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So, the instructions in the manual state to ride until the TPMS turns on, then compare that value to a gauge (any gauge, it doesn't have to be especially accurate other than in reading a change in pressure). Then add or remove the psi/bar difference. For example:
  • Rear TPMS reads 2 psi high at 44 psi
  • Your gauge reads 48
  • Remove 2 psi so gauge reads 46
  • Next time the TPMS turns on, it should now read the correct 42 psi
When I add air in my garage I use a chart to compensate the PSI to 68 degrees.
When I leave for a trip I look at my TPM readings to double check I set the pressure correct.
During the trip I only look at the TPM reading first thing in the morning and don't check with a gauge.
Here's the chart I keep next to the compressor at home.

Rectangle Font Parallel Screenshot Pattern
 

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I'm not 100% sure of this but I understand that the TPM reads relative, corrected pressure, meaning that what you see on the TPM readout may not be actual pressure. In other words, if it reads say 40 psi as you leave your parking spot with "cold" tires, at any point during the day it should show the same number, no matter how hot your tires are. This way, you know you aren't losing air, which is fundamentally what the TPM is for. In this situation, taking your tire pressure with a good gauge after a lengthy ride, the gauge would probably show 43-44psi while the TPM would still read 40.

My RT - on which I have more miles that the R - shows 38 & 42 (F & R - my pressured pressures) when cold, and after an enthusiastic ride the TPM still reads 38 & 42, but a quality gauge reads about 41 & 44.

Very broadly, you want your cold tire pressure to be whatever it takes so that a hot tire pressure is about 3-4psi higher than cold, but this depends on rider weight, type of riding, altitude, bike & tire type, whether you want optimal handling or optimal comfort, whether you are aiming for max grip (and in which direction) or max life, ambient temperature etc - a whole raft of variables. Ambient temp is a good one - it's very rare that there isn't 20°F (sometimes a LOT more) difference between leaving the house in the early morning and at say 2pm. I've seen as much as 70°F difference between 6am and 3pm - below freezing at high altitude and upper eighties on the plains.

Dave Moss and several others have some good explanatory videos on the topic.

And while we are at it, having a TPM showing PSI decimal places is totally pointless. Setting the tire to a decimal place, if you are that good, may make a difference.
 

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Frankly, I just use TPMS as an indication of current pressure. I know what my manual gauge said when it checked. Any difference in TPMS just becomes a mental note. If it goes up/down too much I stop and check. So far, this only happened when I left for home in sub-freezing weather, and at the first gas stop (it got warmer), my tire pressure went up substantially and I had to bleed off the excess pressure.
 

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Before every ride I check my tyre pressures, tyres (for damage/wear) and chain for oil (on those that need it) so the only thing my TPMS does is tell me when I have a flat.
 

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Mark – Moderator 2015 R1200R-LC Exclusive
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Before every ride I check my tyre pressures, tyres (for damage/wear) and chain for oil (on those that need it) so the only thing my TPMS does is tell me when I have a flat.
I use my Roadster as a daily runner for all sorts of things, in addition to going for a ride, so I’d be wasting too much time doing all these checks before every ride.
Every few days I’ll have a look at the readings to see if I need to puff a little top up into the tyres, knowing the RDC will let me know if there’s been an alarming change in pressure.
 
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I use my Roadster as a daily runner for all sorts of things, in addition to going for a ride, so I’d be wasting too much time doing all these checks before every ride.
Every few days I’ll have a look at the readings to see if I need to puff a little top up into the tyres, knowing the RDC will let me know if there’s been an alarming change in pressure.
Same here.
 

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I use my Roadster as a daily runner for all sorts of things, in addition to going for a ride, so I’d be wasting too much time doing all these checks before every ride.
Every few days I’ll have a look at the readings to see if I need to puff a little top up into the tyres, knowing the RDC will let me know if there’s been an alarming change in pressure.
I have five bikes so the same one might not be ridden for over a week. I don't want to find I have a flat after I've left home as I live on a hill. :mad:
 

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I have five bikes so the same one might not be ridden for over a week. I don't want to find I have a flat after I've left home as I live on a hill. :mad:
If you use the side stand, you’ll know when you pop out to the bike if it has a flat. The bike will be lying on its side. :oops:
 

