ZPOST
BMW Garage BMW Meets Register Search Today's Posts Mark Forums Read


Go Back   ZPOST > BMW Z4 Technical Talk > Wheels and Tires
  TireRack

SUPPORT ZPOST BY DOING YOUR TIRERACK SHOPPING FROM THIS BANNER, THANKS!
Post Reply
 
Thread Tools Search this Thread
      03-14-2008, 02:46 PM   #1
MakoBimmer1
Booyakasha!
MakoBimmer1's Avatar
United_States
40
Rep
413
Posts

Drives: '13 Mini Cooper S Coupe'
Join Date: Sep 2006
Location: Kihei, HI

iTrader: (0)

Garage List
Unhappy How to determine correct tire pressures?!?!?

Since replacing my OEM M wheels/tires with aftermarket rims/tires I am unsure of the correct pressures to run. Ive tried 30psi as recommended by BMW for the stock setup, but does not feel right with the larger wheels/smaller tires setup.

Is there an equation to determine correct pressures???

The sidewall on the GoodYear Eagle F1 GS D3s recommends pressures under 50psi but of course Im not going to go near that #. Im tired of testing pressures every other day!!! Thanks to all with real information!

--Chad
__________________
'08 M Coupe--AW/IR--SOLD!--My M Coupe Obsession
'13 Mini Cooper S Coupe - My Maui Mobile
'13 Mini Cooper S Paceman- My Maui 'Stuff Hauler'
Appreciate 0
      03-14-2008, 03:37 PM   #2
Hawkeye
Brigadier General
Hawkeye's Avatar
No_Country
2070
Rep
4,365
Posts

Drives: '07 Z4 Coupe, '21 X3, '16 GMC
Join Date: Aug 2007
Location: Iowa

iTrader: (0)

Garage List
I usually go about 2-3 psi under the recommended max pressure of the tire. I have never had a blowout or any other pressure related problem.
__________________
2007 Z4 3.0si Coupe • 6 MT • Black Saphire Metallic • PP • SP
2016 GMC Sierra SLT Z71 Premium Plus 4x4
2017 Harley StreetGlide • Denim Black • V&H Tune
2021 BMW x30i • Phytonic Blue Metallic • Fully loaded
Appreciate 0
      03-14-2008, 03:49 PM   #3
vachss
Captain
54
Rep
815
Posts

Drives: Z4 Coupe
Join Date: Jan 2008
Location: Ventura County, CA

iTrader: (1)

Quote:
Originally Posted by Hawkeye View Post
I usually go about 2-3 psi under the recommended max pressure of the tire. I have never had a blowout or any other pressure related problem.
I like high pressures for autocrossing as it prevents rolling of the sidewall, but driving that way all the time don't you get exaggerated wear in the center of the tread?
Appreciate 0
      03-14-2008, 04:59 PM   #4
BlackSapphireZ
Major
97
Rep
1,191
Posts

Drives: 22 GLE 53 Coupe
Join Date: Aug 2007
Location: Ladson, SC

iTrader: (0)

Quote:
Originally Posted by Hawkeye View Post
I usually go about 2-3 psi under the recommended max pressure of the tire. I have never had a blowout or any other pressure related problem.
you do know by the time tire warms up, it will reach or exceed max pressure. 40psi is not recommended by anyone

I go 2psi above Manufacturer's recommendation COLD PSI btw.
__________________
2022 GLE 53 Coupe
Appreciate 0
      03-16-2008, 04:46 AM   #5
BimmerZealot
Major
61
Rep
1,210
Posts

Drives: 2019 BMW X3 xDrive30i
Join Date: May 2007
Location: San Diego, California

iTrader: (2)

30 rears, 33 front for me. Or as close as I can get, and as cold as i can manage. Its mostly personal preference, ride quality, handling, etc. Obviously you dont want to under inflate
Appreciate 0
      03-16-2008, 01:02 PM   #6
Dammmittt
My favorite sign.
Dammmittt's Avatar
South Korea
167
Rep
4,333
Posts

Drives: 2007 M Coupe
Join Date: Dec 2006
Location: Der Autobahnen

iTrader: (0)

It depends on a ton of factors...start with the recommended tire pressure for stock tires, and slowly increase it...If I were you I wouldn't go above 35 psi for daily driving...what are the complete tire specs?
__________________


07 ///M Coupe (Premium Package) Black Saphire Ext. Imola Red Int.

