With bike locks, you're not looking for tensile strength, you need to resist shearing & shock loads. Carbon fiber, for example, may be considered to be almost

With bike locks, you're not looking for tensile strength, you need to resist shearing & shock loads. Carbon fiber, for example, may be considered to be almost as strong as steel, but it breaks pretty easily when subjected to shear and shock forces, i.e. a bolt cutter. Quickly skimming the article, graphene is only twice as strong as steel in this regard. Although this is still great, you have to be careful.