Switch to normal is300h ?

[DBIZO]

3 hours ago, Mr_Groundhog said:

 

So, to summarise: reccommended measurements assume 20 degrees... for each +10 degrees on the tarmac, you should lower the pressure 0.1 bar, and vice versa, to compensate the change. 🙂  In the winter, you would probably have to pump up to 2.6 or 2.7 bar in order to have your wheels at that reccommended value of 2.5    

I may be slow, but don't follow this. Ambient temperature should not change the target pressure on the manometer. Yes, you need to check and adjust regularly, whenever the temp changes a lot. Yes, if you anticipate driving into much colder weather (say you're at the bottom of the Alps), or it's early summer morning and you're about drive in 40C heat at speed, of course you can make those calculated minor corrections. Otherwise pump to 36 psi or whatever your tyre guidance says. 

[Mr_Groundhog]

1 hour ago, DBIZO said:

I may be slow, but don't follow this. Ambient temperature should not change the target pressure on the manometer. Yes, you need to check and adjust regularly, whenever the temp changes a lot. Yes, if you anticipate driving into much colder weather (say you're at the bottom of the Alps), or it's early summer morning and you're about drive in 40C heat at speed, of course you can make those calculated minor corrections. Otherwise pump to 36 psi or whatever your tyre guidance says. 

It's because it is a relative measurement, not an absolute one. I.e. the difference between ambient pressure vs tyre pressure, so it is subject to changes in ambient pressure. Otherwise manometres would have to carry a pressurised compartment of their own 🙂  So if your tyre pressure is X, then the manometer will show X minus ambient pressure.

[Nickyt211]

I purposefully didn’t buy an f sport due to the harsher ride. Can the dealer not allow a test drive of another trim level. I would think for the price of an f sport you should be able to get a nice level trim.

Min is only a 2013 luxury but I love it. 

[mikejt]

When did anyone use a manometer to check tyre pressures. 

[Mr_Groundhog]

1 hour ago, mikejt said:

When did anyone use a manometer to check tyre pressures. 

I use a manometer to do so, every two/three weeks or so. And before every long ride. I keep it in the boot. Don't you ?

[mikejt]

I use a pressure gauge as it's a little more convenient.

[Mr_Groundhog]

3 hours ago, mikejt said:

I use a pressure gauge as it's a little more convenient.

Maybe we're talking about the same thing. This is the one I bought back in the day, it works really well: https://www.amazon.co.uk/gp/product/B01EN36I32?psc=1

I also have a 12v pump which i keep in the garage for when i need to top them up

[mikejt]

Surely that's a bourdon tube pressure gauge not a manometer.

[Mr_Groundhog]

10 hours ago, mikejt said:

Surely that's a bourdon tube pressure gauge not a manometer.

well the definition of manometer is a device to measure pressure...

[DBIZO]

1 hour ago, Mr_Groundhog said:

well the definition of manometer is a device to measure pressure...

I think Mike's point is that tyre pressure is measured by a different kind of pressure gauge, not a manometer, the working principle of which is liquid displacement. Which made me realise I just assumed that's how they work, but in fact I don't know.

[mikejt]

https://www.google.com/search?q=bourdon+tube+pressure+gauge+working+principle&oq=bourdon+tube+&aqs=chrome.2.69i57j0i512l14.6263j1j7&client=ms-android-samsung-ss&sourceid=chrome-mobile&ie=UTF-8&chrome_dse_attribution=1

 

 

[mikejt]

https://www.electronicshub.org/manometer-vs-pressure-gauge/#:~:text=With a pressure gauge%2C you,lies in their working principle.

[Mr_Groundhog]

We're splitting hairs here?

From those links above:

Quote

However, it has to be noted that all manometers are pressure gauges. On the contrary, all the pressure gauges cannot be manometers.

Anyway, I can see there are some thin-skinned forum members. I won't be around to bother you no more, don't worry.

[mikejt]

It's not splitting hairs so don't be offended. It's because of my background in process control instrumentation. Pressure gauges are routinely used to measure pipeline pressure but also differential pressure  is also measured  eg across filters to see when need changing. Manometers can be used when setting up gas fire pressures in inches water gauge, say 8" difference in column height between the test connection on one side and atmsphere the other.

If you think think this forum is bad you should try the BT forum. I went there seeking advice on hooking up my new broadband hub/router and got roasted by a regular who accused me of being a younger generation who wanted everything on plate (I'm 73) etc. etc. Senior moderators were involved who apologised but it left a bad taste.

If you are offended please accept my personal apologies.

[Mr_Groundhog]

15 hours ago, mikejt said:

It's not splitting hairs so don't be offended. It's because of my background in process control instrumentation. Pressure gauges are routinely used to measure pipeline pressure but also differential pressure  is also measured  eg across filters to see when need changing. Manometers can be used when setting up gas fire pressures in inches water gauge, say 8" difference in column height between the test connection on one side and atmsphere the other.

If you think think this forum is bad you should try the BT forum. I went there seeking advice on hooking up my new broadband hub/router and got roasted by a regular who accused me of being a younger generation who wanted everything on plate (I'm 73) etc. etc. Senior moderators were involved who apologised but it left a bad taste.

If you are offended please accept my personal apologies.

Thank you for clarifying. No I wasn't offended in the slightliest but I felt the debate on manometer vs gauge was getting too heated for what it was actually worth (I can now see it was only my perception).

I guess I'm too used to seeing people getting belligerant online over small stuff these days ...so didn't wanna get into it. I much appreciate your comment by the way.

[DBIZO]

On 3/14/2023 at 5:59 PM, mikejt said:

It's not splitting hairs so don't be offended. It's because of my background in process control instrumentation. Pressure gauges are routinely used to measure pipeline pressure but also differential pressure  is also measured  eg across filters to see when need changing. Manometers can be used when setting up gas fire pressures in inches water gauge, say 8" difference in column height between the test connection on one side and atmsphere the other.

If you think think this forum is bad you should try the BT forum. I went there seeking advice on hooking up my new broadband hub/router and got roasted by a regular who accused me of being a younger generation who wanted everything on plate (I'm 73) etc. etc. Senior moderators were involved who apologised but it left a bad taste.

If you are offended please accept my personal apologies.

Great, a question for you then: so what exactly are we measuring when taking readings of the tyre pressure at a garage? It is an absolute level of pressure in the tyre (at a given internal air temperature), right, as opposed to a differential pressure to actual atmospheric (affected by elevation, ambient temp)?