High Pinion Axle
A high pinion axle housing design has the pinion shaft entering the housing above the axle tube centerline. The ring and pinion gear teeth are cut in the opposite direction to allow this relocation of the pinion shaft entry point. Sometimes this axle is mistakenly called a “reverse rotation” axle but this is not correct. The ring and pinion still rotate in the same direction but the tooth pattern is reverse cut allowing the driving force to be carried on the stronger side of the ring gear teeth when a high pinion axle is used in the front of a 4 wheel drive vehicle. When used in the rear of a 4 wheel drive vehicle some strength is lost since the driving force is applied to the weaker side of the ring gear teeth. For this reason many people choose to install a Heavy Duty 60 series axle such as the Tera CRD 60 in the rear of a light weight vehicle.
IFS
Independent Front Suspension refers to a vehicle suspension design where the front knuckles mount to the frame through ball joints and some type of upper and lower A-arms. This design allows either side to travel up and down independent of the opposite side. IFS has been used for many years in cars, and is now common in 4 wheel drive vehicles.
Knuckle
The knuckle connects the wheel assembly to the axle housing inner knuckle or C-Yoke through 2 pivot points and creates a mounting point for axle components such as tie rods, unibearings or hubs, brakes, etc.
LCA
The lower control arm is a suspension component that connects the axle to the frame of the vehicle. These can be lengthened and shortened to fine tune alignment and pinion angle.
LCG
Low Center of Gravity.
Leaf Spring
The most traditional suspension design until the mid 1990’s. Leaf springs utilize an arched steel strap that is heat treated and combined into a multiple leaf pack to give the vehicle its intended height. Leaf springs are very stable and offer a relatively stiff ride.
Long Arm
Lower long arms increase the arm length by almost double in most cases, and will provide the vehicle with increased on road drivability and off road articulation.
LWB
Long Wheel Base vehicles generally have over 100” of wheelbase. This includes the Cherokee, and Grand Cherokee.
Nodular Iron
Nodular Iron (Ductile) is a cast iron that has been treated while molten with an element such as magnesium or cerium to induce the formation of free graphite as nodules, which imparts a measurable degree of ductility to the cast metal. Nodular iron is commonly used in casting automotive differential housings.
OEM
Original Equipment Manufacturer is the supplier of equipment that came stock on a vehicle or was specified by the factory for production vehicles.
Open Differential
An open differential allows different wheel speeds for smooth turns on high traction surfaces. This is great for driving on the road, but in low traction situations the open differential allows all vehicle torque to be transmitted to the wheel with the least amount of traction.
Pitman Arm
The pitman arm connects the steering box to the drag link. On lifted Jeeps a drop pitman arm is usually needed to restore proper steering linkage geometry.
Ring & Pinion
The ring and pinion transfer power from the driveshaft to the axle shafts. Ring and pinions come in various ratios to allow the wheels to turn at a different rate than the transfer case. Ring and pinions consist of a smaller gear (pinion) which turns a larger circular gear (ring).
Revolver Shackle
The Revolver Shackle is a unique shackle that is hinged to allow additional articulation and down travel. It also will help to reduce leaf spring stress when under articulation.
Rock Crawler
A purpose built 4x4 vehicle to crawl over rocks and boulders.
RTI
RTI or ramp travel index is a measurement of a vehicle’s suspension flex or articulation. This can help to show areas that need attention before the vehicle is taken off-road, or to measure for new components such as shocks or brake lines.