weight of the vehicle causes the front wheels to automatically straighten out after a turn. As the wheel turns, the end of the spindle rises and falls. One side of the vehicle is raised as the front wheels are turned to the right or the left and is lowered when the wheels are in the straight ahead position.

Why Measure If You Don't Correct??

Bee Line recognizes that in addition to allowing the measurement of critical alignment angles, it is important that alignment equipment allows you to correct all out of tolerance alignment angles. After all, what good is it knowing the truck is out of alignment if you cannot correct the problems? This means not just correcting toe and/or rear tracking, but also correcting camber and caster. For those who want their truck aligned should expect that the shop can not only measure the alignment angles, but also have the proper equipment to correct any errors found.

With the ability to correct toe, rear tracking, and camber, Bee Line allows you to fix the #1, #2, and # 3 causes of tire wear and increase fuel efficiency. Also, with the ability to easily correct caster, vehicle handling can be improved increasing driver comfort and safety.

The Bee Line Advanced Aligner Runway machine and our alignment tooling is designed to allow a shop to perform all necessary alignment corrections. The machine places the truck at a comfortable working height, either in a pit or above ground. It allows you room to make adjustments to not only toe and tracking, but also camber and caster. It also allows you easy access to the vehicle's front end to inspect for worn front end parts and to perform necessary measurements and corrections. There is no fixed beam or equipment hindering access or making it difficult to work on the vehicle.

Bee Line's patented camber tooling can correct out of tolerance camber on all axle sizes and also correct any axle twist. The floating beam system is designed to be easily attached to the vehicle axle for corrections and removed and placed out of the way when the correction is finished. Special Bee Line fixtures also allow easy removal and replacement of caster wedges.

Bee Line has long been a proponent of the benefits of camber correction. We know that our patented camber correction equipment, along with our many years of experience and extreme accuracy allow users of Bee Line equipment to perform camber correction safely and accurately. Camber correction, as part of a "Total Vehicle Wheel Alignment", allows vehicle owners to achieve maximum tire life and fuel efficiency.

LC7500 Computer Alignment System

A Proven Way to Battle High Fuel and Tire Prices

Although Wheel Alignment is often overlooked on the preventative maintenance programs in the trucking industry, more importance is increasingly being placed on the cost savings and handling characteristics of routine complete alignments. Fleet executives are continually putting more emphasis on maintaining skilled drivers by performing alignments, which create considerable fuel and tire savings while improving drivability.

Studies continue to find that only setting the toe and tracking on vehicles is not a complete solution. Camber is recognized as a major contributor to tire wear and caster is a major contributor to suspension life and drivability.

Bee Line is a leading manufacturer of equipment that MEASURES AND CORRECTS caster and camber - resulting in TOTAL wheel alignment. We manufacture heavy duty truck frame correction equipment in addition to the alignment equipment, thus providing a complete solution. While vehicles continue to get lower to the ground and axles continue to get stronger, Bee Line produces new products to keep up with these trends. Bee Line systems are designed to fit each shop’s specific needs and expand to accommodate changing conditions.

Rear Axle Gauging

What are the leading wheel alignment factors?

Wheel alignment is the positioning of the interrelated angles of a front suspension, rear axle or housing to give the maximum amount of tire life, steering ease, steering stability and increased life of suspension components. Improper wheel alignment results in excessive or irregular tire wear, hard steering, poor drivability and premature failure of suspension parts. Several alignment factors must be considered to achieve proper wheel alignment. The top four factors are toe, tracking, camber and caster.

Toe and tracking are the two most critical alignment settings for front end tire wear. Bee Line gauging equipment incorporates lasers to measure for proper steer axle toe. Toe is adjustable to reduce tire wear and shimmy in the steering wheel. Excess or too little toe will make the front wheels fight each other, resulting in feathering, diagonal wear or excessive shoulder wear.  An out-of-toe condition leads to rapid tire wear. Tracking misalignment also will cause inside outside wear of the steer tires. Tracking, or thrust, is gauged relative to the vehicle centerline.

Camber and caster are the third and fourth most critical alignment settings for front end tire wear. Camber — the inward or outward tilt of the top of the wheel — is important for several reasons. Its main purpose is to keep the tire flat on the road while the vehicle is loaded and in motion. If camber is excessive, it will create shoulder wear. Caster is the forward or rearward tilt of the king pin. Extreme caster settings can cause handling problems, leading to driver fatigue.