[RocketVol]

Looking ahead to the US deliveries, in the US it is a legal requirement for the tire pressure label to only show the inflation pressures for a vehicle at its maximum load, a place where people only rarely drive. In the rest of the world there are usually a couple of pressures shown, a partial load and a full load number. And there can be significant differences between the 2. I have looked in the released UK manual and all it shows is a representation of what the label looks like, and has no data.

I prefer to run at the partial load numbers, where my car is usually loaded and the engineers intended. Here is what was in the UK manual:

Furkan would it be possible to get a picture of the tire pressure label on your ID.4 so we can see the other pressures? I hate to ask, and thanks again for all of the great videos, tons of useful and good information. thanks for blazing the trail for those of us still waiting!

John

 

[ID.Furkan]

'regular' 2.5 bar all around (rimsize not specified)
Fully loaded from my head 2.8 bar front and 3.1 at the rear.

I thought I had a picture, will snap 1 today

 

[Huey52]

Although I mostly still use Imperial measurements I concede that the metric system is better. However when it comes to atmospheric pressure I think pounds per square inch a much more relatable term than the nebulous 'bar.' But then I still lament the loss of cycles per second to 'Hertz.' 🤪 Anyway ...

2.5 bar = 36.26 psi Normal load all-around

2.8 bar = 40.6 psi Front Max load
3.1 bar = 45 psi Rear Max load

In the USA VAG is likely to placard-list 35/40/45 respectively. We 'mericans like simple numbers.

The fully loaded vehicle numbers are of course much higher than most will typically run.

 

[emtonsti]

Generally in EVs, higher tire pressure gives longer range, so it's pretty common to run 5+/- psi high to get a few more miles. Because of changes in temperature over weather and seasonal variation, and cold vs. hot measurements following driving. only those who check tire pressure more often will even notice, especially in ID.4 with no direct TPMS psi display.

There are always a few with longer daily drives, so post COVID, if someone wants to do some experimenting, it would be pretty easy to set tire pressure, say at two different psi, and note any difference in range over many days.

Post #3 at this Bolt thread has a list of some of the factors affected by tire pressure.

 

[ID.Furkan]

 

[RocketVol]

'regular' 2.5 bar all around (rimsize not specified)
Fully loaded from my head 2.8 bar front and 3.1 at the rear.

I thought I had a picture, will snap 1 today

Thanks Furkan, really appreciate the info and everything else you are doing.

If we are betting, I would say that the US placard will say 45psi all around, or might show a 40/45 split and will only have the full load numbers, not the partial ones.

One of the benefits of running the extra load tires is the ability to go to the higher max pressures without issue. On long road trips I typically bump the pressures up 5 pounds or so. I am sure the efficiency increase is negligible, but it makes me feel like I am doing something!

And I agree that most people will not notice the difference. Saw a study one time where they tested for that and most drivers could not tell when a tire was over 50% low, one of the reasons for mandating TPMS.

 

[RocketVol]

View attachment 1473

Great and thanks! Much appreciated!

 

[Huey52]

Because I'm anal about proper tire pressure (no surprise there) I can't help but notice the tires of others when driving or parking and am amazed/mystified at how low pressure some people will go. 🤷‍♂️

... And I agree that most people will not notice the difference. Saw a study one time where they tested for that and most drivers could not tell when a tire was over 50% low, one of the reasons for mandating TPMS.

 

[RocketVol]

To bring this one back up again. Looking at the tire pressure placard on my FE, it says 42 psi all the way around. When I checked they were all at about 46 from the dealer so I dropped them to 42. Then perusing through the erWin files I found this these tables. My tire pressure sticker says 11A010000-D, while the one Furkan posted is a -K so his lines up, but the NAR ones don't. But even with there not being a table we can tag to the -D label, it looks to me like at half load we should be running 36 or 39psi all around. The US tire pressure labels list pressures at max load and I can't even make the 42 on mine match these tables, and I am betting that the -L is AWD. Thoughts?

If people are not happy with the 20's ride they might be way too high from the dealer and dropping them should help some

 

[Neil]

The US tire pressure labels list pressures at max load and I can't even make the 42 on mine match these tables, and I am betting that the -L is AWD. Thoughts?



