is this tire done?
 

these tires are brand new, otherwise i would just replace it. i've never had a puncture like this before so i honestly don't know if this is safe to ride on or not. leaning heavily towards yes, but who knows

is it fixable at all? i'm pretty sure the slice on the right goes all the way through.

Add a small piece of Duct tape over the cut on the Inside of the tire and see if it protects the tube from pinching.

Take the tire off. Look at it from the inside. If the cut even goes all the way through, nine times out of ten, the cut is about a millimeter long. Put a little piece of duct tape/gorilla tape/shoe goo over it and remount the tire.

I've had a cut on my rear tire about 2x the size of the one pictured, and it's been there for nearly 2,000 miles. Because on the inside of the tire, it's almost imperceptible. If the cords are damaged, the cut will keep spreading and you won't be able to stop it.

thanks, i will give the duct tape a try. i rode home very slowly on a new tube with about 30psi and it held up. so as long as it doesn't cut the tube again, it should be safe to ride on?

Yeah, put some Shoe Goo or duct tape on it and ride it till it's ruined.

Got that same tire btw...

I clean the split, put some vulcanizing fluid in it, let it dry a few minutes like when repairing a tube, then squeeze it closed for a bit.

Easier with it deflated.

I'd replace it and keep the old one as an emergency backup.

Yeah, I was not happy when I managed to get a sidewall cut on a tire after only 300 miles. Sidewalls are thin and I replaced the tire. We all make our own decisions, but I would ask myself what would happen if the tire fails on a downhill at 35 mph.

If you decide to use the tire, I would recommend measuring the length of the cut and re-measuring after each ride. Replace if it gets longer.