[UnluckySaxon]

Hiya all,

I cannot seem to get any ideal recommendations about what pressures should be used in these except the 2.8 bar the car / door recommend. Michelin themselves were entirely bland also

The set up is 255/35/R19 & 255/40/R19

Thanks in adv

[ramparts]

Mine ( at current temp at 20C ) are at 43 PSI.

They were 41 when I set them when it was 6C outside

[HeebieJeebies]

Originally Posted by davidoff86

Mine ( at current temp at 20C ) are at 43 PSI.

They were 41 when I set them when it was 6C outside

Christ! That’s a bit high, not particularly hedge backward high, but I’d say a tad overinflated.

Not got them on my G21, but I’ve got them on another car (rears slightly wider than OP). I run them at 34psi all year, work well, fast, slow, cold or warm. No expert here and I’ll succumb to superior knowledge over the the car manufacturers billions of £/$/€ in R&D for recommended pressures

[ramparts]

Idrive wants them at 48 !

It's basically mid way between comfort and "full loaded"

They feel very good at these pressures, and I've checked the treads on gravel and nice even contact

[Drew474]

38 psi. My Bridgestones beforehand were set at the recommended pressure and they were worn in the middle after 7000 miles.

[HeebieJeebies]

Originally Posted by davidoff86

Idrive wants them at 48 !

It's basically mid way between comfort and "full loaded"

They feel very good at these pressures, and I've checked the treads on gravel and nice even contact

As I say, no expert, but if the experts want them at 48, 48 it is

[ukbeemerboy]

Originally Posted by HeebieJeebies

As I say, no expert, but if the experts want them at 48, 48 it is

That’s way too high. Rears are normally around 42 psi and fronts around 40. It will depend on engine what the pressures are recommended to be but at 48 psi you’ll wear the middle of the tread in no time.

[HighlandPete]

Originally Posted by davidoff86

Idrive wants them at 48 !

It's basically mid way between comfort and "full loaded"

They feel very good at these pressures, and I've checked the treads on gravel and nice even contact

Have you got the right tyres and speed selected? 48psi is very high.

[ramparts]

Originally Posted by HighlandPete

Have you got the right tyres and speed selected? 48psi is very high.

Yeah, that's the "fully loaded" option earlier.

Remember these change based on outside temperature! I'm sure when I check in the morning it'll be like 45/46

[Charlie (Wessex)]

48 psi? I looked at my Mich CrossClimate and they state max pressure is 50 psi. Wonder if the PS4S is similar - if so 48 is too close to 50 for my liking!

[HighlandPete]

Originally Posted by davidoff86

Yeah, that's the "fully loaded" option earlier.

Remember these change based on outside temperature! I'm sure when I check in the morning it'll be like 45/46

Ah, I understand. A hot, fully loaded working pressure.

[Charlie (Wessex)]

Interesting to see what Michelin say. For my M340i they are saying 36 PSI

https://www.michelin.co.uk/auto/tips...essure-for-bmw

This is a fair bit less than what iDrive is saying. Who do you trust? Michelin or BMW?

[a.summers86]

Originally Posted by Drew474

38 psi. My Bridgestones beforehand were set at the recommended pressure and they were worn in the middle after 7000 miles.

Common problem with the 255 wide turanzas. They wear unevenly even when run at correct pressures. Even running them lower or higher results in the same issue.

The middle of the tyre bellows slightly at higher speed meaning the contact patch is more on the middle.

Nothing you can do I’m afraid.

[Charlie (Wessex)]

It might also be worth thinking about RFT and non-RFT. Here is an old thread from a Z4 forum that discusses it - https://z4-forum.com/forum/viewtopic...ed%20pressures - that I think has to have some truth in it.

Gone and looked at the sticker in the door, and it says for 5 up 3.0/3.5 Bar, But 3.5 Bar is 51 PSI which is more than what Michelin CC says is the max pressure. I have to say that while BMW recommend * marked RFT, it is incredibly dangerous of them to not mention pressured for non-RFT.

