Razor blade in my tire.

[FT92]

i wouldn't worry about it myself...if you really need to stop at a tire dealer , have hem check it out but it doesn't look like a problem several years ago i had 8 ply tires on a pickup i owned then , somehow tore a 2 inch chunk about a 1/4 inch deep out of the side wall..drove it like that till the tires were almost bald

 

[ARCOgraphite]

Yep no leaking only noticed because I saw the metal glinting in the sun while I was walking to the car.

I would just rotate it to the front if it isnt there already, that way if it looses air, you will likely retain vehicle control.
Do you do any High speed highway driving?
Decade ago I had a front tire go on our Arco service station drag car when I was forced to street drive it due to my DD being broken.
Tire disintegrated at 100MPH and took out most of the inner and outer fender. I never lost control - in fact it steered better

 

[CapriRacer]

I wouldn't worry about it. The steel belts are the outer layer, and unless you can see a glint of severed steel in the bottom of that cut, I don't think there is any real damage to the structure of the tire, just a bit of a cut in the rubber that already has blocks and sipes.

I'd be curious what @CapriRacer has to say, he's the expert on this...

It's deeper than the tread pattern. It may have reached the belt. What you want to look for is a bulge - use a GLOVED hand to feel for it. This may take a while to appear.

No bulge = likely good!

Bulge = replace it.

I would check again in a month or so.

 

[Snagglefoot]

If it's only in the tread I'd ignore it. Like Jetronic says, you have another sipe now. If worried, you could take a probe of some sort, pick, screwdriver, whatever, and verify that it's not deep.

What works well is a 1 inch long pin with a head on it.

 

[PimTac]

I'll probably have someone look at just to check. I don't think it can be patched though the cut is about 4 inches long.

4 inches? That doesn’t sound good. I would definitely keep an eye on it or have it checked.