TPMS alarm settings?

[Bird325]

After ruining a tire due to a puncture and unknown pressue drop, I added an aftermarket TPMS to my Gen II GTS wheels to let me know right away when I had a problem. I'm looking for advice on where to set the minimum pressure and maximum temp alarms. I normally run my PS2's at 30psi (cold) and have the alarm set to 25psi.

We had a club gathering last night and it was COLD. All 4 tires were setting off the alarm when I left from the event due to the cold weather and the car sitting outside for hours. I'm wondering how low the pressure can be and still not damage the tires? Also, on the temperature side of the alarms, how high can that safely go on PS2's?

 

[Steve-Indy]

To me, here are a couple of issues here worth discussing. Since the PS2's have a cold tire pressure recommendation of 29 psi...I personally would set the low at anything below 25 psi...and the high at 40 psi for street use in MY climate (noting that warm climates/track use make a big difference with a max sidewall loading of 51 psi). Assuming that you fill your tires with air, you can roughly estimate a 1.0 psi rise for each 11 degrees F rise in equilibrated temp. For a REAL answer, I would ask Luke at Tire Rack.

I would also add that as the weather changes, I regularly adjust ALL tire pressures on all cars just in case that I decide to drive one. So, as cold approaches, I boost pressures on daily drivers to compensate...and still allow a wide margin of safety on both ends. And YES, I spend a lot of time messing with tire pressures. Cars that will not see frequent use in cold weather have 'Post It Notes" on windshields reminding me to adjust pressures before driving on the day of said drive. Thus, in cold weather such as you experienced, I would have boosted tire pressures to compensate for the expected conditions...and put a note on windshield as a reminder just in case my next drive came on a warm day.

I have not searched for a specific numerical temp warning for PS2's...but, the 2010 ACR's Sport Cups come with a warning printed in owner's manual concerning pavement temps below 50 degrees F.

I will be interested in the thoughts of others.

 

[Bird325]

Thanks for the input. I need to get a racing guage for my compressor so that I can add and remove air quickly and easily. I usually run at 28 cold with a 4 psi gain as the tires warm up. I still got 4 psi gain last night, but they started out way too cold and low on pressue. Here in Texas, I've found that the 28 starting point usually puts me at 32 when warm and driving normally ... a little more aggressive puts it up another couple of PSI. For Track days, all bets are off and they get adjusted at the track to the conditions and then again before the drive home.

I think leaving them at 25 alarm pressure is probably a good idea. I'll just add some air when it's cold (for here) and bleed it back off when the weather returns to normal. For instance, last night was cold... tonight we're going to get a little snow ... and by Wednesday, we're back up to 69 and sunny. I think I'll just leave the Viper in the garage when it's going to be approaching freezing!