Best Website EVER!
Appreciate 0
      03-16-2008, 02:51 PM   #7
RussRamz
M Slut
RussRamz's Avatar
United_States
18
Rep
564
Posts

Drives: 2011 M3 Coupe Mineral White
Join Date: Sep 2007
Location: Adenau, GE via 3 years in dreadful El Paso, TX

iTrader: (0)

I don't know about Goodyear, but you may want to research their site and see if you can find recommended tire pressures cold/hot. Michelin has recommended pressures for PS Cup tires at 25/27 psi cold front/rear with a target temp of 32/34 front/rear when hot and to change pressures in 2 psi increments when making adjustments. Having a tyre pyrometer also helps, but that is likely going overboard in your situation.

Check out Goodyear and see what they recommend. Probably a good place to start.
__________________
You have to be 100% behind someone before you can stab them in the back.

David Brent
Appreciate 0
      03-17-2008, 06:00 PM   #8
Hawkeye
Brigadier General
Hawkeye's Avatar
No_Country
2070
Rep
4,365
Posts

Drives: '07 Z4 Coupe, '21 X3, '16 GMC
Join Date: Aug 2007
Location: Iowa

iTrader: (0)

Garage List
Quote:
Originally Posted by BlackSapphireZ View Post
you do know by the time tire warms up, it will reach or exceed max pressure. 40psi is not recommended by anyone

I go 2psi above Manufacturer's recommendation COLD PSI btw.
I usually do my tires when filling gas every now and then so I fill 2-3 psi under max when they are smokin hot
__________________
2007 Z4 3.0si Coupe • 6 MT • Black Saphire Metallic • PP • SP
2016 GMC Sierra SLT Z71 Premium Plus 4x4
2017 Harley StreetGlide • Denim Black • V&H Tune
2021 BMW x30i • Phytonic Blue Metallic • Fully loaded
Appreciate 0
      03-18-2008, 10:50 PM   #9
bosstones
Lieutenant Colonel
1144
Rep
1,532
Posts

Drives: o_0
Join Date: Mar 2008
Location: Suburbia

iTrader: (0)

With past cars, I've typically gone 31/33 or 33/34 front/rear. I'd say to start with what's listed on your car's plate (& in the manual) and go from there. Generally, I check the pressure cold. If I've been driving, I assume a 2 psi increase from heat so I subtract whatever the pressure happens to be by 2 psi to figure out the cold temp pressure.
Appreciate 0
      03-18-2008, 11:33 PM   #10
Hawkeye
Brigadier General
Hawkeye's Avatar
No_Country
2070
Rep
4,365
Posts

Drives: '07 Z4 Coupe, '21 X3, '16 GMC
Join Date: Aug 2007
Location: Iowa

iTrader: (0)

Garage List
Quote:
Originally Posted by bosstones View Post
With past cars, I've typically gone 31/33 or 33/34 front/rear. I'd say to start with what's listed on your car's plate (& in the manual) and go from there. Generally, I check the pressure cold. If I've been driving, I assume a 2 psi increase from heat so I subtract whatever the pressure happens to be by 2 psi to figure out the cold temp pressure.
What kind of tires though. I am running 48-50 psi on my fronts and rears.
__________________
2007 Z4 3.0si Coupe • 6 MT • Black Saphire Metallic • PP • SP
2016 GMC Sierra SLT Z71 Premium Plus 4x4
2017 Harley StreetGlide • Denim Black • V&H Tune
2021 BMW x30i • Phytonic Blue Metallic • Fully loaded
Appreciate 0
      03-19-2008, 12:34 AM   #11
Rick Hunter
Skull Squadron Leader
Rick Hunter's Avatar
304
Rep
2,031
Posts

Drives: '07 M Coupé & '16 435xi GCoupé
Join Date: May 2007
Location: The Emerald City

iTrader: (20)

I've heard the -10% rule (i.e. 10% less than max stated on tire). I haven't tried it out on my ride, though.

