Tire pressure in plus sized tires

scott135i · 09-27-2009, 09:52 AM

I have the 19" wheels with the sport package and I recently upgraded (with 50 miles on the car) to non-runflat tires. I switched to 235/35/19 in the front and 265/30/19 in the rear.

Does anyone know what the ideal tire pressure to use is? Should I use the recommended pressure that is on the sticker on the drivers door? I live in NY and winter is approaching if that makes any difference....

richard in NC · 09-27-2009, 10:44 AM

Quote:

Originally Posted by scott135i

I have the 19" wheels with the sport package and I recently upgraded (with 50 miles on the car) to non-runflat tires. I switched to 235/35/19 in the front and 265/30/19 in the rear.

Does anyone know what the ideal tire pressure to use is? Should I use the recommended pressure that is on the sticker on the drivers door? I live in NY and winter is approaching if that makes any difference....

I think the pressures on the door sticker are the best place to start but I've found non-RFT tires need more PSI than RFT's. Maybe start +2 or +4, mid to high 30s.

Z4 Beemer · 09-27-2009, 01:57 PM

From memory its ~33 psi front and ~41 psi rear for the 19's

teagueAMX · 09-27-2009, 06:05 PM

Quote:

Originally Posted by scott135i

I have the 19" wheels with the sport package and I recently upgraded (with 50 miles on the car) to non-runflat tires. I switched to 235/35/19 in the front and 265/30/19 in the rear.

Does anyone know what the ideal tire pressure to use is? Should I use the recommended pressure that is on the sticker on the drivers door? I live in NY and winter is approaching if that makes any difference....

I'm curious about your experience with the non-RFT compared to RFT tires. Please post or PM me after you've run them a month or so.

zEdP · 09-28-2009, 10:39 AM

Quote:

Originally Posted by teagueAMX

I'm curious about your experience with the non-RFT compared to RFT tires. Please post or PM me after you've run them a month or so.

Hi scott135i,

yes please share your experiences about these non-RFT alternatives...

EdP

jadatis · 09-29-2009, 09:19 AM

http://cid-a526e0eee092e6dc.skydrive...0tyre-pressure

In this map always take the newest form.
And there ar excamples placed too.

For your different tire-specifications front and rear , you have to fill in seperate forms for the front and rear axle, where you fill in at the form , only the data at the front axle-cels.

Hoping then that they did not use maximum tire pressure for heavy use at the rear. Otherwise the normal-advice-pressure calculating to the weights they used ,is incorrect.

You need from the car:
1 maximum axle- loads front and behind. Can be found on a metalisch plate under the motor hood or one of the door-styles.
2 Te maximum speed of the car . In the manual or can be estimated.
3. The advice pressures on the stikker somewher on the car or in the manual, that belong to the specific car. sometimes they are for a whole series of that type car.
4 : If the wheels are placed /-\ instead of so |-| and it is more then 2 degrees also the camber-angle. seldomly needed to be used

from the tires: example 195/65 R 15 XL 95 T
1 maximum load in KG,LBS or the Load-index ( 95 in example) found on the tire-side-wall.
2 Maximum speed of the tire. ( T in the example stands for max. 190km/h)
3 reference pressure. for this mostly the kind of tire is enaugh. ( XL in the example stands for Extra load also called reinforced, and has an reference pressure of 2.9 bar . Normal car tires 2.5 bar. but the form gives and accepts also PSI and kPa)

If you see at 250kPa on the side-wall then that is the reference pressure. Maximum pressure must be placed on the tire in some countries and is a less meaningfull term.
"at 250 kPa maximum pressure" is a notation that is not acording to the rules, so faults are made with this by the manufacturars. This makes the reference pressure a difficult to determine part in this.

09-27-2009, 09:52 AM	#1
scott135i Colonel 358 Rep 2,080 Posts Drives: 2020 X5 M50i Join Date: Feb 2009 Location: NYC Metro iTrader: (12)	Tire pressure in plus sized tires I have the 19" wheels with the sport package and I recently upgraded (with 50 miles on the car) to non-runflat tires. I switched to 235/35/19 in the front and 265/30/19 in the rear. Does anyone know what the ideal tire pressure to use is? Should I use the recommended pressure that is on the sticker on the drivers door? I live in NY and winter is approaching if that makes any difference....
	Appreciate 0 Tweet Quote

09-27-2009, 01:57 PM	#3
Z4 Beemer Colonel 85 Rep 2,353 Posts Drives: 2009 Z4 sDrive 23i Join Date: Oct 2005 Location: Glasgow, Scotland, UK iTrader: (0) Garage List 2006 E92 [0.00] 2004 Z4 2.2i [8.00]	From memory its ~33 psi front and ~41 psi rear for the 19's __________________ E89 Z4 sDrive 23i... for the more discerning driver
	Appreciate 0 Quote

09-29-2009, 09:19 AM	#6
jadatis Private 12 Rep 86 Posts Drives: No BMW Join Date: Sep 2009 Location: Holland Europe iTrader: (0)	Calculate it yourselves with my Excell-spreadsheet. http://cid-a526e0eee092e6dc.skydrive...0tyre-pressure In this map always take the newest form. And there ar excamples placed too. For your different tire-specifications front and rear , you have to fill in seperate forms for the front and rear axle, where you fill in at the form , only the data at the front axle-cels. Hoping then that they did not use maximum tire pressure for heavy use at the rear. Otherwise the normal-advice-pressure calculating to the weights they used ,is incorrect. You need from the car: 1 maximum axle- loads front and behind. Can be found on a metalisch plate under the motor hood or one of the door-styles. 2 Te maximum speed of the car . In the manual or can be estimated. 3. The advice pressures on the stikker somewher on the car or in the manual, that belong to the specific car. sometimes they are for a whole series of that type car. 4 : If the wheels are placed /-\ instead of so \|-\| and it is more then 2 degrees also the camber-angle. seldomly needed to be used from the tires: example 195/65 R 15 XL 95 T 1 maximum load in KG,LBS or the Load-index ( 95 in example) found on the tire-side-wall. 2 Maximum speed of the tire. ( T in the example stands for max. 190km/h) 3 reference pressure. for this mostly the kind of tire is enaugh. ( XL in the example stands for Extra load also called reinforced, and has an reference pressure of 2.9 bar . Normal car tires 2.5 bar. but the form gives and accepts also PSI and kPa) If you see at 250kPa on the side-wall then that is the reference pressure. Maximum pressure must be placed on the tire in some countries and is a less meaningfull term. "at 250 kPa maximum pressure" is a notation that is not acording to the rules, so faults are made with this by the manufacturars. This makes the reference pressure a difficult to determine part in this.
	Appreciate 0 Quote