Steering Issue/Steering Modes/Losing Control

[R5L]

Hi Ryan. First off please cut our friends from across the pond a little slack, No harm was meant. We just have differing styles of humor. Being a sarcastic SOB myself I totally get it.

Now to your car. I want reading your post feeling pretty good that you found a good mechanic right up to when the discussion of tires started. Bottom line, he gave you terrible advise. Adding that amount of air pressure didn't fix your problem, it covered it up.

First off your tires aren't that much different than stock. I have the on my 19' California Special at 32 PSI with absolutely no issues. Now if you were talking 305/325's maybe but not 255's. Also adding that kind of pressure can serous effect the life of your tires and create handling issues. Over inflation is equally as bad as under inflation.

But.......if over inflating your tires to 40psi cold eliminated the problem then I think you might have found your problem. You may have a bad tire. You may also have a defective wheel.

So do what you want, it's your car but I would strongly suggest you keep going. Go back to 32psi as the manufacturer recommends and if your problem returns have your wheels and tires checked.

So, if I have a defective tire or wheel then I would have to assume that all of them are bad, because the car would pull me left right left right just depending on wherever the rut was, no consistency with any specific tire/wheel/or even side of the car. I will keep that as an option to get wheels/tires checked. Thanks for advice.

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[Fly2High]

Thanks for the feedback, I wasn’t aware this could be a common issue with summer only tires. Could this go in line with lower pressure causing the issue to become more significant? I have not been too big a fan of these pirellis, so when they wear out I do plan on upgrading to a nice set.

I would need to ask other GT owners but I have a feeling all GT use 33 psi.

I think the problem is THAT tire. You can mitigate it some by changing to a different tire. All tires will respond to changes in traction, some more than others. I think sidewall stiffness and height may also play into it as well.

Thinking about it for a minute you want a tire that grabs the road, right? Unfortunately, your tire is telling you that the road's traction wants it to go elsewhere and you need to respond. I know that when I enter a construction zone, I slow down and not just because the signs say to. My car tells me I need to.

Suspension also plays into it. Softer suspensions will follow the ground better and handle uneven ground better. Hard suspensions are for smooth roads and help to keep the car level and at a certain ride height among other things.

The combination of suspension and tire results in what you feel.



tire pressure is about maximizing contact patch size, weight support, impact/shock prevention (tires are your first line defense from uneven road and potholes), etc.

In my PP2 manual, they say to lower tire pressures when tracking the car since the tires will heat up more and recommend a hot tire PSI to aim for. Normally all tire pressures are done cold.

 

[R5L]

Ryan, I thought you said the tires and wheels came off a black accent package car. Those should be all season tires not summer. The alignment specs should be virtually identical for a +1 setup like yours.

I have these tires on my CS. 6500 miles and absolutely no issues, even when pushed. Would i buy them again, heck no. AS4's will be the next tires I buy.

You are correct, I just checked for the 20th time probably, they are all season like yours. I was just assuming that they would be just fine being thrown on my 2016, but again wasn’t sure. So if you say they should be almost identical then that narrows it down some. I wasn’t sure if anything needed to be changed putting stock 19 wheels onto a 16 but it sounds like it shouldn’t have been an issue.

 

[Fly2High]

Ryan (OP),

Are all the wheels the same?

I know they all might be the same size but is it possible that they have different offsets?

My PP2 wheels have 24mm offset on the front and 48 in the back. Many Mustangs have different offsets front to back.

Usually, the offset is stamped on the back of the wheel (hub side).

Also, the smaller offset seems to always be on the front.

Is it possible that someone thought they were square(all identical wheels include offset) when they are not exactly?

I had a situation where the car had the rear tire damaged on delivery and they swapped it with a front wheel. I had three 19X10.5 ET24 and one 19x11ET48 in the rear). All tires with 305/30R19. I will say that the car did tramline but I think it tended to kick more to one side. All tires were the same diameter and same tire(Cup 2).

Is it possible you do not have a proper set? Maybe someone bought a set and always used spacers. Maybe they had an accident and had to replace one wheel and purchased the wrong one ( a front offset instead of a rear offset)? Maybe the rear wheels are installed on the front?

