Tyre pressures with no passengers

BIGTIME · 05-10-2010, 08:41 AM

I've got the standard 225 msport alloys with factory runflats. I was setting the pressures and noticed on the door card that they differ quite a lot depending on how many passengers I carry. The majority of the time I am on my own, surely I don't have to pump them up with the family in the car then let them down when I go to work on my own? I currently have them set when stone cold as 38psi at the front and 45 at the rear, does this seem ok? I am trying to minimilise outer tyre wear and chances of the alloys cracking.

creepy coupe · 05-10-2010, 08:59 AM

If you can live with 45 psi in the rears, all well and good, but inner edge wears is a problem on the rears.

BIGTIME · 05-10-2010, 09:01 AM

What do you think 45psi is too high for the rears?

creepy coupe · 05-10-2010, 09:03 AM

Quote:

Originally Posted by BIGTIME

What do you think 45psi is too high for the rears?

It's what's on the door card 3.0 bar, but I found 42 psi about as high as I could live with when I had RF's on mine.

HighlandPete · 05-10-2010, 10:22 AM

Quote:

Originally Posted by BIGTIME

I've got the standard 225 msport alloys with factory runflats. I was setting the pressures and noticed on the door card that they differ quite a lot depending on how many passengers I carry. The majority of the time I am on my own, surely I don't have to pump them up with the family in the car then let them down when I go to work on my own? I currently have them set when stone cold as 38psi at the front and 45 at the rear, does this seem ok? I am trying to minimilise outer tyre wear and chances of the alloys cracking.

Is your door shut placard showing two sets of recommended pressure settings, 4 adults max and 4+1 adults and luggage?

Sort of explains it, then we tune pressures for road feel and wear patterns. The main thing is not to run low pressures when loaded and/or driving long distances at high speed. For normal use low pressures usually end up contributing to odd wear and loss of the tyre shoulders.

HighlandPete

BIGTIME · 05-10-2010, 11:04 AM

Pete - The placard has pressure for 4 adults and luggage and i.e max and a min pressure if travelling on your own.

zltm089 · 05-10-2010, 12:58 PM

yeah 45 at the rears seems a lil bit high....are u on 18inch? I'm on 40 psi fronts and 42 psi rears...and i got 18s....standard bridgestone runflats...ride is very crashy...but i like it hard! ;-)

willhollin · 05-10-2010, 03:07 PM

Quote:

Originally Posted by zltm089

...but i like it hard! ;-)

So Sunny said.

F31-340i · 05-10-2010, 03:45 PM

When I had 225 & RFTs on my E91, I found the ride actually better when it was on the door settings (3.0 bar rear). It seemed to get harder with the tyres underinflated. Coupes maybe different of course.

BGM · 05-10-2010, 04:22 PM

i run mine on 0.2 bar over whatever it says on the placard..

need to check mine on the weekend tbh

toxicnerve · 05-10-2010, 05:22 PM

Quote:

Originally Posted by BGM

i run mine on 0.2 bar over whatever it says on the placard..

need to check mine on the weekend tbh

I think that's what mine are set to.

E92 with 19" 225s, fronts are 2.7 and rears are 3.2

I think that's pretty much smack in the middle of the minimum/maximum loading stated on the door sticker.

neilv · 05-10-2010, 06:40 PM

Yeah I've done the same, E90 with 18" 193...fronts are 2.6 and rears 3.1(i think)... has actually improved the ride and handling significantly...

mgarvey · 05-10-2010, 06:52 PM

Quote:

Originally Posted by neilv

Yeah I've done the same, E90 with 18" 193...fronts are 2.6 and rears 3.1(i think)... has actually improved the ride and handling significantly...

I do this too - 2.7 front 3.1 rear, so a little higher than the placard says for light loading.

05-10-2010, 08:41 AM	#1
BIGTIME Lieutenant 32 Rep 498 Posts Drives: E92 M3 DCT - Mineral White Join Date: Mar 2010 Location: North East iTrader: (0)	Tyre pressures with no passengers I've got the standard 225 msport alloys with factory runflats. I was setting the pressures and noticed on the door card that they differ quite a lot depending on how many passengers I carry. The majority of the time I am on my own, surely I don't have to pump them up with the family in the car then let them down when I go to work on my own? I currently have them set when stone cold as 38psi at the front and 45 at the rear, does this seem ok? I am trying to minimilise outer tyre wear and chances of the alloys cracking.
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05-10-2010, 08:59 AM	#2
creepy coupe Lieutenant General 1825 Rep 13,043 Posts Drives: BMW M340I G20 Join Date: Aug 2007 Location: UK iTrader: (2) Garage List 2015 BMW 435d [0.00] 2009 335i [0.00]	If you can live with 45 psi in the rears, all well and good, but inner edge wears is a problem on the rears.
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05-10-2010, 09:01 AM	#3
BIGTIME Lieutenant 32 Rep 498 Posts Drives: E92 M3 DCT - Mineral White Join Date: Mar 2010 Location: North East iTrader: (0)	What do you think 45psi is too high for the rears?
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05-10-2010, 11:04 AM	#6
BIGTIME Lieutenant 32 Rep 498 Posts Drives: E92 M3 DCT - Mineral White Join Date: Mar 2010 Location: North East iTrader: (0)	Pete - The placard has pressure for 4 adults and luggage and i.e max and a min pressure if travelling on your own.
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05-10-2010, 12:58 PM	#7
zltm089 Banned 259 Rep 7,686 Posts Drives: 335i SE Coupe Space Grey Join Date: Nov 2008 Location: LONDON iTrader: (0) Garage List 2006 BMW 335i [10.00]	yeah 45 at the rears seems a lil bit high....are u on 18inch? I'm on 40 psi fronts and 42 psi rears...and i got 18s....standard bridgestone runflats...ride is very crashy...but i like it hard! ;-)
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05-10-2010, 03:45 PM	#9
F31-340i Colonel 161 Rep 2,475 Posts Drives: BMW 340i Touring Join Date: Apr 2007 Location: ... iTrader: (1)	When I had 225 & RFTs on my E91, I found the ride actually better when it was on the door settings (3.0 bar rear). It seemed to get harder with the tyres underinflated. Coupes maybe different of course.
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05-10-2010, 04:22 PM	#10
BGM Colonel 62 Rep 2,398 Posts Drives: F20 M140i Join Date: Oct 2009 Location: Farnborough, UK iTrader: (0)	i run mine on 0.2 bar over whatever it says on the placard.. need to check mine on the weekend tbh
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05-10-2010, 06:40 PM	#12
neilv Enlisted Member 3 Rep 39 Posts Drives: 335d xDrive MSport Join Date: Mar 2010 Location: W. Sussex iTrader: (0)	Yeah I've done the same, E90 with 18" 193...fronts are 2.6 and rears 3.1(i think)... has actually improved the ride and handling significantly...
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