chris.hanle

I am replacing my tires and have what I think are original tpms (09). My durametric reading on life of the tpms batteries are 60 months. I know that my next set of tires will not last that long. But my question can I trust the accuracy of the durametric on this? I will say that two were listed at 62 months and two 60. Anyone run their durametic and the estimated time was way off on the actual life of tpms?

Minok

I guess it depends on what Durametric is reporting. My understanding is the batteries deliver no power when the car is stationary, and power the sensor when its rolling. So I'd expect the batteries to last longer if the car is driven less, and last less long if its driven more. If the tool is taking mileage over the past year of time as an average rate and using that to prognosticate how long they should last, I would think its relatively accurate if you stick to that usage. But I don't know how that 60 mos estimate is derived. The sensors themselves don't compute it, I would expect. Maybe its derived from a table on battery voltages.

chris.hanle

Makes sense, but also a little less reasuring. Anyone get a diffent result than durametric reported?

stronbl

You ask a very interesting question - don't know a definitive answer but ... from my experience only , the Durametric TPMS remaining life readings are reasonably accurate for 997.2 & 991. On my 2010 C4S I've logged the remaining life at every service I do ... oil change, brake bleeding, brake pad & disk change, etc for the last 7000 miles. I also logged the reading when I put on some MPSS last Jan. I see a downward trend in remaining life which I have assumed is due to battery discharge -- I have seen only flat and downward trends (less months remaining), never an increase in months remaining, so that is comforting. I try to log as much data as I can at each service interval since I primarily run the car at the track. Having a historical log helps track down any potential issues and gives me some data should I every need it for PCNA/PAG. (I do the same logging with a buddy's 991 and with my 2013 Cayenne diesel - not enough data to form an opinion yet, but trends look ok). If you start logging your data and find patterns that do not make sense, then, you've got something.

Having said all this, I am not convinced the absolute life remaining in TPMS is 100% correct, which is why I work with the deltas between service readings. By the way, the change Porsche made in the TPMS system (freq and sensor-receiver type) with 997.2 seems to have made for a more reliable and accurate system than in previous models, at least that is what I have heard from others who have more knowledge on this subject than I.

chris.hanle

Thanks very much. I will use it as a guide not a rule.