Running 18" wheels on 95 Eldorado, pressure question
Cadillac
 

Cadillac Forums | Help Us Help You | Advertise | Cadillac Parts | Cadillac News | Cadillac Classifieds / (Old System)

Cadillac Technical Archive | Cadillac Dealers | Cadillac Reviews | Cadillac Dealer Reviews | Cadillac Vendors

CadillacForums.com is the premier Cadillac Forum on the internet. Registered Users do not see the above ads.
+ Reply to Thread
Results 1 to 15 of 15
Like Tree2Likes
  • 4 Post By RippyPartsDept
Cadillac Seville / Cadillac Eldorado Forum Discussion, Running 18" wheels on 95 Eldorado, pressure question in Past Cadillac Vehicle Discussion; Put some 18's on my Eldorado, tire size 245/45/18. It had the stock 16's before. Ride seems a little different, ...
  1. #1
    eldoradogary is offline Cadillac Owners Fanatic
    Automobile(s): 1995 Cadillc Eldorado 2000 Cadillac Seville STS
    Join Date
    Jun 2012
    Age
    58
    Posts
    120

    Running 18" wheels on 95 Eldorado, pressure question

    Put some 18's on my Eldorado, tire size 245/45/18. It had the stock 16's before. Ride seems a little different, not quite as smooth. Anyone else running these size rims and tires? What air pressure have you found gives the best ride? 35 psi in all 4 now.

  2. Remove Advertisements
    CadillacForums.com
    Advertisements
     

  3. #2
    Submariner409's Avatar
    Submariner409 is offline If it won't run, chrome it
    Automobile(s): 2002.5 F55 STS/65500mi, 2004 Ford F150 SuperCab4x4
    Join Date
    Feb 2006
    Location
    MD Eastern Shore - Kent Island
    Age
    74
    Posts
    44,262

    Re: Running 18" wheels on 95 Eldorado, pressure question

    30 - 32 psi, cold. Always check/adjust tire pressures cold, never warm/hot.

  4. #3
    eldoradogary is offline Cadillac Owners Fanatic
    Automobile(s): 1995 Cadillc Eldorado 2000 Cadillac Seville STS
    Join Date
    Jun 2012
    Age
    58
    Posts
    120

    Re: Running 18" wheels on 95 Eldorado, pressure question

    Thanks, I'll give that a try.

  5. #4
    Submariner409's Avatar
    Submariner409 is offline If it won't run, chrome it
    Automobile(s): 2002.5 F55 STS/65500mi, 2004 Ford F150 SuperCab4x4
    Join Date
    Feb 2006
    Location
    MD Eastern Shore - Kent Island
    Age
    74
    Posts
    44,262

    Re: Running 18" wheels on 95 Eldorado, pressure question

    Something to remember about "ride" when changing to larger diameter wheels (from stock size): Your original tire outside diameter was about 27", so with 16" wheels you had about 5.5" of air/rubber between the wheel and pavement. Now, with 18" wheels you have reduced that "cushion" to 4.5". The car will ride "harder". (16" wheel, 27" OD tire = 11" of "tire". 11 / 2 = 5.5") (18" wheel, 27" OD tire = 9" of "tire". 9 / 2 = 4.5" cushion)

    Your new tires are the exact correct size for the car: If you change tire outside diameter by more than 0.25" you run into speedo calibration and powertrain management (shift point vs. power) problems.

  6. #5
    RippyPartsDept's Avatar
    RippyPartsDept is offline Hi, I'm Chris - Please Read My Signature
    Automobile(s): 1999 DeVille "Bianca" (white/blue, VIN-Y, 160k)
    Join Date
    Sep 2007
    Location
    Wilmington, NC
    Age
    34
    Posts
    13,967

    Re: Running 18" wheels on 95 Eldorado, pressure question

    you can use a tech2 to tell the car what size tires you are using so it calculates speed, mpg, etc correctly

    well i know you can do it for a '97 at least
    Chris Heath (RippyPartsDept) is an ASE Certified GM Parts Consultant at Rippy Automotive
    Rippy is a Cadillac, Hummer, Saturn & Saab dealership - family owned and operated in Wilmington, NC since 1946
    We offer all forum members discounts on parts and freight - e: parts@rippyautomotive.com ph: 800-RIPPY-22
    <-- insert standard boilerplate about posts not necessarily representing my employer, etc -->

  7. #6
    eldoradogary is offline Cadillac Owners Fanatic
    Automobile(s): 1995 Cadillc Eldorado 2000 Cadillac Seville STS
    Join Date
    Jun 2012
    Age
    58
    Posts
    120

    Re: Running 18" wheels on 95 Eldorado, pressure question

    Quote Originally Posted by Submariner409 View Post
    Something to remember about "ride" when changing to larger diameter wheels (from stock size): Your original tire outside diameter was about 27", so with 16" wheels you had about 5.5" of air/rubber between the wheel and pavement. Now, with 18" wheels you have reduced that "cushion" to 4.5". The car will ride "harder". (16" wheel, 27" OD tire = 11" of "tire". 11 / 2 = 5.5") (18" wheel, 27" OD tire = 9" of "tire". 9 / 2 = 4.5" cushion)

    Your new tires are the exact correct size for the car: If you change tire outside diameter by more than 0.25" you run into speedo calibration and powertrain management (shift point vs. power) problems.
    Thank you, yes that's what I figured less rubber betweeen wheel and pavement equals a little harder ride, still not bad though and worth it as it looks incredible.

