LSD = More traction control?

[Thomby]

You can use tape or a paint pen to mark them at the same location (edge of tread or sidewall for easier viewing), do a full rotation of each, and see how far ahead/behind the bigger/smaller one is.

It'll be about 3x what you're seeing in height, and without the potential parallax error.

 

[7Andrei7]

You can use tape or a paint pen to mark them at the same location (edge of tread or sidewall for easier viewing), do a full rotation of each, and see how far ahead/behind the bigger/smaller one is.

It'll be about 3x what you're seeing in height, and without the potential parallax error.

Thanks for the idea! I will try that.

 

[Snicklefritz]

But that isn't spec They should be the same as Michelin 225/40 and 255/35 which are within 2mm OD. Did Continental get a bad batch of tires?

 

[7Andrei7]

There is a difference of 4cm in circumference!
Sadly, the metal tape measure does not completely take the shape of the tire to get a precise circumference, but for estimating the difference between the 2 tires I think it’s quite accurate.

By my calculations it would cause a difference in wheel speed of about 2 km/h at 100 and 3 km/h at 150. Very close to the actual readings.

Later edit: Spoke to the dealer that sold me the rear tires and they asked me to come on the 14th for an oficial expertise of the tires. Very curious as to what the conclusion will be.

 

[7Andrei7]

Just to close this thread, the problem WAS 100% the tires.

I'm on brand new Goodyear summer tires (same specs) since February and the problem has not returned, regardless of how much of a hooligan I am.

Continental did accept my claim and sent me a new set of tires BUT... it appears there is still a 3cm circumference difference between the front and rear tires of the new set. It's not 4cm+ as before but I still expect to have some problems down the road. I'm thinking if I should keep them or try to sell them as 2 separate sets (to avoid problems for others) and switch to a different brand.

I believe there is a bad batch of Continental tires out there and they don't want to admit it because that would mean a recall.

 

[SRV]

Now THAT was an interesting thread - OP, great job getting to the root of the problem!

During Covid, I bought a set of rears for my 993, and specified Michelin 295/30/18. I received the tires from TireRack, and they looked HUGE sitting on the floor, and they were labeled 295/30/18. I measured their width, and they were 320! TireRack exchanged them for me, and I got another brand instead. Not sure why those tires were so oversized.

 

[superflunker87]

We just did the LSD swap on the '23 2.5T over the holidays, along with installing coilovers. Similar to the LSD swap on the '19 2.0T, I did not notice any odd TC or SC intrusion in normal driving. Weather is relatively warm here (65F yesterday) and roads are clear, so no compromised traction anywhere. I'm not comfortable gunning it on public streets, but we have an AutoX coming up this weekend, so we'll see how it does with some proper hooning.

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This is the second LSD swap I've done and while I'm all-too-happy to have done them, I sure as heck would much rather not have to drop the diff again, if I could possibly help it. It's a full 2-day job. So... just to make sure, I changed out the oil seals on both side. Curiously, LEFT and RIGHT sides are different Part Numbers, and they are even color-coded differently, but I can't tell the difference between them. Oh well. It's done.
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I'm thinking of getting a used lsd from a junked stinger and swapping it to my 2018 stinger gt. Do you think I should replace the oil seals? If so, do you have the part numbers?

 

[Volfy]

I'm thinking of getting a used lsd from a junked stinger and swapping it to my 2018 stinger gt. Do you think I should replace the oil seals? If so, do you have the part numbers?

Part numbers are on the package labels in one of those pics I posted.

Changing the oil seals is never a bad idea. Kinda depends on the condition of the used LSD and how many miles it had. I didn't change the seals on my first retrofit but did on my second. Both are holding up just fine. If I were to do another retrofit, I would for sure change the seals... needed or not. Cost is reasonable for the peace of mind.