Jump to content

Custom Search

Welcome to the Ford Flex Forum

Sign In  Log in with Facebook

Create Account
Welcome to the Ford Flex Forum. Like most online communities, you must register to create topics or post in our community - but don't worry this is a simple free process that requires minimal information for you to signup. Be a part of the Ford Flex Forum by signing in or creating an account.
  • Start new topics and reply to others
  • Subscribe to topics and forums to get email updates
  • Get your own profile page and make new friends
  • Send personal messages to other members
  • Create a photo album and post photos. . .more!
Click here to create an account
Guest Message by DevFuse

Feel Faster?  We're Now on a Dedicated Server!

- - - - -

Replace all four?

  • Please log in to reply
2 replies to this topic



    New Flex Member

  • Ford Flex Members
  • 2 posts

Posted 14 June 2012 - 02:54 AM

I need a little help. My wife wrecked the drivers side rear tire on her 2010 Flex SEL AWD with 26K. When she went to the dealer to get it replaced she was told she had to replace all four tires because the difference in circumference in the one new tire would wreck the transfer case. Is this true? My first thought was B.S. when driving around any corner the outside tires are traveling at a different rate than the inside tires. In theory this would cause the same damage.

Thanks for the help.

#2 OFFLINE   Waldo


    New Flex Member

  • Ford Flex Members
  • 473 posts

Posted 14 June 2012 - 06:04 AM

It is not BS. In fact it's even printed in the owner's manual (page 271 in my 2009 book):

Major dissimilar tire sizes between the front and rear axles could cause the AWD system to stop functioning and default to front wheel drive or damage the AWD system.

It's not the inside to outside difference that's the problem, it's the front to rear. The question is how much is "major". I think you'll probably be ok with as much as a 5% difference, but 2-3% is usually the safe limit. So as long as you're replacing it with the same tire model and the other three have at least 6/32nds of tread left, I'd think you'll be ok.

The Flex doesn't have a transfer case, it has a RDU. Inside the RDU are clutches that control the power split front to rear, but they also account for the slip between the front and rear since there is no true center differential. So if your front and rear tires are different diameters, those clutches have to constantly slip to compensate, that can overheat them and eventually wear them out.

Edited by Waldo, 14 June 2012 - 06:08 AM.



    New Flex Member

  • Ford Flex Members
  • 2 posts

Posted 14 June 2012 - 08:19 AM

Thanks, I will check the manual and the remaining tread depth tonight. I'm planning to talk to a mechanic after work as well.

Custom Search

Privacy Policy Terms of Service ·