I am currently running 33psi (F) & 35psi (R) on my Generals.
__________________
Appreciate 0
      04-04-2008, 01:55 PM   #12
MakoBimmer1
Booyakasha!
MakoBimmer1's Avatar
United_States
40
Rep
413
Posts

Drives: '13 Mini Cooper S Coupe'
Join Date: Sep 2006
Location: Kihei, HI

iTrader: (0)

Garage List
I finally found that 34psi all around works best for me.... So much for some scientific mathmatical equation!
__________________
'08 M Coupe--AW/IR--SOLD!--My M Coupe Obsession
'13 Mini Cooper S Coupe - My Maui Mobile
'13 Mini Cooper S Paceman- My Maui 'Stuff Hauler'
Appreciate 0
      04-04-2008, 03:22 PM   #13
rosierobins2003
Rosie.....
United_States
61
Rep
1,104
Posts

Drives: 2016 Z4 2.8 Auto....
Join Date: May 2007
Location: Bay Area

iTrader: (0)

Garage List
2016 BMW  [0.00]
what about if you use nitrogen?
Appreciate 0
      04-04-2008, 04:20 PM   #14
Rick Hunter
Skull Squadron Leader
Rick Hunter's Avatar
304
Rep
2,031
Posts

Drives: '07 M Coupé & '16 435xi GCoupé
Join Date: May 2007
Location: The Emerald City

iTrader: (20)

Quote:
Originally Posted by rosierobins2003 View Post
what about if you use nitrogen?


Don't you remember your own thread? http://www.zpost.com/forums/showthread.php?t=77827
__________________
Appreciate 0
      04-04-2008, 05:20 PM   #15
rosierobins2003
Rosie.....
United_States
61
Rep
1,104
Posts

Drives: 2016 Z4 2.8 Auto....
Join Date: May 2007
Location: Bay Area

iTrader: (0)

Garage List
2016 BMW  [0.00]
Quote:
Originally Posted by Rick Hunter View Post


Don't you remember your own thread? http://www.zpost.com/forums/showthread.php?t=77827
hey, sometimes I just try to cause trouble, stir up the dust to see what you guys say. I KNOW that is hard to believe what with my innocence and all.

And I have no middle name, so make it trouble, rebel...whatever you like.

I just re-read that thread...and i was stirring up trouble then too......lol!!

Rosie
Appreciate 0
      04-04-2008, 09:02 PM   #16
Rick Hunter
Skull Squadron Leader
Rick Hunter's Avatar
304
Rep
2,031
Posts

Drives: '07 M Coupé & '16 435xi GCoupé
Join Date: May 2007
Location: The Emerald City

iTrader: (20)

That's why we love you!
__________________
Appreciate 0
      04-04-2008, 11:22 PM   #17
mister_roger
Private First Class
mister_roger's Avatar
13
Rep
136
Posts

Drives: 2003 Maldives Blue 2.5i
Join Date: May 2007
Location: Bellevue, WA

iTrader: (0)

Hmm... I've been wondering this tire pressure thing for a while myself. I've heard figures from 34/38, F/R for stock 18's (staggered), or 32/35, or 30/32 for track, blah blah.....

i would think that with low profile tires, you would want a higher PSI as to avoid denting your rims on potholes. Then again, you risk uneven tire wear if you over inflate.

I checked my tire pressure last week and it was at 30.5/34, F/R. Cornering had felt a bit soft so i inflated it back up to around 34/34 (non staggered setup). Stability seems to have improved, though potholes feel a little more jarring.
__________________
2003 Maldives Blue 2.5i -- 18" M6 wheels, 12mm rear spacer, ///MZ4 front bumper conversion, Eibach lowering springs, Koni shocks, Hotchkis F/R anti-roll bars, Helene Performance air filter.

Appreciate 0
      04-06-2008, 09:12 PM   #18
bosstones
Lieutenant Colonel
1144
Rep
1,532
Posts

Drives: o_0
Join Date: Mar 2008
Location: Suburbia

iTrader: (0)

Quote:
Originally Posted by Hawkeye View Post
What kind of tires though. I am running 48-50 psi on my fronts and rears.
Oi! What tires are you running? Is that for street driving?

