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Basic Alignment and Geometry
What is wheel alignment?
Alignment (also known as front-end geometry) refers to the position of the front wheels relative to each other, the ground, and to the vehicle. Correct alignment must be maintained to provide safe, accurate steering, vehicle stability, maximum performance, and minimum tire wear. The factors that determine wheel alignment are mutually dependent. Therefore, when one factor is adjusted, the others must be adjusted to compensate, as well. Here we'll attempt to shed a bit of light on the subject relative to your performance vehicle.
There are basically four critical factors that make up correct steering geometry; Caster, camber, toe, and inclination. All, as stated above, are co-dependant and the correct orientation of each meld to provide optimum control and drivability in any vehicle, performance oriented or not.
Caster is the orientation of a line, drawn through the center of the upper and lower ball joints and viewed from the side, can be tilted forward or backward. Positive caster means that the top of the upper ball joint is tilted toward the rear of the vehicle, and negative caster means that it is tilted toward the front. A vehicle with a slightly positive caster orientation will have its lower ball joint pivot slightly ahead of the tire's center. This will assist the directional stability of the vehicle by causing a drag at the bottom center of the wheel when it turns, thereby resisting the turn and holding the wheel steady in whichever direction the vehicle is pointed. A vehicle with too much (positive) caster will be hard to steer and shimmy at low speeds. A vehicle with insufficient (negative) caster may tend to be unstable at high speeds and may respond erratically when the brakes are applied.
Camber angle is the number of degrees that the wheel itself is tilted from a vertical line, when viewed from the front. Positive camber means that the top of the wheel is slanted away from the vehicle, while negative camber means that it is tilted toward the vehicle. Normally a vehicle will have a slight positive camber when unloaded. Then, when the vehicle is loaded and rolling down the road, the wheels will just about be vertical. If you started with no camber at all, then loading the vehicle would produce a negative camber. Excessive camber (either positive or negative) will produce rapid tire wear, since one side of the tire will be more heavily loaded than the other side.
Toe-in is the difference (in fractions of inches) between the front and the rear of the front tires. On a vehicle with toe-in, the distance between the front wheels is less at the front than at the rear. Toe-in is normally only a few fractions of an inch, and is necessary to ensure parallel rolling of the front wheels and to prevent excessive tire wear. As the vehicle is driven at increasingly faster speeds, the steering linkage has a tendency to expand slightly, thereby allowing the front wheels to turn out and away from each other. Therefore, initially setting the front wheels so that they are pointing slightly inward (toe-in) allows them to turn straight ahead when the vehicle is under acceleration.
Steering axis inclination is the number of degrees that a line drawn through the upper and lower ball joints (or strut and lower ball joint) and viewed from the front is tilted to the left or the right. This, in combination with caster, is responsible for the directional stability and self-centering of the steering. As the steering knuckle swings back and forth from lock to lock, the spindle generates an arc, causing the vehicle to be raised when it is turned from the straight-ahead position. The reason the body of the vehicle must rise is straightforward: since the wheel is in contact with the ground, it cannot move down. However, when it is swung away from the straight-ahead position, it must move either up or down (due to the arc generated by the steering knuckle). Not being able to move down, it must move up. Then, the weight of the vehicle acts against this lift, and attempts to return the spindle to the straight-ahead position when the steering wheel is released.Why is proper wheel alignment so important?
In the long run, it will prolong the life of your car, and save you money, and just as importantly to us, increases and optimizes handling and street performance. As a bonus, especially these days, correct wheel alignment results in better fuel mileage, and it actually extends tire life on rear tires as well as front tires. In fact, the most common cause of unusual tire wear is improper alignment.
The Ackermann principal
There is another geometric factor that plays a part in automotive handling called Ackermann. It's primarily relegated to slow-speed maneuvering and early, more rudimentary steering systems but it is worth mentioning here.Ackermann is a geometric arrangement of linkages in the steering of a car or other vehicle designed to solve the problem of wheels on the inside and outside of a turn needing to trace out circles of different radii. In other words, when a vehicle is steered, it follows a path that's part of the circumference of its turning circle, which will have a center point somewhere along a line extending from the axis of the fixed rear axle. The steered wheels must be angled so that they are both at 90-degrees to a line drawn from the circle center through the center of the wheel. Since the wheel on the outside of the turn will trace a larger circle than the wheel on the inside, the wheels need to be set at different angles.
The Ackermann steering geometry arranges this automatically by moving the steering pivot points inward so as to lie on a line drawn between the steering kingpins and the centre of the rear axle. The steering pivot points are joined by the tie rod, or a rack and pinion, this arrangement ensures that at any angle of steering, the centre point of all of the circles traced by all wheels will lie at a common point.
Borgeson / Mullins offers steering boxes for your Chevy. With a complete line of both manual and power boxes, let us help you with your restoration project or up-grade. For the tri-5 Chevy we offer a manual replacement with either the long or short input shaft option. The long input shaft is needed if you are going to use the stock column. We offer the short input shaft to make the replacement of your column that much easier. These boxes are offered with the stock 22:1 ratio or the "quick" ratio 16:1. We also offer manual to power conversions for these vehicles. They are offered with either bolt in or weld in brackets. Along with the Tri-five Chevy's, we offer both manual replacements and power up-grades for the 58-64 Chevy. We offer either long or short input shafts for the 63-67 Chevy II and the 16:1 ratio manual box for the 63-82 Corvette.
