[Land-speed] Tire Valves

Kirkwood saltfever at comcast.net
Sat Jan 23 01:34:55 MST 2010


Thanks for all the comments so far. JT's comment got me thinking so I ran a
few numbers. My rims will be steel and either about .160'' or .190''
thickness. The vendor has mentioned both thicknesses! The 1/8 NPT is 27 TPI
making a thread about .037'' wide. So if I have the .160'' thick rim it will
engage about 4 threads. The nominal diameter of the thread is .405'' and  at
70 psi tire pressure there would be a blow-out force of about 9 lb. I doubt
that pressure is as big an issue as centrifugal force. But it is a force
applied in the correct direction! Centrifugal force is forcing the valve
into the rim and not out. If the rims are thicker then obviously more
threads would be engaged. As a first look, forces appear to be within
reason. But more about Dave's comment next  . . .


More information about the Land-speed mailing list