Something new we are offering...carbon fiber spikes. Very lightweight, noncorrosive, and low profile they make a good backup item.
Tip comes with a basic profile thats been chamfered, you can very easily reshape it by rubbing it on a coarse grit sharpening stone, or sandpaper on a flat surface...if you prefer it sharper, blunter, more acute, more obtuse, etc. Carbon fiber is very strong but not very abrasion resistant so it sharpens much quicker than steel.
I actually put off doing these for years because I wasn't sure how strong they would be. Well after finally getting around to making some test pieces and literally hammering them through 1" thick wood with a deadblow hammer...I'm impressed. A small portion of tip does get rounded off doing this, but there was zero structural damage after hammering it through dozens of times. The dulled tip can easily be sharpened on a regular sheet of sandpaper(400 grit works well) in a few seconds to minute depending on experience. These are intended for lighter tasks, (like unknotting rope....use a nail if you want to hammer through wood), but they can definitely hold up to some abuse.
Being very lightweight, these are not intended as a throwing spike...its like trying to throw a straw with force.
Specs:
Ground from solid nonwoven carbon fiber
10mm diameter at the widest (just over 3/8"..which is 9.5mm)
6" length (length will vary slightly due to being handmade)
Handle is texture to aid grip