Tire pressure for square setup?

BB_cuda · 04-12-2018, 03:15 PM

2011 335D m-sport. Converting from OEM sport stagger setup (18x8 F and 18x18.5 R: 225/40/18 F and 255/35/18 R)

to Apex SM-10 18x9 all around and wearing 255/35/18 Mich Pilot Sport 4S all around.

The B pillar shows 35 psi F and 41 psi R. I'm thinking to go to same pressure all around. Suspension is not factory now. M3 control arms front and rear including the lower camber links. M3 sway bars (sedan diameter), ground control coil overs. Adjustable toe links on rear. Camber plates on front. Koni yellows (single adjustable). The camber is -1.5° at all 4 corners. My current setup shows even wear across the tread.

I was thinking 38 psi but looking for suggestions. My diesel's weight distribution is approx 52%F/48%R. I have been told that having wider tires on the front is going to take me from over steer toward oversteer direction.

Perhaps this post belongs over in suspension/chassis section but I thought I'd try here first.

dsjr2006 · 04-12-2018, 03:30 PM

I'd think you'd just have less understeer with equal size tires all around.

Tire pressure is more about weight distribution than tire size, the point is to keep the proper tire shape and maintain the correct contact patch. Your vehicle weight distribution changes when there are passengers inside (including you) and I assume that's why they put more in the rear because of passengers and cargo.

I personally would adjust the tires based on BMW recommendations so increase only for high-speed and adjust for track usage, outside of that use what's on the door placard.

boosthead · 04-12-2018, 04:35 PM

Even with a square setup, BMW specs higher pressure in the rear. I run 255/40-17 tires front and rear. I started at the BMW recommended tire pressure and adjusted based on feel and tire wear. I think I'm still running the same difference in PSI front to rear, just up 2psi over both recommended values.

AoS810 · 04-12-2018, 06:32 PM

I was running 35 up front and 38 in the rear when I had Continental DW on stock wheels. America's Tires said my rear center was wearing a lot faster compared to the sides (it really was) and my fronts were perfect. Leads me to believe my rears were over inflated. I'm now running 35 all around on my square setup.

BB_cuda · 04-12-2018, 07:56 PM

Thanks to all. I went with initial setting of 38 all around but i’m apt to drop down to 35 all around. I will watch wear carefully.

derkenblosh · 11-25-2018, 10:29 PM

335D stage2
Bilstein b12 prokit (4-6mm lower than M-Sport)
M3 front control arms w/ M3 factory allignment in front
335 factory allignment rear
17x9 arc8's with 245 40's square PSS

I ran 32PSI in the rear, 28 front, rotate every 5kmi (I'm REALLY rough on tires, my route to work is....fun)

I'm at 16kmi on the tires and at 2/32 on the inside edges of all four tires, I think I'm going to be dropping to 30PSI on the rears on the next set, hoping to get a little more life out of them. Weight bias is even more forward on the car and the def tanks are gone.

dsjr2006 · 11-26-2018, 05:03 PM

Quote:

Originally Posted by derkenblosh

I'm at 16kmi on the tires and at 2/32 on the inside edges of all four tires, I think I'm going to be dropping to 30PSI on the rears on the next set, hoping to get a little more life out of them. Weight bias is even more forward on the car and the def tanks are gone.

That's not a tire pressure issue, that's a toe issue.

nsjames · 11-27-2018, 11:21 PM

chalk test them on some smooth pavement.

adjust until chalk wears evenly.

derkenblosh · 02-04-2019, 01:44 AM

Quote:

Originally Posted by FCobra94

That's not a tire pressure issue, that's a toe issue.

Zero toe, noticed one side / inside tread... Wore a little sooner. I think it's time for bushings in the rear (getting sloppy)

Chalked em, 34psi is the sweet spot for me in the rears For PSS.

Putting a set of 255 NT05's on next week, we'll see how they fair to the abuse

02-04-2019, 10:50 AM

Quote:

Originally Posted by derkenblosh

Quote:

Originally Posted by FCobra94

That's not a tire pressure issue, that's a toe issue.

Zero toe, noticed one side / inside tread... Wore a little sooner.

Yes, exactly...that inside wear is from too much toe out, which is exactly what's happening here. Go 1/16" or even an 1/8" in next time to reduce wear.

Biginboca · 02-04-2019, 12:41 PM

OP, I have very similar set up to you. I’m running 36psi on 18x9” ET30 Apex wheels and same tires PS4S 255/35r18. Camber -1.7 all around. M3 control arms all around. Lowered about 1/2” all around.

I’ve had this for about 6 weeks and seems to be wearing evenly.

drummr8 · 05-18-2020, 12:35 PM

Just in case anyone else bumps into this thread at some point... I am also running 255/35/18 on a square setup of rear Msport wheels (Style 193) that are 18x8.5 ET37 on my 2011 335xi. I am running a 5mm spacer in the front and 10mm spacer in the rear, tire pressure of 36psi based on recommendations here. So far so good, no abnormal wear - if I encounter a wear issue, I'll update my post here.

derkenblosh · 03-14-2023, 03:05 PM

Update for the internet archives.

