[ronin]

Installed the metzler 240 recently, have over 1000 miles on the tire. Left the bike alone for 5ish days went back this afternoon and the rear tire has 3 psi. I can't find any punctures or breaks....any thoughts on what could have gone wrong??

 

[UrbanRage]

I would check the valve core.

 

[christopher]

You could also have a seating problem as in a defect in the rim of the tire. But I would check or change the valve stem plug first.

 

[MY LIFE]

Valve stem. Soapy water on the end of the stem should prove or disprove, but for such a small cost I would replace it anyway.