Replacement tire problems


GT@50

GT Owner
Mark II Lifetime
Dec 14, 2019
852
Issaquah
Ever done one at 70mph?
Burn out, no, donut, yes. Does the car do something to the engine during a 70MPH tire spin? An archaic trac control?
 

PeteK

GT Owner
Mark II Lifetime
Apr 18, 2014
2,267
Kalama, Free part of WA State
As far as I know from reading info here and in the manual, the ABS and ECU are separate systems. Kendall or anyone else, do you know differently? Is there any signal from the ABS to the ECU? If they are separate, then the ECU does not compare front and rear wheel speed, so GT@50 probably is correct that something else is causing the behavior.

However, Mark06GT: you should still insist that the dealer put the correct size Bridgestones on the car. They should know not to put significantly different tires sizes on a modern car with ABS. Even if it does not fix the loss of power, it will ensure your ABS works correctly. Then see if the behavior continues.
 

PeteK

GT Owner
Mark II Lifetime
Apr 18, 2014
2,267
Kalama, Free part of WA State
And Mark06GT, one other thing: check the intake boot and vacuum/boost hoses on the intake side. One of those coming loose will cause similar symptoms.
 
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GT@50

GT Owner
Mark II Lifetime
Dec 14, 2019
852
Issaquah
Yes, it would take a wire from ABS mod to ECU to affect the engine. Does it have one? Dunno. Was trac control in the works but not the budget but some precaution was programmed? Definitely not many cars with the stagger the GT's have. Possible player?
Fred Ward, "How does it work? Who cares, it just does!"
 

Mark06GT

GT Owner
Mark II Lifetime
@GT@50
I don't buy it. About all I could imagine happening would be an ABS light if tire stagger front to rear was too large. There's no traction control so the engine would keep running fine. The computer doesn't know what gear you're in so a fault related to RPM vs MPH wouldn't be possible. If it's going into "failsafe", there should be a code that caused it. What is that code?

The dealer said there was no code associated with the event, but the ABS and handbrake lights did go on every time it happened.



@centerpunch

What are the exact sizes (width and aspect ratio, molded on the side) of the tires they put on the car?


I'm not near the car now, so I don't know the numbers, but the tires they put on are significantly lower profile than the originals.




@centerpunch

MONTHS?

WTF? Are they waiting for the tires they installed to magically change size?

The answer is, duh, to take off the tires that they should never have installed on the car, and install tires that are the correct size.

The oem Goodyears and the Bridgestones have diameters almost exactly the same, and have been used by hundreds of GT owners.

Put the Bridgestones on and find a new dealer who has an IQ above 50.


Yeah, I've been preoccupied with other things. This wasn't a top prioroity. I've got stuff cleared up now and can focus on this.



@GT@50

Yes, ABS looks at SS's. I doubt the engine looks at them.
I'm saying that, if the tires aren't causing an ABS code, smaller tires in the rear is equivalent to the 3.9 ratio, and the 3.90's don't cause engine problems. His engine problem is something else


I'm pretty certain it's the tires. There were no problems before the tire change and the problem started happening the same day they put on the new rears. Too much of a coincidence to be anything else.

@HNS

Where is your dealer located? Sounds like they screwed the pooch.

John Kennedy Ford, Phoenixville PA. It's where I purchased the car in 2007. They've been good up until now. Needless to say, I'm disappointed with the whole tire thing.



@PeteK

As far as I know from reading info here and in the manual, the ABS and ECU are separate systems. Kendall or anyone else, do you know differently? Is there any signal from the ABS to the ECU? If they are separate, then the ECU does not compare front and rear wheel speed, so GT@50 probably is correct that something else is causing the behavior.

However, Mark06GT: you should still insist that the dealer put the correct size Bridgestones on the car. They should know not to put significantly different tires sizes on a modern car with ABS. Even if it does not fix the loss of power, it will ensure your ABS works correctly. Then see if the behavior continues.

I totally agree. That will be my project this week.



And Mark06GT, one other thing: check the intake boot and vacuum/boost hoses on the intake side. One of those coming loose will cause similar symptoms.

