If nothing else, I think you've found the reason the app asks for location permission on the phone...

 

Yup. Noted...

I'm not a developer so the link between location services and barometer data didn't register.

 

On the basis that tyre pressures might change by 2 to 3 psi with a change in altitude from sea level to 5000 feet it won't affect me here in the UK. For every change in temperature of 10°C the tyre pressure will change by 1 to 2 psi.

In both cases is it a concern? Is the resolution and accuracy of the TMPS going to have you paranoid that you need to change the tyre pressures because a warning got flashed up on the screen for 2 psi?

 

On the one hand... Is it that big of a deal? Probably not.

On the other hand... Would I prefer that the device gave me accurate measurements? Sure I would. Particularly if induced inaccuracies - even if small - caused it to annoyingly set off warnings unnecessarily where it shouldn't have otherwise. I also believe it's of value to have a clear understanding of what the app is actually displaying, what the settings actually mean and how they should be set for typical use.

Curious what the other alternatives do in this regard.

 

I can't see any benefit in the app giving you the same tyre pressure if for example you are a visitor to Mexico city and you intend to stay a week or so or vice versa leaving Mexico city to ride at sea level. There will be a real change possibly over 3 psi. That is quite a lot, IMO. Something you would surely want to adjust?

I don't understand why it matters where you are in the world with a tyre pressure gauge that should show the pressure as it sees it and not have some weird adjustment applied ever.

 

They are handy. Especially while traveling.
I've had good success with the FOBO 2 for about 18 months now.

 

I have stated I think TPMS is a good idea. On cars with run flat tyres especially. It is actually a mandated fitment for cars across Europe can't remember date though.

The instructions as outlined above seems way too complicated which I put in the bullshit baffles brains type column.

 

I installed the FOBO 2 on my EGS. I do like the fact the it gives you an alarm if your pressure drops below the threshold you set. I also like the fact that I can have the app on multiple phones without going through the pairing process again. If one phone is close to the bike I can see the pressures on the other phone quickly even miles away. Not sure how the others work, but that's what this does for me. In the future I may look into having mounted TPMS installed, but don't see any point until it's time for new tires.

 

That was kind of my point. If you leave it in the default setting, there will likely be this error. However, if you set the Gauge Pressure setting to on then all should be good - assuming that your phone/cell tower provides acceptable barometric data. Most phones probably do these days... So probably not a big deal - assuming that the Gauge Pressure setting is on.

Well... as the manual indicates, unlike an actual gauge, the sensors measure absolute pressure relative to a vacuum. If you want gauge readings, then the setup has to account - like a gauge - for atmospheric pressure. This setup has to use the phone's or cell tower barometric data to provide that information (which any gauge accounts for by default). I'm guessing that the default setting accounts for situations where neither source of barometric data is available. They just set it to seal level (14.7) and call it the best that you can get - or good enough - under those circumstances.

Addressing the issue doesn't seem complicated. You may just need to set the Gauge Pressure setting to on. I just tossed out an explanation as to why I thought that it might be desirable/necessary and what you get if you do or don't.

Also... This statement in regards to the default setting...

... seems incorrect.

And... Like I said... The FOBO firmware/software seems to address this issue. I wonder what the alternatives do. I'm guessing they all work the same - the sensors measure absolute pressure relative to vacuum.

 

For S&G's...

Just took some comparison measurements...

Rear:

• Digital Pressure Gauge - 34.5 lbs.
• FOBO2 w/Gauge Pressure Setting ON - 33.9 lbs.
• FOBO2 w/Gauge Pressure Setting OFF - 33.6 lbs.

Front:

• Digital Pressure Gauge - 32.0 lbs.
• FOBO2 w/Gauge Pressure Setting ON - 31.6 lbs.
• FOBO2 w/Gauge Pressure Setting OFF - 31.3 lbs.

Altitude above sea level - 740 ft.

So... ~ 0.5 lbs difference between digital pressure gauge and FOBO2 with Gauge Pressure setting ON. Reasonable enough.

Assuming an increase of 2 lbs pressure per 5000 ft altitude, linear relationship, and doing the math... For 740 ft above sea level, tire pressure should have increased 0.296 lbs. Looking at the measurements with Gauge Pressure setting ON and OFF, the delta is 0.3 lbs. So, it appears altitude is being accounted for correctly with Gauge Pressure setting ON.

For what it's worth.