For people with hearing loss, the sound signals from the inner ear to the brain will be weaker than normal, and it's possible that the brain amplifies these signals too much to compensate, resulting in hypersensitivity. However, this doesn't explain the cause in those with hyperacusis and no hearing loss.
Bicycle Valve Stem Types. There are three types of bicycle valve stems in use: Schrader, Presta and Woods/Dunlop. The Woods or Dunlop valve stem style is much more rare than the other two. Any wheel rim that fits a Schrader valve can also fit a Woods or Presta valve.
There are two main bottom bracket types. More common on older bikes is the cup and cone style shown to the left. On modern bikes the most common is the sealed cartridge bearing shown to the right. The easiest way to identify which you have is to look at the bottom bracket on the non-drive side of the bike.