What is the purpose of the bridge washer in the tire valves??
Is it to lock the stem to the rim.??
I could be wrong, but I think it is to put pressure on the joint where the rubber meets the metal. The spring will hold the metal firmly in place in the rim with the rubber sandwiched between the bridge washer and the flange on the stem inside the tube.
Norm
Lorenzo,
Dan Treace has your answer at
http://www.mtfca.com/discus/messages/257047/261702.html?1327192622
Dave
Thanks Dave, a lot of useful info...[That special washer with tangs won't rotate, and keeps the metal stem from twisting from the tube.]