Close

Results 1 to 8 of 8
  1. #1

    Default Bad matching tires dimensions bring Limp mode

    In France, we must get European certifications with CE tags on our sidewalls tires, but there is not a too much choice regarding dimensions, even less GT factory size who are not available anymore.
    First choice has been 245/40X18 in front and 325/30X19 in rear (Michelin pilot sport cup 2) to not lose too much thickness, alas this choice was bad and the car entered in Limp mode, It took me a long time to understand where the problem came from🙄🙄.
    Today, i swap the four wheels from another GT with Stock wheels and tire, go for a long road test in fact to be sure ; no limp go home problem anymore ! It was realy incorrect tires size who enter limp mode.
    Ford factory sizes are 235/45X18 front = 669 mm diameter and 315/40X19 = 735 mm. The ratio between front and rear is 1.098 (9.8%)
    GT friend's sizes are 245/40X18 front = 653 mm diameter and 325/30X19 = 678 mm. The ratio between front and rear is 1.038 ( 3.8%)
    My personal GT sizes are 235/30X20 front = 649 mm diameter and 345/30X20 = 715 mm . The ratio between front and rear is 1.101 (10.1%)
    Normaly, factories tolerance regarding ABS moudules are 5% up or 5% below, so 1.098 - 1.068 = 0.06 (6%) outside factory tolerance!
    I know SCT tuners, who are able to correct speedo reading when you change tires heigth or differential gear ratio ,* I don't think they could resolve the problem because the speedo sender signal is not the same signal than the ABS wheels sensors.
    Can anyone confirm or refute my reasoning ?
    Thank you

  2. #2
    Le Mans 2010 Sponsor 06fordgt's Avatar
    Join Date
    Nov 2006
    Location
    Toronto Canada
    Posts
    1,697

    Default

    had no idea there was limp mode on the 05/06 cars!

  3. #3
    GT Owner Xcentric's Avatar
    Join Date
    Jul 2012
    Location
    Myakka City, Florida
    Posts
    4,957

    Default

    I never heard of anyone running 20s front and rear. +2F/+1R wheels and small diameter tires? Why are you and your friend using tires that are shorter than stock? Are your GTs lowered a lot?

    Check this thread (post #7) http://www.fordgtforum.com/forums/sh...n-acceleration. Guy had limp mode and thought it was ABS. Unfortunately, the real problem was never reported. But, a GT expert says "...the diameters could be too close of a ratio from front to back causing the ABS module to limit speed to around 50mph." You seem to have the opposite...too big a ratio. Perhaps that causes the same result, as you suspect.

    Is that your GM station wagon pulling the trailer? How the hell do you fit through French villages?
    Last edited by Xcentric; 11-08-2018 at 11:59 AM.
    Team Xcentric - The only two-time podium finishers in Ford GT Road Rally history.

    "If you buy one and don't drive it...well, what's the point?"

  4. #4

    Default

    I used this 20 rims size because as explained above we cannot find 13 year old dimensions with European certifications, and insurances companies will not cover responsability if accident occur. Also GT with 20 look very pretty.
    Concerning my friend, he want to keep factory wheels, but no more tires available again, I gonna swap 245/40X18 by 245/35X18 in fact to keep in 5% manufacturer's tolerance.
    I had already read the GT guy post, i agree
    Regarding my Roadmaster, don't worry, i own this station wagon since 22 years and I really like to drive it through our pretty little villages! Anyway i don't have the choice, when i go to the track, i use slick tires they are strictly forbidden on open roads in France

  5. #5
    Blue/white 06' 2112's Avatar
    Join Date
    Feb 2010
    Location
    People's Republic of Washington State
    Posts
    4,367

    Default

    Try Bridgestone Potenzas 265/40 -18" in front & 345/35 - 19" in the rear on stock diameter wheels.

  6. #6

    Default

    Not availables in France

  7. #7
    Blue/white 06' 2112's Avatar
    Join Date
    Feb 2010
    Location
    People's Republic of Washington State
    Posts
    4,367

    Default

    What do the Porsche and Enzo owners do?

  8. #8
    *UK Support* GT101's Avatar
    Join Date
    Jan 2010
    Location
    Colchester, Essex, UK
    Posts
    266

    Default

    We can easily ship you Bridgestone RE050 in 265/40R18 and 345/35R19 from the U.K.

    As suggested these are the optimum sizes for stock wheels.


    Sent from my iPhone using Tapatalk

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •