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.
Gas. Some cyclists prefer to use gas cylinders to pump up tires. This type of pump is the smallest of all the pumps and will fit into any small pack on the bike. The gas cylinder fits inside a small housing. The housing attaches to the bike's valve and then a small trigger is used to discharge the gas into the tube.