I would suggest you check all wheel offsets and make sure they are in the right places.

 

[WD Pro]

I would need to ask other GT owners but I have a feeling all GT use 33 psi.

Euro GT's (255 / 275) quote 32 on the door sticker

Damn it, what did I have to go and say that for ? I've already been politely asked to leave this thread ...

WD

 

[R5L]

I would fire your mechanic If he accepted any money for that solution and let you leave like that. All you did was overinflate your tires rounding out the tread and reduce the contact patch. I have a PP2. They have 305/30R19 tires on them. Far wider than your tires and yet my recommended PSI is 33. Then again, my car weighs more so the 1 PSI difference could be attributed to that. All you will get is more wear along the centerline of the tire and less traction. Yes, My PP2 really tram lined when I had the Cup 2 tires on it. It was significantly reduced when I went over to the PS 4S. It is still there but very marginal. Still with the stock tire size of 305/30R19.

If you need to overinflate your tires then go back to stock. You are really gaining nothing. It also could be the tire and kind of tread it has causing it. Switching tires could help but, if the width is simply too much, you will still get some.

Did a quick search on tramlining and those tires and this is what I found

On a fiat 500 thread they say those tires tramline badly when they start to wear (post #5)
http://www.fiat500usaforum.com/showthread.php?28986-Pirelli-PZero-Nero-s-LOUD!!!!






Here is a guy with a WRX with tramlining issues with those tires(post #6)
https://forums.nasioc.com/forums/showthread.php?t=1841569



Now, this could be the same guy.


Here is a corvette complaining of the same thing(Post 12)
https://www.corvetteforum.com/forums/c5-general/1230890-who-here-has-pirelli-p-zero-neros.html






This is a guy with an Integra Type R who also has tramlining (post 14)
https://www.odyclub.com/threads/pirelli-p-zero-neros.16301/





I think your issue is the tires. Sounds like a bad tread pattern for several cars once they start to break in.

Wow this seems like we may have found the solution. But again, I trust this mechanic as he has fixed many cars in my family and never had any issues. When he called me he told me, he checked all the things I listed and he couldn’t find anything, that’s when we just decided to try higher pressure and see if it does anything. Which it did. Now, those posts you linked make me really feel like it’s the tires as it seemed like an issue on all kinds of vehicles. Seems like upgraded tires are in the near future. Thanks for the feedback very helpful.

 

[R5L]

Ryan (OP),

Are all the wheels the same?

I know they all might be the same size but is it possible that they have different offsets?

My PP2 wheels have 24mm offset on the front and 48 in the back. Every Mustang has different offsets front to back.

Usually, the offset is stamped on the back of the wheel (hub side).

Also, the smaller offset seems to always be on the front.

Is it possible that someone thought they were square(all identical wheels include offset) when they are not exactly?

I had a situation where the car had the rear tire damaged on delivery and they swapped it with a front wheel. I had three 19X10.5 ET24 and one 19x11ET48 in the rear). All tires with 305/30R19. I will say that the car did tramline but I think it tended to kick more to one side. All tires were the same diameter and same tire(Cup 2).

Is it possible you do not have a proper set? Maybe someone bought a set and always used spacers. Maybe they had an accident and had to replace one wheel and purchased the wrong one ( a front offset instead of a rear offset)? Maybe the rear wheels are installed on the front?

I would suggest you check all wheel offsets and make sure they are in the right places.

I will check that later thanks for the idea

 

[Bikeman315]

Ryan (OP),

Are all the wheels the same?

I know they all might be the same size but is it possible that they have different offsets?

My PP2 wheels have 24mm offset on the front and 48 in the back. Every Mustang has different offsets front to back.

Usually, the offset is stamped on the back of the wheel (hub side).

Also, the smaller offset seems to always be on the front.

Is it possible that someone thought they were square(all identical wheels include offset) when they are not exactly?

