Check Your Tires!

[dredman]

With us being on longer service schedules than ICE, it's easy to overlook issues that a service advisor would have caught. For example, I left the house this morning and got a low tire warning. The pressure dropped visibly before my eyes so I turned around and got it into the garage safely.

I had no idea the tires were this worn at ~10500 miles.

I'll have to call roadside assistance for this one.

I need a full set after 9600 miles. Admittedly I drive it like I stole it, and I am always in the 'lowest' ride height. Attached photos showing wear - the worst tire is the rear with the thread showing (similar t above) and the other is the front. All 4 tires show the same wear pattern.

 

[Archimedes]

I need a full set after 9600 miles. Admittedly I drive it like I stole it, and I am always in the 'lowest' ride height. Attached photos showing wear - the worst tire is the rear with the thread showing (similar t above) and the other is the front. All 4 tires show the same wear pattern.

IMO, you have an alignment problem. No way should you get that much wear just on the inside of the tire. And you have wear on the sidewall of the tire. How does one even do that? We’re you running low pressures?

 

[BigBob]

I need a full set after 9600 miles. Admittedly I drive it like I stole it, and I am always in the 'lowest' ride height. Attached photos showing wear - the worst tire is the rear with the thread showing (similar t above) and the other is the front. All 4 tires show the same wear pattern.

Is the low ride height a significant factor?

 

[dredman]

IMO, you have an alignment problem. No way should you get that much wear just on the inside of the tire. And you have wear on the sidewall of the tire. How does one even do that? We’re you running low pressures?

I had a puncture, dont recall the side but that would have been close to replacement anyway.

Porsche are checking the alignment, and implied that the lowest ride height might be increasing camber - which would not surprise me given the wear is on the inside of all 4 tires.. The alignment is costing me $1300 :/ I will provide an update once I know.

 

[Archimedes]

I had a puncture,

Ahh, that makes sense.

 

[TomP]

Porsche are checking the alignment, and implied that the lowest ride height might be increasing camber - which would not surprise me given the wear is on the inside of all 4 tires.. The alignment is costing me $1300 :/ I will provide an update once I know.

I just replaced 4 tires last week, The alignment was off.
Dealer was $279 for the 4 wheel alignment.

 

[bsclywilly]

Is the low ride height a significant factor?

and implied that the lowest ride height might be increasing camber - which would not surprise me given the wear is on the inside of all 4 tires.. The alignment is costing me $1300 :/ I will provide an update once I know.

You gain about 0.5deg of neg camber going from regular to low. So yes, it is a factor. Even more so is the ridiculous amount of stock camber in the rear. [Note, this was measured on my CT with 20mm lowering links. The spec. camber values at regular ride height are closer to the 'High' setting in the below table.]

 

[BigBob]

You gain about 0.5deg of neg camber going from regular to low. So yes, it is a factor. Even more so is the ridiculous amount of stock camber in the rear. [Note, this was measured on my CT with 20mm lowering links. The spec. camber values at regular ride height are closer to the 'High' setting in the below table.]

Ta.

Do the chassis settings (normal/sport /+) also have an impact - assuming all on the same chassis height...?

 

[bsclywilly]

Ta.

Do the chassis settings (normal/sport /+) also have an impact - assuming all on the same chassis height...?

No, the chassis settings affect the damper and spring stiffness which doesn't affect alignment like ride height does.

 

[TDinDC]

If right height affects camber, that seems to me to be a massive design flaw, because you would have to optimize for one height and be wrong for all others. At least for something like the CT, that seems to defeat the purpose of having a nearly all purpose vehicle, which is the whole reason I bought mine

 

[bsclywilly]

If right height affects camber, that seems to me to be a massive design flaw, because you would have to optimize for one height and be wrong for all others. At least for something like the CT, that seems to defeat the purpose of having a nearly all purpose vehicle, which is the whole reason I bought mine

You can look at it another way, for commuting or your daily drive, less negative camber is ideal for wear but it is a detriment to performance because under cornering loads and chassis roll the outsides of the tires will be over worked. To maximize cornering performance, more camber , to a point is ideal. By having different ride heights you can have alignment settings better suited for your commute in regular ride height, or a more performance alignment when in low.

That being said the alignment is generally more biased toward performance so uneven tire wear is going to be the norm unless you go away from the specified alignment setting range.

Camber gain is beneficial for a variety or reasons, but mainly to compensate for body roll to maintain even tire contact patch pressure distribution when cornering.

