Tirerack
Use the following links to go directly to useful tirerack winter items: Tirerack Winter Tires. Gary's Winter Tire FAQ.
Using the links directly supports E90Post with tirerack sales commision!

  E90Post
 


TireRack

   PLEASE HELP SUPPORT E90POST BY DOING YOUR TIRERACK SHOPPING FROM THIS BANNER, THANKS!
 
BMW 3-Series (E90 E92) Forum > E90 / E92 / E93 3-series Technical Forums > Wheels and Tires Forum Sponsored by The Tire Rack > Tire Pressure with New Non-Run-flats PSS



Wheels and Tires forum Sponsored by The Tire Rack
Please help to directly support e90post by doing your tirerack shopping from the above link. For every sale made through the link, e90post gets sponsor support to keep the site alive. Disclaimer

Reply
 
Thread Tools Search this Thread
      04-18-2013, 02:20 PM   #1
Rmnelson12
Enlisted Member
1
Rep
31
Posts

 
Drives: 2009 BMW 335i Convertible E93
Join Date: Dec 2012
Location: United States

iTrader: (0)

Question Tire Pressure with New Non-Run-flats PSS

Just mounted and balanced some new Non Run Flat Michelin PSS to replace the stock Run Flats. The ride is great, I love em. But the tire pressure in the fronts are 45 and rears 48~.

NRFT or not, should the tire pressures still match does on the door frame and manual spec? OR do these tires require a different, higher tire pressure (PSI)?

Thanks
Appreciate 0
      04-19-2013, 09:01 PM   #2
ELiTeNeSs
Second Lieutenant
ELiTeNeSs's Avatar
2
Rep
224
Posts

 
Drives: 2008 BMW 335i
Join Date: Dec 2011
Location: Jacksonville, FL

iTrader: (1)

Discount tire advised me to keep it at the same pressure, runflats or not. Hope this helps.
Appreciate 0
      04-19-2013, 09:10 PM   #3
kaede
First Lieutenant
Canada
4
Rep
365
Posts

 
Drives: 2007 335i e90
Join Date: Mar 2013
Location: Vancouver BC

iTrader: (0)

Been reading about this too and most people say to start at somewhere Fronts and Rear at 35. Anyone knows? Also, does the PSI change if we're running 19" vs 18"? I will be acquiring 245/35/18 and 265/35/18 and frankly i have no idea what PSI to run at =(
__________________
94 NSX - Garage Queen
97 Integra Type R - Track Warrior
01 BMW E39 M5 (Sold), 2x 02 BMW E39 M5 (Sold & sold)
07 E90 335i 6MT - DD
2013 E63 AMG Wagon - Family Hauler
Appreciate 0
      04-19-2013, 09:29 PM   #4
flip4335
General Nuisance in a Private Conveyance
flip4335's Avatar
United_States
20
Rep
1,833
Posts

 
Drives: like it's rented
Join Date: Nov 2008
Location: behind the wheel

iTrader: (1)

Garage List
Quote:
Originally Posted by Rmnelson12 View Post
Just mounted and balanced some new Non Run Flat Michelin PSS to replace the stock Run Flats. The ride is great, I love em. But the tire pressure in the fronts are 45 and rears 48~.

NRFT or not, should the tire pressures still match does on the door frame and manual spec? OR do these tires require a different, higher tire pressure (PSI)?

Thanks
Whoa! Check the label on your driver side door.

Tire pressure should still be the same, RFT or non-RFT, doesn't matter.

With that said, I have Hankook Ventus 12 at 235/40/18F, 265/35/18R and I increased the pressure slightly, running 35psi front and 41psi rear for the occasional run up beyond 100mph. Yellow label on my door indicates 39psi front and 45psi rear for speeds up to and beyond 100mph for our rides, regardless of tire type.
__________________

BMWCCA Member # 414198 Slightly Modded|e90|SGM|6MT|LCI MSport Conversion|MTech|Premium|Cold|Sport|Tint|Blackline |219M|PSS|Quaife|Helix|AR Catted|Cobb
Quaife Review: http://www.e90post.com/forums/showthread.php?t=311570
Appreciate 0
      04-20-2013, 01:05 AM   #5
melloww22
Captain
melloww22's Avatar
10
Rep
615
Posts

 
Drives: 2011 335i E90
Join Date: Apr 2011
Location: San Diego

iTrader: (1)