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Ok, just been reading this somewhat old thread and feel the need to add my 2 cents. Sorry, can’t resist. From my perspective the perfect answer to “what should my pressure should be” is ill defined with multiple, interactive variables some of which are always changing. These include but are not limited to ambient temperature (this will change with the day), how much heat are you going to put into the tire (track day riding vs short distance casual riding), tire brand/model and compound, riding surface (wet, dry, tarmac type, dirt?). When I was racing there was always a tire guy at the track who would help with where to run the pressure in your slicks at a given track and time of day. He worked for the tire company. His advice would change as the day warmed up and it was always somewhat of an iterative loop. He’d say “try this and get back to me”. Some guys liked to slide a lot and some didn’t. Back then tracks near the shore like Daytona would have some amount of sea shells in the tarmac. This gave gobs of traction but wore the tires out very quickly. Pressures were adjusted accordingly to balance traction and wear given the track surface. It could all make your head hurt more than reading this thread. The good news for us is that unless you ride like Fabio Quartararo, perfection is not needed. I’m also relatively sure that his team struggles to find it every time he goes out. So, what really matters most that we can actually measure and control? Warmed up/hot temp pressure. You already know that. The tire guy at the track was only ever concerned with hot/operating temps. That’s easy to check at a race track but you may be a long way from your compressor in everyday riding by the time it’s warmed up. I’m pretty sure the recommended cold temps are meant to account for average tire warming so probably just fine for most conditions or at least a good place to start. If you are doing a track day or just want to venture down the tire pressure rabbit hole you can iterate based on how it’s working once hot. I do think a good gauge is essential (not TPM). I have 1 good gauge and one really, really good gauge that you don’t need. The good gauge is from Motion Pro and is calibrated to be accurate within 0.6 psi. It costs about $100 and I’ve had mine for years with no issues. My crazy good gauge is a Fluke 717 110G pressure calibration meter. This is accurate to within 0.05 psi. It also costs over $2000. Normal people don’t need this (I’ve never been accused of being normal). I also have a garden variety $3 gauge in my ride along bike kit that I’ve verified to be reasonably close to the good gauge. What about the original question regarding the TPM? My brain isn't temperature corrected. Personally, I’m with the others who said that they only use this as a coarse indicator that something is woefully wrong. I may look at it if something feels a bit squirrelly while riding.
 

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The only people I’ve known who have a justified reason to be anal about tire pressure are those doing track days or riding aggressively on back road. Most never have a second thought as long as cold pressure is as specified (or preferred).
 

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I’m anal about it because correcting the TPMS to standard temperature bugs the snot out of me. The sensor measures absolute pressure. How about giving me that and let me worry about the tires and my driving needs?
 

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Mark – Moderator 2015 R1200R-LC Exclusive
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@Dougl - because the vast majority of road riders want to know their ‘cold’ pressures and how they compare with the specified ‘cold’ temperature pressures.
A temperature correcting sensor means they can do this at a ride stop or even while riding, rather than only before a ride when the tyres haven’t heated up.
It seems you’re over-thinking it. The pressure displayed while riding with tyres warmed up will be the same as measured before the ride (subject to any air loss during the ride), and can be validly compared with the manufacturer’s spec without any mental arithmetic to allow for the hotter tyre. Simple as that.
If your ‘riding needs’ are such that you feel you want a higher (or lower) pressure, inflate to that and the readout will always display the value as it would be ‘cold’. That’s your benchmark.
 

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What bugs me about TPMS sensors in general is that they don’t wake up until acceleration is detected. I do understand that this is done to conserve battery life on the sensors, but it also means that I won’t get a reading until I’ve left my driveway and ridden away. They could tweak the accelerometers to wake up when the bike/car is rolled a little bit but they might wake up when parked on a windy day and that wouldn’t be good for battery life. Just FYI, here’s how they work:
https://www.utmel.com/blog/categories/sensors/what-are-tpms-sensors
The issue with different altitudes is as mentioned before and the fact that the sensor doesn’t have a means of measuring the ambient pressure where you are. My fancy meter has a zero button to correct for this based on local ambient pressure. Not advocating that anyone needs this and you can rest assured that I didn’t pay for this meter. I saved it from going into the bin when one of my engineering labs was being decommissioned. Here’s a useful table for those not living at sea level:
https://www.nwflowtech.com/media/0y0aizb3/nwft-barometric-pressure-vs-altitude-table-122120-v2.pdf
 

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“It seems you’re over-thinking it.”

In this as in most things, which is why I am (was) a scientist- outlet for OCD. There are a number of things that hang me up about this. BMW says to add the TPMS differential to the gauge tire pressure. I set my cold front tire to 37.5 psi with a gauge. Then I go out and the TPMS differential is +2.5 psi. So BMW wants me to add air until the gauge reads 40 psi. Not doin’ that. Neither does the dealer. The head mechanic has been at this since way before TPMS. The TPMS measures absolute pressure, which is strictly referenced to zero psi. My understanding is that indicated tire TPMS is referenced to sea level (14.7 psi). The indicated gauge tire pressure is the difference between the tire pressure and atmospheric pressure. At sea level at 20C, the TPMS and gauge readings should be the same. I haven’t seen this anywhere, but I assume tire gauges are referenced to sea level when they are calibrated. At 5000 ft where I live, the gauge applied to the same tire (no leaks) will read 2.5 psi higher than at sea level at the same temperature. Question: is the manufacturer’s recommended inflation pressure meant to be set with a gauge at any altitude? I never see anything about pressure or temperature regarding recommended inflation pressure.
 
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