 Less vibration, better performance and feel for high-performance disc assembly |
AP Racing has announced a new kind of brake disc that it said is designed to outperform and outlast conventional high performance discs currently used by track day vehicles and fast road cars.
The new Strap Drive discs almost eliminate the vibration, warping and noise that degrades performance and increases rates of wear on one-piece discs and ‘floating’ discs during sustained, intensive use, said AP.
The disc (for which AP has made patent applications) features flexible stainless steel straps that attach the disc to a separate aluminium mounting bell. According to AP, these flexible couplings allow the disc a limited degree of controlled movement, so that it always aligns true in the centre of the caliper, even under extreme use and regardless of changing operating temperatures.
By using the strap couplings to isolate the disc from the mounting bell, the Strap Drive concept also avoids the warping and distortion that often affects one-piece discs. This occurs as a direct result of the temperature differential between the working surface of the disc – which expands and contracts as temperatures rise and fall – and the much cooler central mounting bell. By avoiding these physical distortions, the Strap Drive concept limits the potential for any drop-off in brake performance and also ensures consistency of pedal ‘feel’.
AP reckoned that its Strap Drive offers "a compelling alternative" to standard floating disc brakes, where the disc is able to move independently of the mounting bell along small bolted attachments, called ‘bobbins’. This type of movement can often make floating discs noisy in operation, as well as promoting wear and vibration. The bobbin slots can eventually fill up with road / brake debris, causing them to seize. AP Racing’s ‘strap’ couplings suffer from none of these drawbacks, according to the company.
AP said that, with no moving parts, Strap Drive discs have proved far more durable than traditional floating discs during its testing programme. Strap Drive discs are also expected to outlast one-piece discs, which will need to be changed at an earlier stage due to the onset of warping or distortion.
The discs have been developed to work with a vehicle’s conventional calipers, said AP, and replacement discs are available separate from the mounting bell for cost-effective servicing.
AP Racing is currently in the advanced stages of talks with a number of vehicle manufacturers about supplying Strap Drive discs as original equipment items. At launch, Strap Drive discs will be available as aftermarket installations for the Mitsubishi Lancer Evo series and the Subaru Impreza – both of which often experience brake disc durability problems under track conditions. AP Racing plans to develop Strap Drive kits for a wide range of other performance vehicles, particularly those equipped with large discs.
Prices, inclusive of VAT, are as follows:
Mitsubishi Lancer Evo VI, VII and VIII:
- Disc, Bell and Pad kit (CP3781T23P) – £668.00
- Pad set (CP3915-39-DS2500) – £158.00
Subaru Impreza (2000 to 2005)
- Disc, Bell and Pad kit (CP5175T41CG8) – £668.00
- Pad set (CP3915-39-DS2500) – £158.00
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