The tire pressure needs to remain the same as posted on your driver side door entry labels... The weight of your front and back axle load did not change, you have the same engine and components summing up to the same weight as with RFTs or Non RFTs...(not counting wheels and tire difference) Remember if you up your rim size or change your tire specs your PSI will be different from your mark label

Tire PSI Equation
(Axle weight / 2) / Tire Capacity weight ) x Tire Max Pressure = Inflation Pressure.
Appreciate 0
      04-20-2013, 01:07 AM   #6
The Wildcard
Private
0
Rep
96
Posts

 
Drives: 335i
Join Date: Dec 2011
Location: California

iTrader: (0)

I just got these tires recently and my pressures are 38 psi front and 45 psi rear.
Appreciate 0
      04-20-2013, 01:12 AM   #7
melloww22
Captain
melloww22's Avatar
10
Rep
615
Posts

 
Drives: 2011 335i E90
Join Date: Apr 2011
Location: San Diego

iTrader: (1)

Quote:
Originally Posted by The Wildcard
I just got these tires recently and my pressures are 38 psi front and 45 psi rear.
This is right when running 18s with stock tire specs...
Appreciate 0
      04-20-2013, 08:23 AM   #8
reprod
Major
United_States
14
Rep
1,468
Posts

 
Drives: 435i (M-Sport)
Join Date: Apr 2008
Location: New York, NY

iTrader: (6)

Tire pressures should differ for 19inch rims I believe right? I've got a pair of PSS and SF-71s sitting at home right now waiting to be mounted. Just waiting for my new suspension components to come in.
__________________
'08 Sparkling Graph. E92 335xi (ZSP w/ 18s | Saddle Br. | Grey Poplar) (Returned)
'11 Space Grey E92 335xi M-Sport (KWv1 Coils | Saddle Brown | Bamboo) (Returned)
'14 Mineral Grey F32 335i M-Sport (DHP | LED Lights | Coral Red | Hexagonal Aluminum)
Appreciate 0
      04-20-2013, 01:06 PM   #9
BlueBimmer
Enthusiast
BlueBimmer's Avatar
United_States
4
Rep
272
Posts

 
Drives: 2009 335i Convertible
Join Date: Apr 2012
Location: PA

iTrader: (5)

Quote:
Originally Posted by melloww22 View Post
This is right when running 18s with stock tire specs...
weird - my door says 35 front, 42 rear - e93 N54 w/sport package
Appreciate 0
      04-20-2013, 03:57 PM   #10
DaFish
2008 335i E92, Almost full mods
Canada
23
Rep
1,077
Posts

 
Drives: 2008 335i E92, Procede V5
Join Date: Mar 2009
Location: Ontario, Canada

iTrader: (0)

Garage List
2008 335i Coupe  [3.00]
I just put in 38 all around on my PSSs.... is this incorrect? Should I run 45 in the rears?
__________________
2008 335i E92 Black, Procede Rev 2.5 (11-1 map), BMS DCI, AR Catless DPs, AMS FMIC, Procede PWM Meth, Forge DVs, CDV delete, 230s w/ 235/265 Michelin PSS, Dinan S3 susp w/ front/rear M3 arms (4), Wavetrac LSD, Subframe bushings, Dinan Rear Sway, Rogue toe arms, Stoptech Slotted rotors, Stoptech Street pads w/ steel lines
Appreciate 0
      04-21-2013, 01:56 PM   #11
redline2001
Lieutenant
13
Rep
476
Posts

 
Drives: AW 328i
Join Date: Oct 2010
Location: LI, NY

iTrader: (0)

Normal operating PSI for 18's are 32f, 35r .
Appreciate 0
      04-21-2013, 02:15 PM   #12
tres
Major
tres's Avatar
United_States
14
Rep
1,335
Posts

 
Drives: 2011 bmw 335is 6MT
Join Date: Apr 2009
Location: maryland

iTrader: (6)

i run 42f 38r which works great for me
__________________
Member #431510
oem perf cf spoiler and front lip/m3strut brace/m3 subframe bushings/wavetrac lsd/ TMS solid diff bushings/akg solid tension strut bushing/MR adjustable toe arms/MR adjustable upper link/full m3 suspension/ecs tuning ss brake lines/GC coilovers./CPE dci's,catless dp,intercooler,charge pipe bov/BMS OCC/tuningtechfs tuned/RB pcv valve/defiv diff lockdownkit
Appreciate 0
      04-21-2013, 04:29 PM   #13
stupordave
Private First Class
3
Rep
175
Posts