 

[TxnBluDvl]

I had my alignment guy adjust my suspension settings to reduce negative camber in the low setting.

The car spends a good amount of time automatically in the low setting due to highway driving. And I tend to drive locally using the individual setting where I also set it to low.

The amount of time I spend in normal is a smaller percentage. This might mean the car is riding flat without camber in normal mode — but that’s also the mode I use when just loafing around at low speeds and in parking lots, etc.

 

[TDinDC]

You can look at it another way, for commuting or your daily drive, less negative camber is ideal for wear but it is a detriment to performance because under cornering loads and chassis roll the outsides of the tires will be over worked. To maximize cornering performance, more camber , to a point is ideal. By having different ride heights you can have alignment settings better suited for your commute in regular ride height, or a more performance alignment when in low.

That being said the alignment is generally more biased toward performance so uneven tire wear is going to be the norm unless you go away from the specified alignment setting range.

Camber gain is beneficial for a variety or reasons, but mainly to compensate for body roll to maintain even tire contact patch pressure distribution when cornering.

Thanks. I understand suspension theory, but having a geometric change to camber based on ride height is not dialed in or precise. It would work if you are primarily at one height, and only temporarily at another, but even then it’s a compromise. It would have been much better for a car like a Taycan, which is not a track car, to maintain the same camber across all ride heights OR allow specific cambers to be selected for each ride height. Better would be to have a sensor driven automatic dynamic adjustment to have optimum camber for all circumstances. We have the tech. Why not make it an option like everything else? End the ridiculous alignment game.

 

[buruburu]

Thanks. I understand suspension theory, but having a geometric change to camber based on ride height is not dialed in or precise. It would work if you are primarily at one height, and only temporarily at another, but even then it’s a compromise. It would have been much better for a car like a Taycan, which is not a track car, to maintain the same camber across all ride heights OR allow specific cambers to be selected for each ride height. Better would be to have a sensor driven automatic dynamic adjustment to have optimum camber for all circumstances. We have the tech. Why not make it an option like everything else? End the ridiculous alignment game.

You want negative camber gain when the suspension compresses because the suspension is typically compressed during load transfer such as hard turning. When you take a very spirited extended right hand sweeper, the left side of the vehicle compresses. You need the negative camber gain to counteract the positive camber gain that's created by the G-forces acting on the wheels.

I would love to have more than -2 degrees of camber maybe even as high as -2.5, but only if I'm on race tires and on the track. For the streets on extreme performance tires, I usually prefer around -1.5. For me and my driving style, -1.5 on double wishbone suspension gives me even wear across the rubber.

I'd be more likely to attribute the excessive wear due to bad toe settings as that creates scrub and wears out the tires. On a car like the Taycan, I'd probably prefer a zero toe all around. My typical preference is actually slight toe out on the front for faster turn in. But then my 4S also has RAS, so it may not even need the toe out in the front to help it rotate.

Negative camber gain on compression is actually why Double A Arm Suspension is preferable to McPherson Struts. However Mcpherson struts are better for packaging given the limited space near the wheels. However, that's not an issue with EV cars as you don't have to contend with the engine for packaging space.

 

[TDinDC]

You want negative camber gain when the suspension compresses because the suspension is typically compressed during load transfer such as hard turning. When you take a very spirited extended right hand sweeper, the left side of the vehicle compresses. You need the negative camber gain to counteract the positive camber gain that's created by the G-forces acting on the wheels.

I would love to have more than -2 degrees of camber maybe even as high as -2.5, but only if I'm on race tires and on the track. For the streets on extreme performance tires, I usually prefer around -1.5. For me and my driving style, -1.5 on double wishbone suspension gives me even wear across the rubber.

I'd be more likely to attribute the excessive wear due to bad toe settings as that creates scrub and wears out the tires. On a car like the Taycan, I'd probably prefer a zero toe all around. My typical preference is actually slight toe out on the front for faster turn in. But then my 4S also has RAS, so it may not even need the toe out in the front to help it rotate.

Negative camber gain on compression is actually why Double A Arm Suspension is preferable to McPherson Struts. However Mcpherson struts are better for packaging given the limited space near the wheels. However, that's not an issue with EV cars as you don't have to contend with the engine for packaging space.

Yes. I’m an engineer. I used to race cars. I understand fully the circumstances under which you would want camber or not. But that doesn’t change my point, which is valid, that a simple geometric change to camber as a result of height adjustments is simply not good design.

We have the technology. Let’s just dynamically adjust camber to keep as much of the tire patch on the road. It would be better for performance, safety, and tire wear.

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