I upgraded the rear subframe bushings, and that fixed my uneven tire wear issue... (Also stopped the car from pointing & darting on the freeway when accelerating on concrete with rain grooves)

I Measured and verified the rear toe is ever so slightly toe-out.

Current tires PS4S, 245/40 17
F32.5psi
R34psi

fleetfoot · 10-01-2023, 09:07 PM

I was running 32/36 front/rear with Apex EC-7 18x9" and ExtremeContact DSW06+ tires. I noticed the front sidewalls were rolling over at full steering lock in my driveway leading to visible scuffing. I guess the allseason sidewalls are really soft compared to PS4S I had previously. I upped pressure to 35psi all around and that helped some, but didn't totally solve the problem. I might try 36psi, but not sure I'll go much higher than that.

Mrmigs2011 · 10-04-2023, 07:19 AM

Usually I run 32 all around which is perfect if you can get the heat into them and the pressure expansion.

Last night with some pressure testing as 32 felt like the fronts were a tad too soft, based off the wear im seeing on the tyres 36 is a much better happier medium for e92 chassis.

If I'm being pro picky then based off the wear on my tire markings I would say on square..

37 driver side, 36 pass, 35 rear both.

This should balance out any wear as believe with driver only the extra weight of the driver is being loaded on the corresponding wheel!

At least how it looks on mine.

Any more experience about?