 
Drives: 2011 335is
Join Date: Sep 2011
Location: Golden, CO

iTrader: (1)

38psi all around on 19" Michelin PSS. Seems to be about right using the arrow indicators on the sidewalls.
__________________

2011 TiAg 335is, Dinan Stage 2 Susp, Dinan FMIC + Oil Cooler, COBB PTF Tune
Appreciate 0
      04-21-2013, 06:22 PM   #14
John_01
Colonel
John_01's Avatar
Australia
24
Rep
2,051
Posts

 
Drives: E90 325i, E82 135i
Join Date: Mar 2009
Location: Sydney, Australia

iTrader: (0)

I have no idea why people in the tire industry think the tire placard shows correct pressure for Non-RFT performance tires. My only guess it they don't want to be legally liable for their advice. The stock pressures are described according to the manufacturers preferred trade-off about ride comfort vs other considerations (!). Generally its not related to any mathematical calculation about weight loading, tirewear, handling or anything else.
Appreciate 0
      04-23-2013, 09:23 AM   #15
Gary@TireRack
Moderator
Gary@TireRack's Avatar
United_States
98
Rep
4,466
Posts

 
Drives: Formerly 1995 M3
Join Date: Oct 2006
Location: South Bend, IN, Tire Rack HQ

iTrader: (2)

In actuality, the vehicle manufacturer's recommended tire inflation pressures have a lot to do with load capacity, handling, and a variety of other factors the OEM must consider before putting their product into the hands of the general public.

Usually, vehicle manufacturers default to the worst case scenario of fully loaded and higher speed use, which puts a pretty high psi recommendation on the placard. Fortunately BMW takes hings further since they take the time and effort to tune and then recommend multiple inflation pressures based on how the vehicle is being loaded and driven. Depending what year your car was produced, the doorjamb placard may show only one inflation pressure recommendation, (intended to keep things simple) but BMW will show you alternate pressures for higher load, high speed driving in the vehicles owners manual and on some years on the tire placard itself.

To answer the OP's original question : The engineering rules that govern tire design and load capacity don't distinguish between runflat and conventional (non-runflat) tires. In a given tire size, a specific psi = ### load. Add to this what I've described above and as a starting point using the placard psi in your non-runflat replacement tires is the best place to start. You're free to adjust from there, but we strongly discourage considering going lower than what is recommended by the BMW.
__________________
Gary
Tire and Wheel Forum Moderator. Tire Rack Sales Rep
Gary@Tirerack.com
http://www.tirerack.com/a.jsp?a=AH8&url=index.jsp

Please refer to 'Gary' as your previous contact when you order online.
Appreciate 0
      04-23-2013, 11:56 AM   #16
Clammy
Second Lieutenant
2
Rep
237
Posts

 
Drives: 2008 328i
Join Date: May 2012
Location: Canada

iTrader: (1)

I have 18" staggered PSS on my 08 328i (w/ sport suspension), and go with the recommended pressures on the door sticker: 32 psi front, 41 psi rear. The ride is great, and the tires stay firmly glued to the road even when cornering hard. No complaints here.

Cheers!

Last edited by Clammy; 04-23-2013 at 12:16 PM.
Appreciate 0
      04-23-2013, 12:36 PM   #17
VMRWheels
BimmerPost Supporting Vendor
VMRWheels's Avatar
259
Rep
16,003
Posts


 
Drives: BMW
Join Date: Jun 2007
Location: Anaheim, CA

iTrader: (4)

Garage List
2014 BMW F22  [0.00]
2013 BMW F06  [0.00]
2013 BMW F30  [0.00]
Quote:
Originally Posted by flip4335 View Post
Whoa! Check the label on your driver side door.

Tire pressure should still be the same, RFT or non-RFT, doesn't matter.
+1

45/48 seems very high for the tire pressure, OP. Adjust accordingly.
__________________

VMR | Wheels - Mitch A. | p. 714-442-7916 extension 107 | e. Mitch@velocitymotoring.com | ** VMR Holiday Special! **
Appreciate 0
      04-24-2013, 02:17 AM   #18
John_01
Colonel
John_01's Avatar
Australia
24
Rep
2,051
Posts

 
Drives: E90 325i, E82 135i
Join Date: Mar 2009
Location: Sydney, Australia

iTrader: (0)

Quote:
Originally Posted by Gary@TireRack View Post
In actuality, the vehicle manufacturer's recommended tire inflation pressures have a lot to do with load capacity, handling, and a variety of other factors the OEM must consider before putting their product into the hands of the general public.
I'd agree there are a lot of factors. Not one pressure for everyone and every type of usage. However I don't know anyone who adjusts their tire pressure when going on highway trips or if they get 2 additional passengers.

