Sudden rear instability with new Conti Sport Contact 5?

Hi

For those in a hurry, here are the results of this action.


My Passat feels like it's veering to the rear


In the winter, I drove with 205/55 R16 tires.
Front: Dunlop 4D 5mm
back Dunlop 3D 5mm

now 235/45 17
Front: Conti SportContact 3, 7mm
rear new Conti SportContact 5 7mm

If I suddenly steer sharply, it feels like the rear end initially lags behind, and then only turns later.
It really feels humble... that's not how I know my Passat.

My Idea:
The WRs are so imprecise because they are coarse, which makes them tend to understeer.

Now, with SR, the following happens:
The front wheels immediately steer, because they have good grip.
The rear rubber bushings of the front control arms have excessive play.
This means it takes a little time for the steering to be transmitted from the chassis.
This feels like "the bad guy is coming."

Is this plausible?
Say: Replace the front suspension control arm bushings quickly so that the rear feels more precise again?

m;

I have no idea, but I can hardly imagine it. However, this is not the ultimate reason for a new acquisition...??

What is the sidewall height and stiffness of the tires? Tires with high sidewalls tend to lean towards the edges due to (for the vehicle) low or comfort-oriented tire pressure. In a cornering maneuver, the flanks are initially "pre-stressed" before the task of lane keeping is consistently taken over.

Quote:

If I suddenly steer sharply, it feels like the rear end initially drifts forward, and then only turns with it.

Will the rear end then come around or not?

First, properly inflate the tires, then continue to see

Does the side wall of the tire still play a significant role at 45 degrees?

It's probably less likely to be the issue with the front suspension bushings.

Quote:

First, properly inflate the tires, then continue to assess the situation.

That was also my first thought.

When is "reasonable" achieved?

m;

Hello Martin,

are the wheel dimensions the same? With my old winter tires, the vehicle also tended to understeer in the rear. The tire depth was 2mm different, the tires were the same size.

Best regards, Rainer

Throw the facts on the table!

So, eine Reifenhöhe von 45 bedeutet "im Wesentlichen", dass der Reifen nicht so stark in Querrichtung zur Laufrichtung arbeiten kann. Aber auch hier gehen die Reifenhersteller unterschiedliche Wege. Einige machen die Flanken weicher, um dadurch einen Komfortgewinn zu erzielen. Auch die Dicke und Breite der Profilblöcke und -streifen spielen eine Rolle. While many small and delicate profile blocks provide grip, they also cause other effects, including increased wear and tear.

If the rear axle feels strange, try adjusting the tire pressure first. Start with the rear tires at full pressure plus about 0.3 bar, and then drive the same distance again. The load transfer reactions should also be provoked in the same places to make the effects on handling comparable. It's best to fill the tank completely, so that there's little left over and it doesn't distort the impression. With tire pressure, you can experiment a lot, and the following steps have proven to be effective: start with 0.2 bar adjustments, and if you want to notice a difference, you can start at 0.3 bar above the manufacturer's recommended level.

Hi

Winter and summer tires are completely different.

6x16" Steel to 7x17" Aluminum.

However, I've made this switch 7 times before, and each time I was happy to have those wide summer tires with good grip again.


This time, I made a braking maneuver in the first sharp turn... right into the ditch


Since I've now also received the advice to "just get used to the new tires first," I'm going to wait a little longer... and hope.

m;

Okay, let's go and maybe be especially careful about the wet conditions.

I can present a scientifically-oriented study starting on Monday - because then I will also receive the Conti SC5 (although in 235/40 1. Keep an eye on it.

So, meine "Erfahrungen" mit Conti sind -> "... einmal und niemals wieder ...".

With the Contis, I was able to achieve the most wonderful drift angles on the AXR. "However, when it suddenly became possible to dispose of them through the VA, I discarded them despite the remaining 6mm profile."
"As a Continental employee, I didn't even care about the percentages. I won't be buying anything like that again."

Okay. It's up to the tires.

I also have this "weird" feeling in my stomach when I suddenly steer sharply into a turn, for example. In normaler Fahrweise ist dies kaum/nicht bemerkbar, aber vielmehr, wenn man sein Auto gut kennt.

Very difficult to describe, here's an attempt: Balloon tire with too little air. The rear end "floats" around - this is definitely not a pleasant feeling. "On 'Comfort', it's even significantly worse than on 'Sport'..."

235/40/18 Sport Contact 5 @2.5 Bar, Week 47/13.


I will talk to my driving instructor again tomorrow, maybe he has an explanation.

anywhere wrote:

235/40/18 Sport Contact 5 @2.5 Bar, Week 47/13.

My idea was to "over-exert" myself:

235/45/17 Sport Contact 5 @2.7 bar, KW 0x/14

Especially with the pronounced rear-end slip, the slightly inflated tire only runs on the inner "half". First, you need to remove the weight, until there is enough "load" on the side to press the entire tire onto the ground.

That would be exactly what was observed: First, the rear end loses grip, and then it sticks in the corner just like normal.

But I also feel that it's getting better - which, in turn, supports the "just start doing it" theory.

m;

The tire should stand out with its full tread width, and the air pressure should be adjusted experimentally, as well as when the load changes.

...that it will get better = Abrasion of the running surface through use + Creating a conditioning effect.

=> that might be about 1cm, which is the amount the tire is deformed. I estimate it was around 10-20

My dealer says that I should add +0.3 bar, then it will be finished.

At least, he said that he had asked a lot of questions about it - so, for me, this rules out a "misinterpretation" or "over-sensitivity," and everything is fine. One gets used to everything

I wrote this on the 25th. Try it with increased pressure.