04-12-2018, 03:15 PM	#1
BB_cuda Brigadier General 776 Rep 3,559 Posts Drives: 2011 335D Msport, 2013 X5D Join Date: Nov 2011 Location: Clear Lake, Texas iTrader: (0)	Tire pressure for square setup? 2011 335D m-sport. Converting from OEM sport stagger setup (18x8 F and 18x18.5 R: 225/40/18 F and 255/35/18 R) to Apex SM-10 18x9 all around and wearing 255/35/18 Mich Pilot Sport 4S all around. The B pillar shows 35 psi F and 41 psi R. I'm thinking to go to same pressure all around. Suspension is not factory now. M3 control arms front and rear including the lower camber links. M3 sway bars (sedan diameter), ground control coil overs. Adjustable toe links on rear. Camber plates on front. Koni yellows (single adjustable). The camber is -1.5° at all 4 corners. My current setup shows even wear across the tread. I was thinking 38 psi but looking for suggestions. My diesel's weight distribution is approx 52%F/48%R. I have been told that having wider tires on the front is going to take me from over steer toward oversteer direction. Perhaps this post belongs over in suspension/chassis section but I thought I'd try here first. Last edited by BB_cuda; 04-12-2018 at 03:50 PM..
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04-12-2018, 03:30 PM	#2
dsjr2006 Captain 159 Rep 848 Posts Drives: '01 E39 540iA, '09 E90 M3 Join Date: May 2013 Location: Metro Detroit iTrader: (1) Garage List 2010 BMW 335i [0.00] 2001 BMW 540i [0.00]	I'd think you'd just have less understeer with equal size tires all around. Tire pressure is more about weight distribution than tire size, the point is to keep the proper tire shape and maintain the correct contact patch. Your vehicle weight distribution changes when there are passengers inside (including you) and I assume that's why they put more in the rear because of passengers and cargo. I personally would adjust the tires based on BMW recommendations so increase only for high-speed and adjust for track usage, outside of that use what's on the door placard. __________________ E90 M3 DCT LCI \| E90 LCI N54 M-Sport(retired) \| E90 Technical Docs download: http://j.mp/bmwe90docs *good read, very detailed.
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04-12-2018, 04:35 PM	#3
boosthead Private First Class 40 Rep 124 Posts Drives: 2009 328ix Join Date: Jan 2017 Location: VA iTrader: (0)	Even with a square setup, BMW specs higher pressure in the rear. I run 255/40-17 tires front and rear. I started at the BMW recommended tire pressure and adjusted based on feel and tire wear. I think I'm still running the same difference in PSI front to rear, just up 2psi over both recommended values.
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04-12-2018, 06:32 PM	#4
AoS810 Lieutenant 98 Rep 416 Posts Drives: 2008 E90 N51, 2011 E91 N52 Join Date: Oct 2009 Location: Los Angeles, CA iTrader: (6)	I was running 35 up front and 38 in the rear when I had Continental DW on stock wheels. America's Tires said my rear center was wearing a lot faster compared to the sides (it really was) and my fronts were perfect. Leads me to believe my rears were over inflated. I'm now running 35 all around on my square setup.
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04-12-2018, 07:56 PM	#5
BB_cuda Brigadier General 776 Rep 3,559 Posts Drives: 2011 335D Msport, 2013 X5D Join Date: Nov 2011 Location: Clear Lake, Texas iTrader: (0)	Thanks to all. I went with initial setting of 38 all around but i’m apt to drop down to 35 all around. I will watch wear carefully.
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11-25-2018, 10:29 PM	#6
derkenblosh Private 9 Rep 56 Posts Drives: White 335D & White Suburban Join Date: Sep 2015 Location: Las Vegas, NV iTrader: (0)	335D stage2 Bilstein b12 prokit (4-6mm lower than M-Sport) M3 front control arms w/ M3 factory allignment in front 335 factory allignment rear 17x9 arc8's with 245 40's square PSS I ran 32PSI in the rear, 28 front, rotate every 5kmi (I'm REALLY rough on tires, my route to work is....fun) I'm at 16kmi on the tires and at 2/32 on the inside edges of all four tires, I think I'm going to be dropping to 30PSI on the rears on the next set, hoping to get a little more life out of them. Weight bias is even more forward on the car and the def tanks are gone.
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11-27-2018, 11:21 PM	#8
nsjames Brigadier General 2461 Rep 4,328 Posts Drives: 08 328xi Touring Join Date: May 2017 Location: ohio iTrader: (0)	chalk test them on some smooth pavement. adjust until chalk wears evenly.
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02-04-2019, 12:41 PM	#11
Biginboca Colonel 3787 Rep 2,738 Posts Drives: 2009 E92 328i 6MT Join Date: Jun 2017 Location: Boynton Beach, FL... USA iTrader: (3)	OP, I have very similar set up to you. I’m running 36psi on 18x9” ET30 Apex wheels and same tires PS4S 255/35r18. Camber -1.7 all around. M3 control arms all around. Lowered about 1/2” all around. I’ve had this for about 6 weeks and seems to be wearing evenly.
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05-18-2020, 12:35 PM	#12
drummr8 6MT FTMFW 69 Rep 233 Posts Drives: 11 E90 335xi E91 6MT 12 X5 35i Join Date: Feb 2019 Location: SC iTrader: (0) Garage List 2005 330ci Vert ZHP [0.00] 2011 335xi Sedan M- ... [0.00] 2011 328xi Wagon M- ... [0.00] 2012 X5 35i M-Sport [0.00]	Just in case anyone else bumps into this thread at some point... I am also running 255/35/18 on a square setup of rear Msport wheels (Style 193) that are 18x8.5 ET37 on my 2011 335xi. I am running a 5mm spacer in the front and 10mm spacer in the rear, tire pressure of 36psi based on recommendations here. So far so good, no abnormal wear - if I encounter a wear issue, I'll update my post here. __________________ 2011 LMB E90 335xi 6MT: Wagner EvoII FMIC, Catless DP, PE Mod, Cobb CP, BMC Filter, ST Coilovers, Strongflex TSB's, Whiteline RSFB Inserts, CDV Delete, Hawk Talon Rotors & PC Pads 2011 SGM E91 328xi 6MT: 3-Stage Intake Manifold, ST coilovers, 335i brake kit, drilled/slotted rotors, CDV Delete, Charcoal Filter Delete
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03-14-2023, 03:05 PM	#13
derkenblosh Private 9 Rep 56 Posts Drives: White 335D & White Suburban Join Date: Sep 2015 Location: Las Vegas, NV iTrader: (0)	Update for the internet archives. I upgraded the rear subframe bushings, and that fixed my uneven tire wear issue... (Also stopped the car from pointing & darting on the freeway when accelerating on concrete with rain grooves) I Measured and verified the rear toe is ever so slightly toe-out. Current tires PS4S, 245/40 17 F32.5psi R34psi
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10-01-2023, 09:07 PM	#14
fleetfoot Second Lieutenant 198 Rep 289 Posts Drives: 2017 M2, 2013 E92 328i Join Date: Apr 2013 Location: Atlanta,GA iTrader: (1)	I was running 32/36 front/rear with Apex EC-7 18x9" and ExtremeContact DSW06+ tires. I noticed the front sidewalls were rolling over at full steering lock in my driveway leading to visible scuffing. I guess the allseason sidewalls are really soft compared to PS4S I had previously. I upped pressure to 35psi all around and that helped some, but didn't totally solve the problem. I might try 36psi, but not sure I'll go much higher than that. __________________ 2017 F87 M2: MGM, 6MT, AA Tune, Eibach Pro-Kit, Fabspeed Catted Downpipe, Evolution Racewerks FMIC+Chargepipe, Autosolutions SSK, CDV Delete, Vorshlag Plates, PFC-08 pads, Apex EC-7 18x9.5" 2013 E92 328i M-Sport: BSM, 6MT, 3IM+AA Tune, BMW PE, M3 control arms, Bilstein B12 Pro-Kit, BMW SSK, CDV Delete, Apex EC-7 18x9"
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10-04-2023, 07:19 AM	#15
Mrmigs2011 Private 26 Rep 67 Posts Drives: 2006 E92 335i Join Date: Aug 2023 Location: Barton Upon Humber iTrader: (0)	Usually I run 32 all around which is perfect if you can get the heat into them and the pressure expansion. Last night with some pressure testing as 32 felt like the fronts were a tad too soft, based off the wear im seeing on the tyres 36 is a much better happier medium for e92 chassis. If I'm being pro picky then based off the wear on my tire markings I would say on square.. 37 driver side, 36 pass, 35 rear both. This should balance out any wear as believe with driver only the extra weight of the driver is being loaded on the corresponding wheel! At least how it looks on mine. Any more experience about?
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