[Blady]

Hi there,

I took delivery of my iX1 roughly a month ago.It was delivered with winter tires installed. As winter is coming to a close, I had them replaced with summer tires a couple of days ago.
I didn’t really pay attention to the tire pressure, since the summer tires are brand new and have never been used. However, I randomly checked the app today and noticed that the actual tire pressure is way above the recommended value.
I’m not really sure what to do at this point, especially since it’s an EV and I’ve heard that slightly higher tire pressure can improve range.
Should I deflate them to the recommended level, or is it fine to leave them as they are?

What would you suggest?
Thanks in advance!

[John27]

Over inflated tyres leads to uneven tyre wear, reduced traction and increased risk of punctures or blowouts. I'd recommend checking the car's manual or the sticker on the car's door post that specifies the tyre pressure and stick to that. I assume BMW know what they are talking about when they determined the pressures?

However, I have little knowledge of EV's and so those better placed may be able to help.

[paulockenden]

I have a newish iX1 with summer tyres. Temperature here is 12 degrees C. My app is currently recommending 2.5 bar front and back (or rather 36.3psi, because I have my app set to use that, although it’s obvious from the strange jumps that the underlying units are actually Bar. ).

[catalink]

You have two settings: fully loaded (with 3.2) and partial loaded with 2.4. At least on my x23d.

So double check the sticker not rely on App itself. I have inflated them with 2.4 front and 2.2 rear and after driving for 5 minutes the app reported 2.4 and 2.2. After one hour of driving app reported 2.6 and 2.9 front and 2.6 and 2.4 rear.

So to be honest I kind of ignore the app.

[MMandov]

Unless you fill them with Nitrogen ( I avoid it as air adjusts them naturally), its normal for the pressure to increase after the tires get warmer.

Recommendations in the app/car are also variable and depend on climate.

I use my iX1 with just about .3 above recommended - 2.7 bar. When on the highway for long trips, it goes naturally to 2.9 and in slow speeds decreases so that is more comfortable on city streets, especially paved ones.

In general, safety (stability) is much more important than range.

[paulockenden]

Originally Posted by catalink

So to be honest I kind of ignore the app.

I’d recommend the opposite. The app takes temperature into account whereas the door sticker obviously doesn’t.

If the recommended pressure wasn’t variable with temperature then the app (and iDrive) would just give you a fixed value, rather than calculating a dynamic value.

[Rich807]

Manufacturers place recommended tire pressures in line with any given vehicle's max GVW. Very very often that means that unless you're loaded up with passengers in the back &/or heavy cargo, your rear tires are over inflated.

Here in the U.S.A that's easily seen by anyone owning a full-sized 3/4 or 1-ton pickup truck. Recommended tire pressure on the rears will be 80psi, which unless carrying a load of bricks in the bed &/or towing a super heavy tongue weighted trailer, the truck's rear tires will be massively overinflated to the point it's very easy to see wide portions of a given tire's outer edges will not be making contact with the road.

Although no manufacturer would ever recommend it in writing, what I've done with multi vehicles in the past is roll my vehicle's tires through a puddle of water onto dry pavement. Makes it easy to see over-inflation when it exists as the tire tread width will not all be making prints on the ground. From their I've aired-down until I got uniform tire tread-to-road contact.

[jadatis]

Electric vehicle sometimes have these high pressures as recomended, yust for higher actiradius of battery.
Sometimes even gives centrewear.

So its a choice you have to make.
Do you want minimum energy use or maximum comfort and gripp, or something in between.

If you give tyre-specifications, I can make you a cold pressure/ axleloadcapacity list.
In that I give 90% of calculated axleloadcapacity for the pressure, for max 160 kmph/ 99mph
Determined this in time, to give maximum reserve, and acceptable energy use, but acceptable comfort and gripp.

See you want it in bar and assume kg, but if different write it.
And if wanted for higher max speed used( wich you wont go over for even a minute), give it too.

Then your task is, and thats the most tricky part, to determine the axleloads in your use 99% acurate.
But you dont need to do pre-or after-calculations , yust read them from the list.

If calculated, carmakers nowadays often give only one arecomended for max permissable axle weights and max technical carspeed. But often , in case of oversised tyres, the Pr, mostly for liability reasons.
Then if you use lower, you cant hold them resoncible.
So you must realise that you have to determine it all accurate.

Need from tyres next, can be found on sidewall.

1. Maxload or loadindex

2. Kind of tyre to determine the referencepressure( Pr)
Here 2 choices I think
A. Standard load personscartyre Pr 2.5 bar/ 36 psi.
B. XL/ reinforced/ extraload personscartyre Pr 2.9 bar/ 42 psi
I think XL// because electric cars often have.

3. Less important , speedcode
Shall be Q or above for wich maxload is calculated for 160 kmph/ 99 mph.