I purchased an excellent floor-ceiling bike rack from these guys to store a couple of road bikes. The problem was that the default hooks were suited to aluminium frames with a circular profile, rather than the larger profile of modern carbon fibre frames.

I have tested the hook with > 20Kg load for several days, with no signs of stress damage or deformation. Two of these are currently supporting my <10Kg bike with no problems,

The side notch takes two M6 nuts which provide a firm hold on the factory bolt.