A lot of people seem to choose the PSI figure for 2 people in their car, and then wonder why their tires don't wear evenly, why they get mushy handling from their high performance tires, and why they occasionally damage rims. Part of the problem is probably due to short trips in city traffic where they normally don't get the tires up to operating temperature. BMW's approach is different from most manufacturers and they give more detail, but I personally don't think its useful. Generally I think it leads to people underinflating their tires.

Last edited by John_01; 04-24-2013 at 02:30 AM.
Appreciate 0
      04-24-2013, 08:23 PM   #19
Pittsburger
Private First Class
Pittsburger's Avatar
1
Rep
112
Posts

 
Drives: 2010 328xi, 2006 330xi
Join Date: Aug 2011
Location: Long Island, NY

iTrader: (0)

Quote:
Originally Posted by melloww22 View Post
The tire pressure needs to remain the same as posted on your driver side door entry labels... The weight of your front and back axle load did not change, you have the same engine and components summing up to the same weight as with RFTs or Non RFTs...(not counting wheels and tire difference) Remember if you up your rim size or change your tire specs your PSI will be different from your mark label

Tire PSI Equation
(Axle weight / 2) / Tire Capacity weight ) x Tire Max Pressure = Inflation Pressure.
This equation is interesting, but obviously not right since BMW is known for 50/50 axle weight distribution and yet recommends a higher psi for rear axle. It's apparent that loading is missing as a variable in the equation.

I recommend experimenting. As long as you are around the recommended air pressure, probably at or up to 4 psi more, you'll prob have no problems. I like the firmer ride of adding +2 psi over recommended with conti dws nonRFT.
Appreciate 0
      04-24-2013, 08:37 PM   #20
Pittsburger
Private First Class
Pittsburger's Avatar
1
Rep
112
Posts

 
Drives: 2010 328xi, 2006 330xi
Join Date: Aug 2011
Location: Long Island, NY

iTrader: (0)

Quote:
Originally Posted by stupordave View Post
38psi all around on 19" Michelin PSS. Seems to be about right using the arrow indicators on the sidewalls.
I heard about the arrow indicators and not sure I believe it.
These arrows are designed to point out where the thread wear bars are.

Perhaps the only true test is to have the car under normal load run over some water or wetting fluid and run over paper such that it imprints the paper with the fluid. Getting the right "footprint" would indicate the "right" air pressure. Sounds like a pain to do, but if you really want to know, maybe it's worth the cost/time.
Appreciate 0
      04-24-2013, 09:32 PM   #21
Meeni
Gateropode
Meeni's Avatar
22
Rep
1,864
Posts

 
Drives: BMW 330i 06
Join Date: Apr 2012
Location: TN

iTrader: (0)

I run 34-38 on 17in PSS.

I've been running 29-36 (sticker advised) and it was bad (mushy turn in, mostly). I've also tried 33-33 all around, it was ok but it didn't felt tight and I could see traces or riding the sidewall after some hooliganism. I found that anything over 35 front was understeer prone, didn't like at all.

The arrow thing (michelinmans in PSS case) does work. At 34-38 the wear limit reaches exactly the top of michelinman's head.
Appreciate 0
      04-25-2013, 10:13 AM   #22
Gary@TireRack
Moderator
Gary@TireRack's Avatar
United_States
98
Rep
4,466
Posts

 
Drives: Formerly 1995 M3
Join Date: Oct 2006
Location: South Bend, IN, Tire Rack HQ

iTrader: (2)

Quote:
Originally Posted by Pittsburger View Post
These arrows are designed to point out where the thread wear bars are.
+1
__________________
Gary
Tire and Wheel Forum Moderator. Tire Rack Sales Rep
Gary@Tirerack.com
http://www.tirerack.com/a.jsp?a=AH8&url=index.jsp

Please refer to 'Gary' as your previous contact when you order online.
Appreciate 0
Reply

Bookmarks

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -5. The time now is 05:04 PM.




e90post
Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
1Addicts.com, BIMMERPOST.com, E90Post.com, F30Post.com, M3Post.com, ZPost.com, 5Post.com, 6Post.com, 7Post.com, XBimmers.com logo and trademark are properties of BIMMERPOST