I will take a look, but I would hope they would have noticed that.




Thanks all for your help. With your input, it should be easier for me to get the dealership to do the right thing an replace the tires.
 

Mark06GT

GT Owner
Mark II Lifetime
And just as a double check...these are the correct tires?

1661666670482.png

1661666694127.png
 
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2112

Blue/white 06'
Mark II Lifetime
 
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Derry

GT Owner
Mark II Lifetime
Apr 5, 2006
339
buffalo, NY
FWIW I put Bridgestone 235/45R18 on the front and they worked fine as well.
 

quahog

GT Owner
Mar 12, 2017
36
Cape Cod
so it seems Bridgestone is the only option available as in 2023 ? Been out of the loop hibernating for some time, quahog
 

Art138

GT Owner
Mark II Lifetime
Jan 4, 2011
624
Weston,FL
so it seems Bridgestone is the only option available as in 2023 ? Been out of the loop hibernating for some time, quahog
Several other options but consensus is that they (Bridgestones) work best for everyday driving.
 

twobjshelbys

GT Owner
Jul 26, 2010
6,053
Las Vegas, NV
Several other options but consensus is that they (Bridgestones) work best for everyday driving.
And occasional track use. Best overall choice.
 
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2112

Blue/white 06'
Mark II Lifetime
^^^^ This
 

roketman

GT Owner
Mark IV Lifetime
Oct 24, 2005
7,994
ma.
Check the tire thread and call Bill st Radial tire. He has them in stock
I have no affiliation other than being happy customer!
 
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extrap

GT Owner
Mark II Lifetime
Jul 16, 2020
1,751
Gainesville FL
@roketman Ron, I don't wanna put words in your mouth, but I have a feeling you have a typo in that post.
 
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roketman

GT Owner
Mark IV Lifetime
Oct 24, 2005
7,994
ma.
@roketman Ron, I don't wanna put words in your mouth, but I have a feeling you have a typo in that post.
Thanks! You are correct!
 
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quahog

GT Owner
Mar 12, 2017
36
Cape Cod
Is there is a GT service friendly place in Mass> ? I am told anyway . Tires/ OEM are past due for me . Roketman sounds familiar here locally as a regular contributer , I can pull the rims and head to nearest place from the cape come spring. Ideas ?
 
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roketman

GT Owner
Mark IV Lifetime
Oct 24, 2005
7,994
ma.
Is there is a GT service friendly place in Mass> ? I am told anyway . Tires/ OEM are past due for me . Roketman sounds familiar here locally as a regular contributer , I can pull the rims and head to nearest place from the cape come spring. Ideas ?
Where are you on the cape?
I’m in Falmouth
I used a place in Waltham
But I recently (last spring ) had new tires put on my carbon series. I had Herb Chambers in Braintree do them . They are the New Gt authorized repair shop. They work out of the truck center. Ask for Derek (781) 849-7700
 

quahog

GT Owner
Mar 12, 2017
36
Cape Cod
Thanks for update , I am in Orleans . We have several GT's in the area ! 2 in wellfleet , eastham one orleans one use to be one in P town and you in falmouth one in hyannis . I have access to a current range tire machine and hunter alignment lift at work in chatham. Tires may be more of a challenge for this 70 year old , they are not 165 - 15's !!!! quahog
 
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fjpikul

GT Owner
Mark IV Lifetime
Le Mans 2010 Supporter
Jan 4, 2006
11,475
Belleville, IL
Yeah, well, Rocketman ain't no spring chicken.
 
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roketman

GT Owner
Mark IV Lifetime
Oct 24, 2005
7,994
ma.
Thanks for update , I am in Orleans . We have several GT's in the area ! 2 in wellfleet , eastham one orleans one use to be one in P town and you in falmouth one in hyannis . I have access to a current range tire machine and hunter alignment lift at work in chatham. Tires may be more of a challenge for this 70 year old , they are not 165 - 15's !!!! quahog
There are some great cars and coffee in Dennis
Also, Heritage Gardens in Sandwich does some great car events