TPMS does not measure tire pressures.
12-05-2018, 09:36 AM
#11
Permanent S Mode Member
Just a few more comments. A lot of folks seem to think that TPMS was designed to let them know when they have to put air in the tires. This couldn't be further from reality. TPMS' primary purpose is to act as a last resort and alert the driver of a significant loss of pressure in one or more tires. It does not preclude one from regularly checking their tire pressure. As said, these systems alert at around a 20-25% loss of pressure if operated correctly, and that's primarily meant to detect an unusual loss of air due to a puncture etc. Unfortunately, many car owners neglect this basic maintenance requirement and that's what persuaded officials to make TPMS mandatory in the USA. Some manufactures still use a direct system with sensors, but that incurs extra cost to the customer. For example a second set of sensors is needed for a winter wheel setup or the complete sensors have to be replaced if the battery dies. This extra cost is the primary reason Audi and others have gone with the indirect system. They have proven to be accurate enough to satisfy the law. Mainstream models will more and more go into this direction. Direct TPMS is still something that can be found on higher performance cars. In those cars it typically not only shows the current pressure, but also the tire temperature and the purpose of those is so that the driver can keep an eye on the hot tire pressure and temperature while busting around a racetrack for example and make necessary adjustments to achieve even pressure and temperatures. The RS models starting with MY19 will have direct TPMS standard for example. The gen 2 R8 had it standard already. For everybody else, OP is correct in one point, check your tire pressure regularly and visually inspect your tires. It's the only thing that keeps you on the road.
Anecdotally, I have two vehicles, a 2006 with a sensor system that only gives warning when a tire pressure is too low, and a 2018 with sensors providing real-time pressure numbers. The funny part is the vehicle that provides tire pressure numbers receives more care from me as I pump the tires as soon as they get a couple of pounds too low, and I won't/can't do that with the other one. So, in the long run, the vehicle with costly sensors saves me money because I keep its tires properly inflated at all times. So Audi, if you truly care about my wallet, put these sensors in, or at least make it an option and I'll tick that box.
12-05-2018, 09:55 AM
#12
AudiWorld Super User
The fact that so many "lesser" cars come equipped with direct systems providing close to real-time tire pressures has a lot to do with people's frustration or disappointment with Audi's approach. Audi's line saying they are saving us money in the long run is cute but if nobody is asking for that, they are solving a problem that didn't to be solved and using the software method ends up being an Audi cost cutting measure only. Bottom line is, yes we are spoiled, and we like seeing tire pressure numbers as we cruise down the highway.
Anecdotally, I have two vehicles, a 2006 with a sensor system that only gives warning when a tire pressure is too low, and a 2018 with sensors providing real-time pressure numbers. The funny part is the vehicle that provides tire pressure numbers receives more care from me as I pump the tires as soon as they get a couple of pounds too low, and I won't/can't do that with the other one. So, in the long run, the vehicle with costly sensors saves me money because I keep its tires properly inflated at all times. So Audi, if you truly care about my wallet, put these sensors in, or at least make it an option and I'll tick that box.
Anecdotally, I have two vehicles, a 2006 with a sensor system that only gives warning when a tire pressure is too low, and a 2018 with sensors providing real-time pressure numbers. The funny part is the vehicle that provides tire pressure numbers receives more care from me as I pump the tires as soon as they get a couple of pounds too low, and I won't/can't do that with the other one. So, in the long run, the vehicle with costly sensors saves me money because I keep its tires properly inflated at all times. So Audi, if you truly care about my wallet, put these sensors in, or at least make it an option and I'll tick that box.
Your anecdote is just kinda saying that you are lazy
. All it takes is a $20 tire gauge from your local AutoZone or what not and regularly check the tire pressure. I have a reminder set in my calendar to check it every second Saturday and that's what I do. I have a little compressor in my garage, but most of the time I'm only .5 to 1 psi low, which is 4-8 pumps using bicycle floor pump. All in, it takes less than a minute to check all four tires and a couple of minutes more if I have to put air in. Yes, being able to read it from the dash is certainly very convenient and I will appreciate it in my upcoming C63 S, but there are bigger fish to fry than fretting over having to pick up an actual tire gauge.
12-05-2018, 10:01 AM
#13
Club AutoUnion
Our Acura RDX has the direct readout on all 4 tires and my wife gets upset when the driver rear sensor shows its 3 psi lower than the other 3 — this despite the fact that I show her on my AccuGuage tire pressure gauge that all 4 tires are showing 35 psi. I know it’s the TPMS sensor in that wheel and it’s not worth whatever Acura would charge me to replace that sensor.
I’ve told her that as long as it’s the only one showing a 3lb. pressure difference, the tire is OK. I still check both cars weekly with the AccuGuage - but not when she’s around. As someone posted earlier, it’s up to me to keep our cars safe and roadworthy.
I’ve told her that as long as it’s the only one showing a 3lb. pressure difference, the tire is OK. I still check both cars weekly with the AccuGuage - but not when she’s around. As someone posted earlier, it’s up to me to keep our cars safe and roadworthy.
12-05-2018, 10:17 AM
#14
Permanent S Mode Member
12-05-2018, 11:55 AM
#15
AudiWorld Super User
Agreed 100%. And I have all these things too (compressor, bicycle pump, multiple gauges) but I do like the built-in air gauges too. It's just another gauge, just like my built-in fuel gauge that replaces the wooden dip stick that people once used to gauge how much fuel was left in the tank.
12-05-2018, 04:19 PM
#16
AudiWorld Member
It could be that while tire pressure is important, oil level is way more important and we all have had sensors read bad. So for oil I too would prefer a dipstick. But I also check my own tire pressure as even the Discount Tire guys who do thousands of tires somehow get it wrong 9 times out of 10.
12-05-2018, 05:06 PM
#17
AudiWorld Super User
It could be that while tire pressure is important, oil level is way more important and we all have had sensors read bad. So for oil I too would prefer a dipstick. But I also check my own tire pressure as even the Discount Tire guys who do thousands of tires somehow get it wrong 9 times out of 10.
12-05-2018, 06:03 PM
#18
Club AutoUnion
It could be that while tire pressure is important, oil level is way more important and we all have had sensors read bad. So for oil I too would prefer a dipstick. But I also check my own tire pressure as even the Discount Tire guys who do thousands of tires somehow get it wrong 9 times out of 10.
Whenever we get our RDX back from the Acura Dealer,their service guys have inflated the tires to between 38 and 40 psi. I’ve brought that to the Service Managers attention every time but they keep doing it. Last time, while the RDX was still in the garage pickup area, I walked over with my tire gauge, measured the pressure and released the excess air in front of the service writers, while shaking my head.
12-05-2018, 06:14 PM
#19
AudiWorld Super User
Whenever we get our RDX back from the Acura Dealer,their service guys have inflated the tires to between 38 and 40 psi. I’ve brought that to the Service Managers attention every time but they keep doing it. Last time, while the RDX was still in the garage pickup area, I walked over with my tire gauge, measured the pressure and released the excess air in front of the service writers, while shaking my head.
12-05-2018, 06:28 PM
#20
AudiWorld Senior Member
Thread Starter
The B-pillar label (which I set them by) says 42. Owner's manual says 42 for maximum load, and 38F 35R for normal load 2-3 people) So, I'l roll it back, and stick a label near the other showing what it really needs to be. Leaving TPMS un-set for now to see if it picks up on the reduction.
Last edited by Waggin; 12-05-2018 at 07:03 PM.