View attachment 3476

Table has an obvious error for L- at full load. Rears should be at 46psi. The table indicates 469psi, which is probably a bit too high.

 

[RocketVol]

Table has an obvious error for L- at full load. Rears should be at 46psi. The table indicates 469psi, which is probably a bit too high.

I think they dropped the decimal point to make it fit! And they are still off by .5 psi. I have found several small errors in the manuals, I think they are still evolving

 

[Keowee]

For the data nerds .... test report on coast down resistance as an indication of range impact for EVs. In this testing, tire pressure set at 2.0, 2.2 and 2.4 bar had an insignificant impact on coasting resistance. More of an impact at slower speeds. So I guess inflate for the ride comfort you want.

They also look other factors: 1) ambient air temperature > higher better and 2) wet road conditions < much worse with range impact 6-12%.
https://www.sae.org/publications/technical-papers/content/2020-01-1068/ (abstract, but you can read some free in preview)

 

[Huey52]

Dealerships typically overinflate as they recognize many/most won't thereafter check same and better to err on too much vs. too little (more tire wear but safer operation than under-inflated). Either that or they just don't bother to check the vehicle spec's.

btw: now coming into NA warmer weather do be sure to let off some air to re-achieve the nominal placard setting for your driving needs.

 

[stowington]

Dealerships typically overinflate as they recognize many/most won't thereafter check same and better to err on too much vs. too little (more tire wear but safer operation than under-inflated). Either that or they just don't bother to check the vehicle spec's.

btw: now coming into NA warmer weather do be sure to let off some air to re-achieve the nominal placard setting for your driving needs.

Not to mention the hassle of having to more carefully monitor the pressure of all the cars on their lot if they "only" inflate to the sticker spec.

 

[theboomr]

Yeah, I was just noticing a couple days ago that the door sticker says 42 across the board, while tires themselves say 50 max psi, so I went ahead and checked and all 4 of them were right at 49 or 50. I bled them a little to put them at about 45, I think, but that spreadsheet is interesting, I'll probably adjust to those values.

 

[RocketVol]

Yeah, I was just noticing a couple days ago that the door sticker says 42 across the board, while tires themselves say 50 max psi, so I went ahead and checked and all 4 of them were right at 49 or 50. I bled them a little to put them at about 45, I think, but that spreadsheet is interesting, I'll probably adjust to those values.

I am going to drop mine today to the 36 numbers, that is what the engineers intended. I will almost never run max load and if I do for any length of time will bump them up. The door stickers are simplified here and just show one pressure, max load. Same thing with the Phaeton, only one set of high numbers for the NAR, but a couple of options based on load for the rest of the world. I run the world numbers and it rides better than the high pressure door sticker ones.

 

[theboomr]

I am going to drop mine today to the 36 numbers, that is what the engineers intended. I will almost never run max load and if I do for any length of time will bump them up. The door stickers are simplified here and just show one pressure, max load. Same thing with the Phaeton, only one set of high numbers for the NAR, but a couple of options based on load for the rest of the world. I run the world numbers and it rides better than the high pressure door sticker ones.

So it should be 36 all around for half load, then full load you just up the rear tires to 39?

 

[Neil]

So it should be 36 all around for half load, then full load you just up the rear tires to 39?

Where do you see that? Doesn't the -K table apply to your FE? As I read the table, at full load it specifies 39 front & 45 rear.

 

[ozkayamur]

Where do you see that? Doesn't the -K table apply to your FE? As I read the table, at full load it specifies 39 front & 45 rear.

This makes sense since with full load most of the weight is in the rear.

I would not overanalyze it too much. Somewhere between 36 and 45 should be good

 

[theboomr]

Where do you see that? Doesn't the -K table apply to your FE? As I read the table, at full load it specifies 39 front & 45 rear.

I haven't looked at my door sticker to see if mine is -D like @RocketVol has, but assuming that mine is also -D, no, our US ID.4s do not match Furkan's. I'm assuming that the euro cars might ship with different tires across the board, for whatever reason? I can't remember if that's been discussed yet.

But also for some reason I just had a really hard time absorbing the info in these tables, so I'm not sure which part I looked at to get my numbers lol.