So looking at the pressures for "normal" load, the door sticker says 2.7 Bar = 39psi. Michelin, as I earlier posted, say 36psi. I'd be interested to see what my RFTs say is the max pressure.

[themnmd]

Aren't recommended tire pressures listed inside the driver door , specific to size?

[Charlie (Wessex)]

Yes, but they are for recommendation tyres. Mine is recommending full loads be 50.8 PSI but my tyres say max inflation is 50 PSI {non RFT}

[tyranniux]

Originally Posted by Charlie (Wessex)

It might also be worth thinking about RFT and non-RFT. Here is an old thread from a Z4 forum that discusses it - https://z4-forum.com/forum/viewtopic...ed%20pressures - that I think has to have some truth in it.

Gone and looked at the sticker in the door, and it says for 5 up 3.0/3.5 Bar, But 3.5 Bar is 51 PSI which is more than what Michelin CC says is the max pressure. I have to say that while BMW recommend * marked RFT, it is incredibly dangerous of them to not mention pressured for non-RFT.

So looking at the pressures for "normal" load, the door sticker says 2.7 Bar = 39psi. Michelin, as I earlier posted, say 36psi. I'd be interested to see what my RFTs say is the max pressure.

That makes sense to me. Perhaps a good idea would be to have a look at the pressures recommended for the 3er xdrive saloon vs the g80 m3 xdrive saloon which I think has the PS4S as standard? This should give you some idea if the difference required. Wpuldnt surprise me if the michelin data is correct though.

[P-ToK72]

Originally Posted by a.summers86

Common problem with the 255 wide turanzas. They wear unevenly even when run at correct pressures. Even running them lower or higher results in the same issue.

The middle of the tyre bellows slightly at higher speed meaning the contact patch is more on the middle.

Nothing you can do I’m afraid.

Agree with this, I had BS Potenzas on my recently traded in M135i and after less than 10K miles the fronts were near the limit in the middle.

On the F40 forum (babybmw) this was a common theme.

[Charlie (Wessex)]

Originally Posted by tyranniux

That makes sense to me. Perhaps a good idea would be to have a look at the pressures recommended for the 3er xdrive saloon vs the g80 m3 xdrive saloon which I think has the PS4S as standard? This should give you some idea if the difference required. Wpuldnt surprise me if the michelin data is correct though.

There seems to be quite a wide range of recommended pressures between comfort and ECO, so I'm going to go for comfort settings, which are the low end. Fully loaded is closer to ECO than comfort.

So 2.7bar for a full ish car on non RFT, and maybe 2.6 later when car is just me. But hey, I'm not a tyre tech.....

[Charlie (Wessex)]

I'm confused......

I've looked at the RFT that came with the car. As per the picture, it states max inflation at 50psi. I also attach a photo of the sticker in the door, showing that fully loaded, I should set at 51psi, which of course is above the max pressure according to the tyre manufacturer.

Isn't this incredibly dangerous, or am I being stupid?

[UnluckySaxon]

Originally Posted by a.summers86

Common problem with the 255 wide turanzas. They wear unevenly even when run at correct pressures. Even running them lower or higher results in the same issue.

The middle of the tyre bellows slightly at higher speed meaning the contact patch is more on the middle.

Nothing you can do I’m afraid.

This is what happened with mine and the guy at ATS suggested that it was a tracking/alignment issue...

On the Michelin site, I cant seem to find how to get recommended pressures. It asks me to click a 'see results' tab but it doesnt exist!!

[Charlie (Wessex)]

Originally Posted by UnluckySaxon

This is what happened with mine and the guy at ATS suggested that it was a tracking/alignment issue...

On the Michelin site, I cant seem to find how to get recommended pressures. It asks me to click a 'see results' tab but it doesnt exist!!

When you enter all your details, there is a box saying "VIEW SIZE DETAILS" with a downward arrow. Click on that and it will expand.

Here's a link to my car/tyres... https://www.michelin.co.uk/auto/brow...owDetails=true