Valve Nuts? - A common question with Presta valves is whether or not it's important to install the valve nuts (there are two types: nuts and rings with knurled edges). Not all Presta valves are threaded from top to bottom. But, if yours are threaded, there's a good chance that there are valve nuts on them. These can make it easier to inflate the tire because they hold the valve proud of the rim making it easier to get the pump head on them. Be sure not to tighten them too much, however, or they'll be difficult to remove by hand when you have to fix a flat on the road or trail. Over tightening the nut can also put pressure on the valve/tube junction where it passes through the rim, possibly causing a flat. Also, when fixing a flat, install the valve nut after the tire and tube have been installed (just before inflating).