I had a situation where the car had the rear tire damaged on delivery and they swapped it with a front wheel. I had three 19X10.5 ET24 and one 19x11ET48 in the rear). All tires with 305/30R19. I will say that the car did tramline but I think it tended to kick more to one side. All tires were the same diameter and same tire(Cup 2).

Is it possible you do not have a proper set? Maybe someone bought a set and always used spacers. Maybe they had an accident and had to replace one wheel and purchased the wrong one ( a front offset instead of a rear offset)? Maybe the rear wheels are installed on the front?

I would suggest you check all wheel offsets and make sure they are in the right places.

Good call if they were aftermarket wheels but Ryan says he has factory Black Accent wheels so the offsets would be the same

 

[Fly2High]

Euro GT's (255 / 275) quote 32 on the door sticker

Damn it, what did I have to go and say that for ? I've already been politely asked to leave this thread ...

WD

You made me go and double check. Yeah, my PP2 is 33PSI. Could be different due to sidewall thickness or just suspension tuning. No idea. To me, it sounds like a GT is between 32 and 33 PSI.

I do not believe PSI is different in Europe than here although that did cross my mind.

 

[Bikeman315]

Wow this seems like we may have found the solution. But again, I trust this mechanic as he has fixed many cars in my family and never had any issues. When he called me he told me, he checked all the things I listed and he couldn’t find anything, that’s when we just decided to try higher pressure and see if it does anything. Which it did. Now, those posts you linked make me really feel like it’s the tires as it seemed like an issue on all kinds of vehicles. Seems like upgraded tires are in the near future. Thanks for the feedback very helpful.

We do not know your mechanic so we will trust what you say is true. Trying the higher pressure eliminated the issue but did not find the cause of it.

Just find someone with a S550 and swap wheel and tires. If the problem persists then they are not your problem. My gut tells me your issues will stop once you change.

 

[Fly2High]

Good call if they were aftermarket wheels but Ryan says he has factory Black Accent wheels so the offsets would be the same

Not sure.

This website (https://www.wheel-size.com/size/ford/mustang/2019/)
lists two 255/40R19 tires each having a slightly different offset for an Ecoboost. Not sure if one is front and the other back. They are both for 255/40R19 tires but the wheels are only differ in their offset.

Now, if they came off a GT, they are definitely different offsets. There, they list Fr and Rr together. You can see the red Plus sign there to open the rear size wheel data.

Not sure but worth a check.

 

[Bikeman315]

Not sure.

This website (https://www.wheel-size.com/size/ford/mustang/2019/)
lists two 255/40R19 tires each having a slightly different offset for an Ecoboost. Not sure if one is front and the other back. They are both for 255/40R19 tires but the wheels are only differ in their offset.

Now, if they came off a GT, they are definitely different offsets. There, they list Fr and Rr together. You can see the red Plus sign there to open the rear size wheel data.

Not sure but worth a check.

The Black Accent wheels are 8.5's and are the same for both the EB and GT.

 

[R5L]

The Black Accent wheels are 8.5's and are the same for both the EB and GT.

They came from a 2019 GT if that helps any.

 

[Bikeman315]

They came from a 2019 GT if that helps any.

It doesn't

Ford Mustang 2019 2.3 EcoBoost

255/40ZR19 96W

8.5Jx19 ET42.5

5x114.3

Ford Mustang 2019 5.0 Ti

255/40ZR19 96W

8.5Jx19 ET42.5

5x114.3

 

[Echo4papa]

A couple of thoughts, just because I'm bored...

Tire pressure recommendations are cold pressure, right? So, if he's pushing up closer to 40 hot, it's a good bit lower cold and probably has been driving around underinflated. I was running my own ~35 hot but once I bought a cordless inflator and filled them to 35 cold, they ran around 39/40 hot.

Second, the most telling thing to me was that his mechanic drove the car and said it seemed fine.
I'm guessing the underinflation made the car tramline just a bit, definitely more so than it did on the original, skinnier tires. OP is hypersensitive to it, but it's not abnormal just not what he was used to originally. Properly inflating the tire corrected the issue, better tires (eventually) and proper inflation are the best course of action.

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