BMW M3 Forum (E90 E92)

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

Go Back   M3Post - BMW M3 Forum > E90/E92 M3 Technical Topics > Wheels + Tires Sponsored by The Tire Rack

Post Reply
Thread Tools Search this Thread
      12-14-2010, 01:49 AM   #1
Second Lieutenant
Drives: e92 ZCP
Join Date: Dec 2009
Location: USA

Posts: 208
iTrader: (0)

Help me choose a space saver spare tire size

I've decided to put together a spare tire kit for my e92 M3. I have the 19" wheel option and I am planning to run wider tires in the future (255/35-19 front and 275/35-19 rear on my ZCP wheels).

I used an online tire calculator program and based on the results, it appears that a 135/80-18 space saver spare tire most closely matches the rear tire size (planned: 275/35-19, current: 265/35-19). I'm thinking that using the rear tire diameter as the target size makes sense as it may reduce to difference in wheel rotations if the spare tire is on the rear, where the differential is. Is this logical and make sense?

The 145/70/-18 size looks close, too, but I haven't been able to source one in the ~ $100 range, so the 135/80-18 at around $100 is looking like a fair candidate. Thoughts?

Here is the calculation:

Specification Sidewall Radius Diameter Circumference Revs/Mile Difference
135/80-18 4.3in 13.3in 26.5in 83.3in 761 0.0%
245/35-19 3.4in 12.9in 25.8in 80.9in 783 -2.8%
265/35-19 3.7in 13.2in 26.3in 82.6in 767 -0.8%
255/35-19 3.5in 13.0in 26.0in 81.8in 775 -1.8%
275/35-19 3.8in 13.3in 26.6in 83.5in 759 0.3%

Last edited by sig5x; 12-14-2010 at 01:51 AM. Reason: format table
sig5x is offline  
Reply With Quote
      12-14-2010, 06:42 PM   #2
Drives: E92 M3
Join Date: Apr 2010
Location: USA

Posts: 704
iTrader: (0)

I found a Bridgestone T145/70-18 at Tire Rack. But, you won't find one for $100; think mine was around $250.
2011 Space Gray Coupe, DCT, ZCP, StopTech ST-60/ST-40 BBK.
elh0102 is offline  
Reply With Quote
Post Reply


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 05:38 AM.

Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.,,,,,,,,, logo and trademark are properties of BIMMERPOST