I use the 31/33 psi for my snow tires (Michelin Alpin 2's) and, in the past, used 33/34 with Pilot Sports (PS1's)...although that was on my ZHP. I haven't had my coupe long enough to have the OE summer tires on for more than 2 weeks. I still got the snows on.

Quote:
Originally Posted by Rick Hunter View Post
I've heard the -10% rule (i.e. 10% less than max stated on tire). I haven't tried it out on my ride, though.

I am currently running 33psi (F) & 35psi (R) on my Generals.
General Exclaim UHP's? If so, how do you like them? I considered those but sidewall flex seemed to be a common complaint.
Appreciate 0
      04-07-2008, 02:16 AM   #19
Rick Hunter
Skull Squadron Leader
Rick Hunter's Avatar
304
Rep
2,031
Posts

Drives: '07 M Coupé & '16 435xi GCoupé
Join Date: May 2007
Location: The Emerald City

iTrader: (20)

Quote:
Originally Posted by bosstones View Post
General Exclaim UHP's? If so, how do you like them? I considered those but sidewall flex seemed to be a common complaint.
Well... when you get down to the 30 or 35 profiles, the sidewall flex "feels" about the same as OEM Contis with 40 or 45 profiles.

I'm pretty happy with them, and would probably do it again. I figured (at the time) that if they really did suck, then at least I didn't waste too much money (since they're dirt cheap). So far no complaints.
__________________
Appreciate 0
      04-07-2008, 01:03 PM   #20
M2audioman
Captain
United_States
197
Rep
837
Posts

Drives: 2018 M2
Join Date: Apr 2007
Location: Bay Area, CA

iTrader: (0)

I have 19's on my Z4MC and i'm running at 38F and 36R. Reduces understeer and seems well balanced overall.
Appreciate 0
      04-07-2008, 01:44 PM   #21
Hawkeye
Brigadier General
Hawkeye's Avatar
No_Country
2070
Rep
4,365
Posts

Drives: '07 Z4 Coupe, '21 X3, '16 GMC
Join Date: Aug 2007
Location: Iowa

iTrader: (0)

Garage List
Quote:
Originally Posted by bosstones View Post
Oi! What tires are you running? Is that for street driving?
Yes that is street driving... I have stock RFT tires. The Max is >50psi so I run a few under that usually. I guess I have always been taught to fill when the tires are warm and fill until it is close to the max psi.

Perhaps I'll drop it down another 5 psi (10%) and see how the ride is.
__________________
2007 Z4 3.0si Coupe • 6 MT • Black Saphire Metallic • PP • SP
2016 GMC Sierra SLT Z71 Premium Plus 4x4
2017 Harley StreetGlide • Denim Black • V&H Tune
2021 BMW x30i • Phytonic Blue Metallic • Fully loaded
Appreciate 0
      04-08-2008, 02:00 PM   #22
bosstones
Lieutenant Colonel
1144
Rep
1,532
Posts

Drives: o_0
Join Date: Mar 2008
Location: Suburbia

iTrader: (0)

Quote:
Originally Posted by Rick Hunter View Post
Well... when you get down to the 30 or 35 profiles, the sidewall flex "feels" about the same as OEM Contis with 40 or 45 profiles.

I'm pretty happy with them, and would probably do it again. I figured (at the time) that if they really did suck, then at least I didn't waste too much money (since they're dirt cheap). So far no complaints.
lol...I know what you mean. I'm looking at the Goodyear F1 Asymmetrics right now. Was going to reuse the front Pilot Sports from my ZHP since they got plenty of tread and the rubber is still somewhat soft and just buy new rears but....Tire Rack seemed to like the F1 A/S' more than the PS2! They seem promising even though there isn't a lot of reviews that I found on them.

Quote:
Originally Posted by Hawkeye View Post
Yes that is street driving... I have stock RFT tires. The Max is >50psi so I run a few under that usually. I guess I have always been taught to fill when the tires are warm and fill until it is close to the max psi.

Perhaps I'll drop it down another 5 psi (10%) and see how the ride is.
Ah-so, grasshoppa. I've always started with the OE recommendation and tweaked from there and always filled up cold. No biggie.
Appreciate 0
Post 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



All times are GMT -5. The time now is 10:42 AM.




zpost
Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
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