_________________________________________________________________________________ Cambered Rear End Tech Info A cambered rear end consists of a one piece rear end which has been modified to let the tires rotate in a plane that is not perpendicular to the axle's rotation. Getting your race car's tires to lay flat on the track is what rear camber is all about. Tire stagger complicates your ability to achieve maximum tire contact. This leads you to several problems. Tire wear is greater on most heavily loaded part of the tire. Rear tire temperatures are greater on the heavily loaded part of the tire leading to uneven tire temperatures across the tire width. Therefore your race car will not get around the corner as fast as it could because you are not efficiently using all the tire. When the correct amount of camber is set, the tire temperature will be even across the tire. This means that more tire is being used and your race car goes faster. Until recently it has been impossible to camber rear wheels unless you ran an independent rear suspension due to the bind created between the axle spline and drive flange. When you move the outside spline out of line with the inside spline you create a natural bind causing the axle to bend a little bit every time the wheel makes a complete revolution. Related parts breakage will also occur, bearings wear out sooner, seals leak, and pressure in the drive plate spline is up to the edge of failure causing excessive wear and teeth breakage. We have developed offset machined snouts for both Super Speedway and Short Track Rears. These offset snouts allow you to run up to 2 degrees of rear wheel camber and keep both axle splines operating on the same plane therefore eliminating bind in axle rotation. Of course you must do one of the following; either run a Quarter Master constant velocity 3 piece drive plate or a crowned axle and a specially heat treated drive plate to help handle high pressure in the drive plate spline. Remember also that the tire stagger gives you natural camber. Narrow rear ends with large amounts of stagger have lots of natural camber. Conversely, wider rear ends with small amounts of stagger will have less natural camber. Equal tire temperatures across the rear tires indicate proper camber. To calculate how much natural camber your rear end has use this formula: ST /
6.283
x CD x .0175 = CAMBER Example: Say you are running 3" of tire stagger and your rear end has 50" between the center of the drive flange splines. Take 3" and divide that by 6.283 which equals .477. Multiply .477 by 50" which equals 23.784. Now multiply that by .0175 which equals .41622. The answer: 42 degrees rounded. Almost all race cars will work better with some rear wheel camber. Once you know how much natural camber your tire stagger is putting in your rear it will easy to determine how much camber you need to add to even up your rear tire temperatures. Finally, something else to be aware of when installing cambered rear in your car. If your sanctioning body has maximum track width restrictions and you are near that limit, camber may tip the tire out enough to put you over the tread width limit. Here is a simple formula to figure how much your track width will change with a given camber angle. R x C .0175 = Track
Width Increase Per Tire If your tire has 28" diameter then the radius is 14" and you install 1-1/2 degrees of camber 14" x 1.50 degrees x .0175 = .37. Wider on one side of the rear. What camber angle is right for your car? We don't know. What we can say is that tire temperature is an accurate way to determine if camber is correct. Remember if you decide to camber your rear end you cannot just bend the tube and go to the race track. You must insure that the hub / wheel assembly is concentric to the axle, and the axle is not in any kind of bind. ______________________________
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