Editing Disc brake (section)

===Cracking===
Cracking is limited mostly to drilled discs, which may develop small cracks around the edges of holes drilled near the edge of the disc due to the disc's uneven rate of expansion in severe-duty environments. Manufacturers that use drilled discs as [[Original Equipment Manufacturer|OEM]] typically do so for two reasons: appearance, if they determine that the average owner of the vehicle model will prefer the look while not overly stressing the hardware; or as a function of reducing the [[unsprung weight]] of the brake assembly, with the engineering assumption that enough brake disc mass remains to absorb racing temperatures and stresses. A brake disc is a [[heat sink]], but the loss of heat sink mass may be balanced by increased surface area to radiate away heat. Small hairline cracks may appear in any cross-drilled metal disc as a normal wear mechanism, but in severe cases, the disc will fail catastrophically. No repair is possible for the cracks, and if the cracking becomes severe, the disc must be replaced. These cracks occur due to the phenomenon of low cycle fatigue as a result of repeated hard braking.<ref name="2013_rashid_discbrakes">{{cite journal|last1=Rashid|first1=Asim |last2=Strömberg |date=17 October 2015 |title=Sequential simulation of thermal stresses in disc brakes for repeated braking |url= http://hj.diva-portal.org/smash/get/diva2:618167/FULLTEXT01 |journal=Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology |volume=227 |issue=8 |pages=919{{ndash}}929 |doi=10.1177/1350650113481701 |s2cid=3468646 |access-date=18 February 2024}}</ref>