  8. #7
    98eldo32v's Avatar
    98eldo32v is offline Cadillac Owners Connoisseur
    Automobile(s): 98 eldo/KD54 w/N37,T96,QA1,D55,DS3,U1Z. U3R next
    Join Date
    Apr 2010
    Posts
    1,868

    Re: Running 18" wheels on 95 Eldorado, pressure question

    pictures please.......

  9. #8
    Submariner409's Avatar
    Submariner409 is offline If it won't run, chrome it
    Automobile(s): 2002.5 F55 STS/65500mi, 2004 Ford F150 SuperCab4x4
    Join Date
    Feb 2006
    Location
    MD Eastern Shore - Kent Island
    Age
    74
    Posts
    44,262

    Re: Running 18" wheels on 95 Eldorado, pressure question

    Quote Originally Posted by eldoradogary View Post
    Thank you, yes that's what I figured less rubber betweeen wheel and pavement equals a little harder ride, still not bad though and worth it as it looks incredible.
    I'm seriously considering going to the Deville chrome spoke 18's with Z tires - for the lower sidewall handling aspect of tire/wheel sizing. My car is a F55, so there's no such thing as a "Cadillac ride" there, anyway.

  10. #9
    Submariner409's Avatar
    Submariner409 is offline If it won't run, chrome it
    Automobile(s): 2002.5 F55 STS/65500mi, 2004 Ford F150 SuperCab4x4
    Join Date
    Feb 2006
    Location
    MD Eastern Shore - Kent Island
    Age
    74
    Posts
    44,262

    Re: Running 18" wheels on 95 Eldorado, pressure question

    Quote Originally Posted by 98eldo32v View Post
    pictures please.......
    Somewhere near here is a thread with a picture of a Seville with Deville 18's on it. Looks great - just cover up the rear door.

    About 20 threads from here - 02 STS - 18" rims ? - All you gotta do is look outside the box ..................

  11. #10
    eldoradogary is offline Cadillac Owners Fanatic
    Automobile(s): 1995 Cadillc Eldorado 2000 Cadillac Seville STS
    Join Date
    Jun 2012
    Age
    58
    Posts
    120

    Re: Running 18" wheels on 95 Eldorado, pressure question

    badcad2.pngbadcad3.pngbadcad1.png
    Quote Originally Posted by 98eldo32v View Post
    pictures please.......
    Not the greatest pics, but you get the idea.

  12. #11
    eldoradogary is offline Cadillac Owners Fanatic
    Automobile(s): 1995 Cadillc Eldorado 2000 Cadillac Seville STS
    Join Date
    Jun 2012
    Age
    58
    Posts
    120

    Re: Running 18" wheels on 95 Eldorado, pressure question

    badmofo.pngHere's a better picture but I can't figure out how to post a bigger one.

  13. #12
    98eldo32v's Avatar
    98eldo32v is offline Cadillac Owners Connoisseur
    Automobile(s): 98 eldo/KD54 w/N37,T96,QA1,D55,DS3,U1Z. U3R next
    Join Date
    Apr 2010
    Posts
    1,868

    Re: Running 18" wheels on 95 Eldorado, pressure question


  14. #13
    STS_Seville_Hunter is offline Cadillac Owners Enthusiast
    Automobile(s): 91 ETC, 91 STS, 98 Eldo Convertable, '93 Seville
    Join Date
    Sep 2008
    Location
    DHS/Palm Springs, CA
    Age
    27
    Posts
    632

    Re: Running 18" wheels on 95 Eldorado, pressure question

    Hard to find colour, one of my favorties, does it have the matching purpleish interior?

  15. #14
    eldoradogary is offline Cadillac Owners Fanatic
    Automobile(s): 1995 Cadillc Eldorado 2000 Cadillac Seville STS
    Join Date
    Jun 2012
    Age
    58
    Posts
    120

    Re: Running 18" wheels on 95 Eldorado, pressure question

    Quote Originally Posted by STS_Seville_Hunter View Post
    Hard to find colour, one of my favorties, does it have the matching purpleish interior?
    \

    Yes, it has the matching purpleish leather. I've never seen another in this color, mocha pearl, almost looks lavender in certain light.

  16. #15
    stoveguyy is online now Cadillac Owners Connoisseur
    Automobile(s): 96 STS, 140k
    Join Date
    Aug 2007
    Location
    mpls mn
    Posts
    2,484

    Re: Running 18" wheels on 95 Eldorado, pressure question

    Pressure is one thing but brand/speed rating is another. Pretty sure most 45 series tires are max performance. The sidewall construction is a big variable.

Quick Reply Quick Reply

Register Now

Please enter the name by which you would like to log-in and be known on this site.
If you do not want to register, fill this field only and the name will be used as user name for your post.

Please enter a password for your user account. Note that passwords are case-sensitive.

Please enter a valid email address for yourself.

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Bookmarks

Cadillac Posting Rules

  • You may post new threads
  • You may post replies
  • You may not post attachments
  • You may not edit your posts
Read about Lincoln | Buick | Kia Forte Forum
Need products for your Cadillac? Check out your options at the links below:

custom floor mats | Cadillac Chrome and Black Chrome Wheels | window tinting