I have been looking at other tires but I will most likely buy Grand Prix.
My wife’s bike has Grand Prix 4000 tires on it that are older than mine and still look great.
I looked at my tires again and it looks like it is separating along a seam where the sidewall meets the tread part of the tire. It’s more than a crack.

I ran a Vittoria Corsa tires briefly and I did notice there was starting to be a little bit of tread separation like what you are showing here. I think this is inherently a problem with their 'open tubular' construction with the various layers glued together flat. When you inflate the tire and force it to be round, it wants to separate. Factory produced tires like the Continental GP5000 come out of the mold all fully formed and pre-shaped in the shape of a tire, so there is nothing to separate.

https://cimg6.ibsrv.net/gimg/bikefor...10e067971.jpeg

I wanted to tell you I bought some Vittorias from Bikeinn and I put them on my older bike today. They look great and I'll take a ride on them tomorrow.
They were $17 each, can't beat that. They don't have free shipping but along with these tires and some other stuff I'm ahead, even paying shipping.

The shipping is slow but the prices were great.
Vittoria Zaffiro Pro V Graphene 2.0 700C x 28 road tyre, Black | Bikeinn (tradeinn.com)

Never mind. My lbs website shows them in stock but when I called they said they are in their warehouse and will take 7-14 days to get to the shop. They have to order them so I may as well order them myself.

I do have another option. On FB marketplace a guy near me is selling new GP 4000s for $20 each. They are 25mm instead of the 28mm I was wanting but for that price why not?

They stopped making those nearly a decade ago, so I wouldn’t bother.

Oh. I didn’t know they could be that old.

I've purchased Vittoria tires on three separate occasions from two different bike shops. All three pairs developed extensive cracking in maybe 2 or 3 years. I'll never buy them again.

This is more than just cracks. Look at the last pic I posted a few posts above this one. The tread section is separating from the sidewall. This has me really not trusting Vittoria again.

Ooh, yeah, that's bad, did not see those posts. Mine all look like the photo in your second post. After 2 or 3 years. Three separate pairs. Unacceptable.