4x4Wire

Setting Pinion Angle Correctly

Pinion angle is one of the more important measurements on a lifted vehicle. The wrong angle can lead to vibration and premature failure of U-joints, drive shafts, pinion bearings and even transfer case output bearings.

Types of drive shafts

There are two common types of drive shafts used in 4wd vehicles, standard with one U-joint at each end and CV drive shafts. CV stands for Constant Velocity. CV drive shafts are so named because they have a constant velocity joint at one end, the other end has a single U-joint.

There are two types of constant velocity joints, the double cardan and the caged ball type. The double cardan type is the CV joint with the two U-joints at one end that is so popular with 4 wheelers. The caged ball type is similar to a CV joint in a front wheel drive car or a Birfield from a Samuri or Toyota front axle. The caged ball type CV joint is notoriously weak and is it fortunate that these drive shafts can be found in only a few four wheel vehicles including some Bronco II's and a few early XJ Cherokees. Most who find caged ball type CV drive shafts on their vehicles quickly upgrade to a standard double cardan type CV drive shaft.

Tube It Out! Building a tube rockbuggy

There are many ways that tubing out portions of your four wheeler can improve it's off road performance. It can improve departure and approach angles, allow more engine cooling, protect the engine and radiator in case of roll over, allow larger tires with no lift, and improve visibility. Maybe the best reason is it just looks cool.

Don't let this happen to your springs. Springs can deflect to take this shape under load, when the pinion has rotated up in reaction to the torque applied to the tires

Axle wrap is a problem that plagues leaf sprung vehicles with soft springs, particularly those that are set up SOA (Spring Over Axle). Axle wrap is something different than wheel hop. Wheel hop is when an axle on your 4x4 rapidly hops up and down. Axle wrap is unwanted suspension movement that allows the pinion angle to change. Wheel hop is annoying and could cause drivetrain breakage, but usually it's not the actual hopping that breaks parts, it's the axle wrap that results from the hop that causes drivelines to bind and breaks yokes, drive shafts, and sometimes even pinions.

"It's just a steel tube with a u-joint at each end that transfers torque from the output of the transfer case to the axle. Nothin' special, right?" Well... yes, but that is an over-simplified answer.

There are many subtle things about a drive shaft and the conditions it operates in that will greatly affect how well the drive shaft performs. These subtle variables may have a profound impact upon the life of the drive shaft components, the amount of vibration the drive shaft produces, and whether or not the drive shaft is even capable of meeting your vehicle's specific requirements.

In this article we'll explain some of these subtle but extremely important variables, teach you about the different types of drive shafts that exist, and help you understand how to adjust the operating angles to ideal for the type of drive shaft that you have.

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