I just punctured my Michelin pro race tire while I was riding today. There is now a 3/16 inch slice in the tire and the threading is visible. Is it possible to repair the tire with rubber cement (or any other means) or will I have to throw down for a NEW TIRE????

All of my tyres have serious nicks and slices to the rubber and holces of that size caused by glass splinters, but none has ever got larger or lead to more punctures. You cant repair the rubber, but a tyres strength comes from the layers of fabric, not the rubber.
I have replaced tyres with damaged sidewalls, these are places where slits can grow larger.

When I have that problem, I cut a half-inch-by inch piece of old innertube and glue it on the inside of the tire over the cut. You need a rubber glue that will stay soft after drying. I use O'Neill's neoprene wetsuit repair glue. I just happened to have it for my own wetsuit repair, but there must be other glues like it out there. This kind of repair helps prevent potential destructive road debris from working its way into your tire and tube.

Rich

Sewing or gluing the hole closed has never worked for me. What has worked is, as other posters mentioned, gluing or positioning some non-stretchy material over the defect on the inside of the tire. Materials that work well are: Tyvek (priority mail envelopes FREE from the USPS), potato chip bags (recycle, baby), and sidewall from old tires cut to size. Also, if the sliced tire is currently on the rear wheel, I'd swap it with your front wheel to help the repair last longer. Defects on the tire's sidewall are tougher to repair, but still possible - I repaired an inch long gash on my sidewall with Tyvek, and the repair lasted 500 miles!

Good luck!
BK

Ive had a front wheel blowout, and a rear wheel blowout, and I much prefer the latter. Keep a dodgy tyre on the rear.
Booting the tyre with various materials is really a get-you-home measure. If the tyre is damaged enough that you need to repair it, it needs to be replaced ASAP.

My experience has been that a compromised tire mounted in the rear is far more likely to "blow" than one in the front. The only times that I have had tires catastrophically explode on me is when the inner tube sneaks between the tire bead and the rim (improper mounting). All other flats I've had, with even the scariest looking jury-rigs and defects, go with loud "hiss" and a gradual loss of pressure. Of course it is better to replace a damaged tire, but it is rarely imperative.

IMHO
BK

Go to the automotive store and get a tire patch kit. This is not a tube patch kit. Rather, there will be a thick, strong patch in the kit which is specifically for patching tires. These work pretty well.

Next, you have to fill the hole in the rubber part of the tire. Even though the patch will support the damaged threading from the inside, you want to keep debri from entering the cut. I use Shoe Goo, just because I have not found anything else to use.

The best thing to do is buy a new tire. It sucks but that's life right?
The repairs everyone mentioned are good. If the threads aren't torn up, it should work for you fine.
If you do it, PUT THE REPAIRED TIRE ON THE REAR WHEEL. Do not put it on the front. If the sidewall gash is going to pop again, most likely it will be when you are putting pressure on the sidewall--like a high speed turn.
You have no chance of saving yourself if your front tire blows in such a case. The rear is much more 'save-able'. If the rear blows sooner (because it is carrying more weight) so what? At least you didn't leave 50 meters of skin on the pavement.

Remember- front tire is for CONTROL. Rear tire is for drive.

thanks for this advice!! i was just about to chuck my torn GP3000!! I think i'll repair it and save it for use on the trainer this winter

I just had the same thing happen to me a few weeks ago during a cross-state bike tour. After I put a boot on the inside of the tire I repaired the cut with a drop of super-glue. I then rode an additional 450 miles on the tire.

When the tire is deflated put a drop into the cut. Then push it together. After the glue sets inflate the tire. My friends who run tubless tires on their mountain bikes tell me that is the standard procedure for puncture repaire on tubless.

Also, like the others have said here, it's safer to put the repaired tire on the back.

Good Luck!

Two days ago I got the worst tire slash I've ever had. I was on a great local ride when I came upon a whole lot of broken pieces of something spreading from my bike lane to across the road. It looked like broken crockery. I had been going pretty fast so I tried to maneuver myself through it. But, alas, a loud pop told me that I had failed. When I checked my rear tire, I saw it was gashed from the middle of the sidewall to the middle of the tread. The road hazard was some kind of opaque glass. There was just no way that that tire could be repaired, even to get home. I walked to the nearest phone and had to call home to get picked up.

Fortunately, that Conti GP 3000 only had a month or two of tread left on it and I had prepared for its demise by buying a replacement about a month ago. As soon as I got home, the first thing I did (even before I took my bike off the rack) was to call the county road department and report the hazard. They said that they would clean it up ASAP. A couple of hours later, I had to go by that spot in my car, and it was cleaned up.

Rich