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
      01-09-2017, 07:45 PM   #1
coh661
Banned
United_States
190
Rep
453
Posts

Drives: 2007 Z4M Coupe
Join Date: Dec 2015
Location: WY

iTrader: (4)

Garage List
2007 Z4 M COUPE  [8.00]
Question on Tire Profile & Overall Diameter (18" vs 19")

So i recently made the switch from my OEM 18's to some HRE FF01 19's. In doing so i went with the following tires (MPSS's 225/35/19 front & 265/30/19 Rears). I chose slightly narrower sizes due to PSS section width running wider than other brands and the aggressive front offset of the FF01's. (My current set up is OEM 18's with MPSS 225/45/18 front and 255/40/18 rears)

For the sake of discussion lets just talk about the rears. Per the tire calculator and Michelin specs, the overall tire diameter of my 19's is about 17 mm in diameter smaller than the stock 18's. This difference is noticeable to me as my 19's look slightly smaller within the wheel arches than stock (enough to bother me).

My question is, should I have gone with a 35 profile instead of a 30 profile? This would have resulted in a overall diameter that is closer to stock (albeit 7 mm larger than stock). Both profiles fall within the 3% rule from stock so i think both are ok but is there a reason why 35 profile wouldn't make more sense? Better ride, better speedo calibration, maintains closer to stock ride height and just a slightly larger OD......Your expert advice is welcomed!

Last edited by coh661; 01-10-2017 at 08:49 AM..
Appreciate 0
      02-04-2017, 11:30 AM   #2
coh661
Banned
United_States
190
Rep
453
Posts

Drives: 2007 Z4M Coupe
Join Date: Dec 2015
Location: WY

iTrader: (4)

Garage List
2007 Z4 M COUPE  [8.00]
Bump, anyone?
Appreciate 0
      02-04-2017, 01:02 PM   #3
XMetal
Colonel
XMetal's Avatar
United_States
1097
Rep
2,846
Posts

Drives: Anything
Join Date: Apr 2010
Location: SoCal

iTrader: (0)

Garage List
2008 Z4M Coupe  [10.00]
2018 Audi S3  [0.00]
2004 X5  [8.50]
Not expert advice...But

IMHO, you should definitely go with the 35 profile for all the reasons that you've mentioned. The engine would be more relax on highway cruising. The taller 35 profile would also stretch less over the 10" wide wheels. But you may also have to up the front profile as well to keep the front/rear ratio balanced.
Appreciate 0
      02-04-2017, 01:07 PM   #4
coh661
Banned
United_States
190
Rep
453
Posts

Drives: 2007 Z4M Coupe
Join Date: Dec 2015
Location: WY

iTrader: (4)

Garage List
2007 Z4 M COUPE  [8.00]
Quote:
Originally Posted by XMetal View Post
Not expert advice...But

IMHO, you should definitely go with the 35 profile for all the reasons that you've mentioned. The engine would be more relax on highway cruising. The taller 35 profile would also stretch less over the 10" wide wheels. But you may also have to up the front profile as well to keep the front/rear ratio balanced.
For sure. If I bump the rear profile up, I'll bump the fronts too. Just wanted to see if anyone with 19's has run those larger profiles with narrower tires like I want to do. My tires just look too thin currently and I can't get over the smaller OD and how they look in the wells. I'm just worried that the larger profiles will rub
Appreciate 0
      02-04-2017, 01:23 PM   #5
XMetal
Colonel
XMetal's Avatar
United_States
1097
Rep
2,846
Posts

Drives: Anything
Join Date: Apr 2010
Location: SoCal

iTrader: (0)

Garage List
2008 Z4M Coupe  [10.00]
2018 Audi S3  [0.00]
2004 X5  [8.50]
That is a concern if you are already on an aggressive setup. But if that tiny 5% profile increase cause you to rub, then going over a large bumps/wide steering angles should also cause rubbing right now. Do you have any rubbing issues now? My quick and dirty method for checking for rub or rooms available is to drive 1 wheel onto a ramp (or driveway/sidewalk) and check the opposite corner for wheel/fender clearance.
Appreciate 0
      02-04-2017, 02:45 PM   #6
coh661
Banned
United_States
190
Rep
453
Posts

Drives: 2007 Z4M Coupe
Join Date: Dec 2015
Location: WY

iTrader: (4)

Garage List
2007 Z4 M COUPE  [8.00]
Quote:
Originally Posted by XMetal View Post
That is a concern if you are already on an aggressive setup. But if that tiny 5% profile increase cause you to rub, then going over a large bumps/wide steering angles should also cause rubbing right now. Do you have any rubbing issues now? My quick and dirty method for checking for rub or rooms available is to drive 1 wheel onto a ramp (or driveway/sidewalk) and check the opposite corner for wheel/fender clearance.
I just finished my H&R coilover install but due to the weather I haven't pulled it out of the garage yet. I'll test it like you say when the weather clears up. Maybe I'll run these tires for a bit and once comfortable they won't rub I'll step up to the larger profiles.
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 07:44 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