I thought the newer E70s have "in wheel" real time pressure monitoring,
but I could be mistaken, as I don't have the E70...
RealTime is the deal, but the "indirect method" was the "granny/soccerMom" compromise, and
the indirect method is
still used in many models of many brands. The pressure loss trigger value,
while mandated on the low/less acute side, is also variable, if within the specs on pressure loss, per
make and model; some mfg's that use the indirect method use a "quicker/sooner" pressure loss than others.
-Boring azz NHSTA pdf:
http://www.tireindustry.org/pdf/TPMS_FinalRule_v3.pdf
-In a nutshell from the tire lobby:
http://www.tireindustry.org/governme...s_comments.asp
Real Time TPMS has been std on Vettes for a long time...the runflat tire deal made it a req'd system.
My50Cts is up...
GL,mD