The first decision (and maybe the most important) is what material the bolts should be manufactured from. If you are looking for anodised bolts
your choices are basically limited to aluminium
and titanium. This is due to the fact that not all metals can be anodised.
If the bolt is to be used in a high stress application such as disk bolts or suspension mounts, Titanium should be used as it has a higher tensile strength. If you are fastening dials, faring
or the petrol cap for example, aluminium bolts can be used.
The other important consideration when choosing the type of anodised bolts is the colours that are available in the different materials. Generally speaking aluminium bolts will have a larger range of colours than the Titanium counterparts. This should however not interfere with your safety considerations, if the required colour is not available in titanium for a high stress application, rather opt for a silver or alternative available colour.
Some people may wish to avoid bolts that are anodised a colour and opt for the normal silver colour. This is especially true when doing original restorations and vintage reproductions. Even in this case, the plain silver anodised bolts will have an advantage over conventional steel bolts, and that is they do not rust.
Rust is not an issue using bolts
that are anodised because of the specialised chemical process they are put through. With out getting into the process of anodising
too much, the parts are dipped into a chemical solution with electricity flowing through the solution and parts. This process also chemically hardens and seals the metal, which is why it will not show signs of rust or tarnishing after being anodised.