The 2-piece disc assemblies used in our (Stage-2) X-Line 4x4 big brake kits are cast from a proprietary high-carbon cast iron alloy that provides excellent durability and stability under the high thermal loads experienced under fast-street or off-road driving. The discs feature 72 x curved, directional cooling vanes. The design significantly increases cooling vane surface area and air-flow when compared to factory / OEM disc designs, resulting in vastly improved cooling.
The slot pattern chosen for our X-Line 4x4 discs is our well-proven “AT” slot pattern that provides a good balance between functional aspects such as efficient removal of sand, mud and water (when driving in the rain or after river crossings) and practical aspects such as low levels of noise, vibration and harshness (NVH) under braking. The slot pattern also provides good bite and release characteristics.
Every single Powerbrake 2-piece disc assembly is measured for run-out and disc thickness variation (DTV) using Swiss measuring equipment. When it comes to QC, there is no batch or statistical quality checking of Powerbrake discs. Every single disc is measured. Our machining tolerances are up to three times tighter than the industry norm.
All our X-Line 4x4 disc rings are coated with a proprietary black surface coating. The discs are chemically de-greased before the application of this coating to ensure that no machining fluids or other contaminants that can be absorbed the brake pads and negatively affect brake performance are present on our discs at all. The coating is able to withstand extremely high temperatures and is flexible enough to expand and contract without flaking or peeling off of the disc surface during the constant thermal expansion and contraction cycles experienced by the brake disc.
Our X-Line 4x4 disc disc assemblies require no cleaning or preparation using solvents at all. Simply ensure that the car's hub is clean and fit the discs as they come out of the box. The black coating will be removed by the brake pads in the pad track areas within the first 4-5 brake applications. The un-swept areas of the disc will remain coated. While our disc coating was primarily designed to ensure that there was zero presence of oils and contaminants on our disc surfaces at the time of fitting (and was not in fact designed to provide corrosion protection), practical experience has shown that the non-swept areas of our coated X-Line 4x4 discs will in fact resist the common formation of unsightly surface rust on the non-swept areas of the discs quite well (depending on environmental conditions in your area). This results in a far more visually appealing assembly visible through the car's wheels.
Unique to Powerbrake, all X-Line 4x4 discs feature our MTR system that provide a permanent record of the peak operating temperature reached by the discs. This information is extremely valuable when selecting correct pad compounds for your application. The thermal-paint tabs are applied to the outside diameter of all X-Line 4x4 discs (on both the inboard and outboard disc plates).
Each single-change paint colour (4-levels: Blue, Green, Orange and Pink) changes to white when a specific temperature is reached, hereby providing a record of the peak operating temperature of the disc. We also add a multi-change paint that can be used with a provided colour gradient chart to further refine the results to a more specific temperature. The simple information required to interpret the results recorded by the MTR system on our X-Line 4x4 discs is provided in the instruction manual that accompanies every X-Line 4x4 big brake kit.
The light-weight disc hats used in our X-Line 4x4 disc assemblies are machined from a solid billet of high grade aluminium alloy. Again, machining brake components from solid billet is expensive but it results in an extremely strong finished part. All hat designs undergo FEA strength and thermal analysis to confirm strength and rigidity under load. The hats are then finished with a dark grey, type-3 hard anodise for maximum durability and service life. Logos and other information are then laser etched on the outboard face of the hats.
At Powerbrake we have many years of R&D invested in disc float systems. We have developed advanced float systems for our full race brake systems for applications ranging from circuit racing to FIA off-road and Dakar Rally. For our X-Line 4x4 big brake kits, we decided to use semi-float system that has been very well proven within our big brake kit range over many years of use.
The semi-float system allows the disc friction ring to expand and contract radially without any restriction as it heats and cools. This significantly reduces stresses within both the disc friction ring and the disc hat and reduces the chance of disc distortion and cracking, while ensuring a very consistent brake pedal feel.
The design brief for our X-Line 4x4 big brake kits was to provide race-proven technology to the 4x4 and off-road markets. As a result, attention was given to ensuring low of NVH (noise, vibration, harshness) under street driving conditions. Our semi-float system runs particularly quiet during day to day street driving.
At Powerbrake, we believe strongly in the benefits of machining our multi-piston calipers from solid billet. All of our championship winning X-Line and R-Line race calipers are machined from high-grade aerospace aluminum billets, and we’ve chosen to manufacture the X-Line 4x4 range from the same material. Machining from billet is admittedly an expensive way to manufacture calipers but it results in a finished product that exhibits exceptional levels of strength and rigidity.
How do we bring our billet X-Line 4x4 calipers to the market at such competitive prices? Through significant investment in state-of-the-art 5-axis CNC production equipment that allows us to machine the calipers with maximum efficiency. The fact that we machine all of our calipers from billet, matched to the FEA enhanced caliper designs themselves, results in calipers with an impressive rigidity to overall size ratio. The slim profile of the calipers reduces un-sprung weight and aids with wheel clearance.