In today's market, you can choose between three main caliper production methods for your brake kit. You should always make sure you know which of the three methods was used to produce your new calipers and what their limitations can be.
What are these methods?
So what’s better, billet or forged?
Most people will look at a forged caliper and think it must be the strongest. This is not always true, it depends entirely on the materials used. Typically, a forged caliper will use a lower quality alloy than a billeted caliper.
To forge a caliper, it must be forced into shape using a press. This compression gives a forging its strength. A billet caliper is machined from a solid block, with no deformation of the material. This means the alloy can be of a much higher, stronger quality. However, forged calipers when heat treated hold a better grain structure, which does make a forging the stronger of the pair.
So forged is stronger after all?
Unfortunately, forging is much like casting, making its tolerances inaccurate. For an item such as a brake caliper, tolerances are vital. Billeted caliper are produced entirely on CNC machines, which allows their accuracy to be fine tuned to within thousandths of a millimeter. To get a forging this accurate, it must also be CNC machined.
So what’s the problem?
Once a forging is cast and heat treated, its stress and fatigue strength are set. By machining the forging, you unbalance the structure, increasing the internal stress and dramatically decreasing fatigue strength.
Why doesn’t this affect billet?
When a billet is produced, there is no added compression in its structure to draw its strength from, there is no balance to upset by machining. The fatigue strength of billet can even be improved by vibratory finishing or sand blasting the final product. This removes any burs from machining, giving clean lines and that all important rigidity a casting or forging just cannot compete with.
So does the extra machining and finishing make billet expensive?
Due to the large amount of wasted material produced from a billet, it is the most expensive method of the three for a single item. However, a benefit of billeted calipers is the ability to mass produce them. CNC machines can be fed huge lengths of metal, producing dozens of identical parts with amazing accuracy which require very little human finishing. This makes billet components perfect every time, cuts lead times and most importantly, keeps money in your pocket!