With all the steering box replacements and up-grades we offer for your Chevy, we also offer all the accessories. From "dress up" side covers to drag link adapters to pitman arms, mounting brackets, rag joints, power steering pumps, power steering hoses and floor mounts we have your entire Chevrolet steering needs covered. For any technical or ordering information, please call 860-482-8283. Borgeson Universal Company / Mullins Steering Gears, 91 Technology Park Drive, Torrington, CT 06790, www.borgeson.com
CPP 600 Series Power Steering Box
CPP, a leading producer of power re-circulating-ball steering gears, has combined experience with cutting-edge technology to manufacture a new 600 series of steering gears that provide directional control of the vehicle. The 70mm piston provides better road feedback and a more stable feel to the driver.
Designed around a modern Saginaw steering box, Classic Performance's power re-circulating-ball gears feature low friction and quick response. An open-centered, rotary-type valve provides smooth and quiet operation throughout the steering range--while retaining excellent road feel. The integral rack piston converts hydraulic pressure to a rotation force that moves the steering linkage left or right. The steering system and hydraulic fluid also acts as a cushion to help absorb road shocks. All components are new (not rebuilt), and 100% tested in the factory. Available now for immediate shipping.SPECIFICATIONS:
Steering ratio: 14:1
Input shaft is 3/4"-30 spline (the same as the 605 box)
Sector shaft is 1" 36-4 tapered spline, the same as the original 1955-57 pitman shaft
Pressure fitting is 7/16 tube (11/16-18 inv. fl.)
Return fitting is 3/8 tube (5/8-18 inv. fl.)
Classic Performance Products, Inc. has been providing the classic Chevy and Ford truck, as well as Chevy passenger car market with top quality steering, brake and suspension components for the last two decades. Call and order a catalog today, featuring our complete line of parts and accessories. Classic Performance Products, 175 E. Freedom Ave., Dept. SC, Anaheim, CA 92801, 714-522-2000, www.classicperform.com.
Power Steering Pumps
The engineering staff at Detroit Speed and Engineering has taken the power steering pump to a new level of performance. All Detroit Speed power steering pumps are completely new, not remanufactured assuring you of a long life with superior operation. DSE's pumps are engineered to deliver a constant flow under different operating pressures and are compatible with any power steering gear or rack and pinion. The transverse bearing compact pumps(TC pumps) are less sensitive to radial belt loading than other types of pumps.
These TC pumps offer high efficiency and quiet operation delivering a flow of 3.0-3.4 gallons per minute at 1500 rpm and with a relief pressure of 1250-1450 psi. All pumps are available with a Mustang II flow control valve that will restrict the flow to approximately 2 gallons per minute while retaining the appropriate pressure in the system.
Pumps are offered in a variety of styles to fit your particular application. Available designs are cast iron housing with integral reservoir, light weight aluminum housing with integral reservoir, polished aluminum housing with integral reservoir and a chromed cast iron version. Pumps are also available without the integral reservoir if you need this style.Detroit Speed & Engineering, 185 McKenzie Rd., Dept. SC, Mooresville, NC 28115, 704-662-3272, www.detroitspeed.com.
New Power Rack Conversion for Classic Camaros!
Berea, Ohio -- Flaming River Industries announces the availability of the power rack & pinion conversion kits for the classic 1967 to 1969 Camaros.
As with the popular Flaming River manual kits, the power kits utilize a similar bolt-in cradle to mount the rack to the existing frame mounting holes. The cradle design retains the stock frame cross member to assure the frame's integrity is not compromised. There is no drilling, cutting grinding or welding needed for installation.
The jig-welded kit includes all mounting hardware (universal joints, steering shaft, a FR1570 speed sensitive pump, FR1614 billet remote reservoir and fasteners). Kits are available with or without the Flaming River polished or paintable stainless steel steering column. The cradle kit requires only simple hand tools for installation.
The Power Rack conversions are available for small block engines with stock cast iron or aftermarket header exhaust systems.
A unique feature of the Flaming River rack & pinion kits is there is no change to the stock chassis and suspension design. The cradle installation will add strength to the frame. This system uses the 1969 Camaro original equipment outer tie-rod ends.All required installation hardware is included with each kit. All fasteners meet or exceed the OEM specifications. The power and manual rack & pinions will not interchange. Plumbing is not included. FLAMING RIVER INDUSTRIES, INC. 800 Poertner Drive, Dept. SC, Berea, OH 44017, 440-826-4488, www.flaming-river.com.
55-57 Rack and Pinion Kit
Unisteer Performance(TM) offers the ultimate steering upgrade for Tri-5 Chevys, with its rack and pinion kits that greatly improve handling, responsiveness, and steering effort. Each kit includes a custom rack and pinion (power or manual) that has been painstakingly engineered to duplicate the stock steering linkage pivot points, thus avoiding bump steer problems found in similar kits. Installation is a breeze; do to the bolt in mounting brackets. No cutting, drilling or welding is needed; this kit simply uses existing holes in the frame and all the hardware is included. New steering arms and tie rod ends are included and are compatible with all after market spindles that accept factory steering arms. The manual unit is ideal for drag racers, reducing weight and improving responsiveness. If corner carving is what you have in mind, the power unit with its 2.65 total turns is ideal. The standard finish is black powder coating, and a show quality chrome finish is also available. Additional parts such as steering shafts, pumps and lines are available and sold separately. A low flow pump is recommended for the most desirable road feel. Maval Manufacturing, 1555 Enterprise Pkwy., Dept. SC, Twinsburg, OH 44087, 800-338-9080, www.mavalgear.com.