EXPERT
for on-road grime and water . The shape is claimed to be better for disc thermal expansion / contraction and better heat dissipation .
How are discs secured to carriers ? There are various methods : most use a rivet system , and the number used ( six minimum usually ) depends on how much unsprung weight is trying to be saved . Lots of manufacturers use a circular button / hole system , but others use a square-sided rivet / hole – the different designs are all trying to reduce warping and / or vibration . Circlips can also be used . A large stainless steel retaining clip connects the outer rotor to the inner carrier , with recessed grooves for the clip to fit into , ideal for quick changing ( especially in a racing setting ).
What about performance ? On road , using stainless discs with sintered pads provides high initial bite and the temperatures reached normally aren ’ t high enough to cause brake fade . For track use , the stainless steel / sintered pads combo can lead to brake fade due to the inherent heat build-up through using metal on metal contact ; so again , a highgrade stainless steel disc should be used , and organic pads can help reduce brake fade .
Can discs be repaired ? It ’ s not advised generally and is really only possible on slightly warped / bent discs . It ’ s also a good idea to get them looked at first by an expert to ascertain if they can safely be repaired . Heating can cause metal fatigue , so the safest technique is to use hydraulic presses and specialist measuring tools to obtain the required disc trueness . Second-hand discs are not normally the best idea either as you don ’ t know what they ’ ve been through . Don ’ t buy without seeing / feeling them first as you need to check for cracks , ridges and pitting on the disc face . Rub fingers across the disc - if imperfections feel deep or there ’ s an obvious thickness difference between the disc face / outer lip , then it ’ s time to get the Micrometer out to accurately measure for minimum operational thickness .
72 KIWI RIDER