twitchy car issues after putting new wheels on

[jbailer]

I dont have the specs in front of me unfortunately. What is strange is that one side is still negative while the other side is positive for front toe. But this is within the acceptable range according to factory specs :shrug: I know VERY little about this kind of stuff so I don't know how much this would truly affect driving

Well the toe was within spec during your previous alignment too. It is VERY close to neutral and shouldn't be a problem. I was just saying it might be good to ask them to shoot for toe in of 1/16 (total toe +0.10). A slight toe in can get rid of that twitchiness, too much toe in and you wear your tires out quick.

If you take it to an alignment shop and just say align it, they'll just shoot for green and let it go, they will shoot for the middle of the given spec.

Sponsored

 

[bodam]

What's the actual correct 4 wheel spec?

 

[SteveW]

I dont have the specs in front of me unfortunately. What is strange is that one side is still negative while the other side is positive for front toe. But this is within the acceptable range according to factory specs :shrug: I know VERY little about this kind of stuff so I don't know how much this would truly affect driving

Glad you got your car driving better again!

Regarding front toe settings...realize that turning the steering wheel turns the front tires so if one side is -.01 deg and the other +.01 deg, if you turn the steering wheel a hair then both could be zero.

IOW, if one side was way off and the other in spec with the steering wheel at top-dead-center (TDC) then on the road it would be cocked to one side to get the car to go straight down the road. You make up for the misaligned toe up front by turning the steering wheel to whatever point it takes to make the car go straight. Make sense?

 

[jbailer]

What's the actual correct 4 wheel spec?

There are many specs. There's a Ford factory spec, there's a Ford Performance spec and then there's each person's desired spec based on how they will use/drive the car and what they want out of it. I think there might even be a different spec between PP and non-PP but not sure about that.

 

[AttiS550]

Glad you got your car driving better again!

Regarding front toe settings...realize that turning the steering wheel turns the front tires so if one side is -.01 deg and the other +.01 deg, if you turn the steering wheel a hair then both could be zero.

IOW, if one side was way off and the other in spec with the steering wheel at top-dead-center (TDC) then on the road it would be cocked to one side to get the car to go straight down the road. You make up for the misaligned toe up front by turning the steering wheel to whatever point it takes to make the car go straight. Make sense?

It does make sense, thanks for the insight. Although it is better it is still not as good as it was with the stock wheels on the car. It still feels as if the front tires are being pulled back and forth on bumps in the road which in turn tries to yank the steering wheel out of my hands.

Definitely doesn't inspire too much confidence which is disappointing given the $$ I have put into improving suspension feel. I think my next move is taking it into a professional alignment shop and getting it dialed in to the exact spec I want, the only problem being I am not sure what specs will give me the feel I want. :shrug:

From what I have read it seems that a little toe in on both sides will give me the stability I am looking for. I am definitely willing to give up a little bit of turn in response for more stability.

 

[jbailer]

Tire pressure and compound can effect that as well. I just looked back in the thread and saw your tire pressure. I'd set them down to 32 psi, that should help too. You can't very well change the tread or tire compound without changing the tires but out of curiosity, what tires are you running?

 

[AttiS550]

Tire pressure and compound can effect that as well. I just looked back in the thread and saw your tire pressure. I'd set them down to 32 psi, that should help too. You can't very well change the tread or tire compound without changing the tires but out of curiosity, what tires are you running?

I will give this a shot and see how that changes things. I bought the wheels and tires used off of another forum member, I suspect the tires are pretty old at this point since I believe he actually bought them used originally as well.

They are Michelin Pilot Super Sports, 275/35/20 F and 295/35/20 R, I really want to switch them all out for a new set of Firestone Firehawk Indy 500 tires 255/35/20 F and 285/35/20 R but I need a little more cash first haha

 

[jbailer]

I will give this a shot and see how that changes things. I bought the wheels and tires used off of another forum member, I suspect the tires are pretty old at this point since I believe he actually bought them used originally as well.

They are Michelin Pilot Super Sports, 275/35/20 F and 295/35/20 R, I really want to switch them all out for a new set of Firestone Firehawk Indy 500 tires 255/35/20 F and 285/35/20 R but I need a little more cash first haha

Well those are certainly nice tires. Tire wear can definitely cause problems too, at least with some. I know my stock summer only Pirellis got really bad, twitchy, loud and hydroplaning at about 11k miles and they still had decent tread. I replaced them with Conti DWS06 and all problems were gone. I'm getting a set of those Firestone Firehawk Indy 500 tires also very soon.

 

[AttiS550]

Well those are certainly nice tires. Tire wear can definitely cause problems too, at least with some. I know my stock summer only Pirellis got really bad, twitchy, loud and hydroplaning at about 11k miles and they still had decent tread. I replaced them with Conti DWS06 and all problems were gone. I'm getting a set of those Firestone Firehawk Indy 500 tires also very soon.

I am excited to try those tires, I have read the performance is really amazing and the price is impossible to beat :clap2:

 

[BmacIL]

What are the specs of your wheels? A wider offset (tire center pushed further out) will increase the tire's lever arm on the kingpin axis and increase tire efforts and steering feedback. This can also cause significant tramlining.

 

[AttiS550]

What are the specs of your wheels? A wider offset (tire center pushed further out) will increase the tire's lever arm on the kingpin axis and increase tire efforts and steering feedback. This can also cause significant tramlining.

Front is 20x9 Offset ET 32
Rear is 20x10.5 Offset ET 45

 

[BmacIL]

Front is 20x9 Offset ET 32
Rear is 20x10.5 Offset ET 45

Ok so you're 13 mm further out in the front, not too bad. Front camber will make the front end a little twitchy, and you have enough to do that, but not really that much. I'd try getting just a little bit of toe in, like 0.05-0.08 deg total (0.025-0.04 per side). That will calm the front down a little.

What are your tire pressures?

 

[AttiS550]

Ok so you're 13 mm further out in the front, not too bad. Front camber will make the front end a little twitchy, and you have enough to do that, but not really that much. I'd try getting just a little bit of toe in, like 0.05-0.08 deg total (0.025-0.04 per side). That will calm the front down a little.

What are your tire pressures?

Ok, I will try a little bit of toe in on each side when I get my car re aligned. My tire pressure is 35 all around.

 

[BmacIL]

Ok, I will try a little bit of toe in on each side when I get my car re aligned. My tire pressure is 35 all around.

Go to 32 cold, so they'll be at 34-35 when warm.

 

[DarkestHour]

Go to 32 cold, so they'll be at 34-35 when warm.

Now to trust the car's TPMS or a handheld tool...

Sponsored