I have just discovered that one of my tires is bald to the point of nearly having a hole in it. I thought that until I am able to get into the shop to get new tires in a couple of days, I could reinforce the spot to prevent further punctures in that area. I decided that since I have no thick rubber, I would use a strip of plastic from a vitamin bottle. I cut a long strip and rounded the edges, and fit it into the tire, two layers thick, then inflated the tire as usual. It seems to be fine, although I haven't ridden on it yet. I figured that since it conforms more or less to the shape of the tire all the way to the bead, and that I removed any sharp corners, it won't damage the tube.
Is there any reason why this is a bad idea, or is it a fine jerry-rig for the next couple days in which I'll do probably do about 80 minutes of riding?
Please let me know your thoughts. Pictures are attached. Thanks!

If you cut through the casing the tire will pull apart in that spot and the reinforcement won't do any good. You're probably better off covering the outside of the casing in shoe goo or something, if you really don't have any other choice.

Hell, yes!
But at least the blowout won't be on the front tire.

Park sells a self-stick boot specifically for that purpose. However, I used one once upon a time and discovered, even with the self-stick, they do not stay in place indefinitely. So it's the kind of thing you do when you're out on a ride and have a problem- you hope it will keep you from being stranded. But not the kind of thing you do to "fix" your tire.

A piece of an old tire should make a good boot, for that matter.

I would duct tape the weak area of the tire and order a new tire SOON.

A DIY tire boot.

When I have need for one I use a dollar bill. Actually, I tell other people that it's better to use a ten because you're more likely to remember to take the ten out and replace the tire.

Mr Tuffy Liners would be a better solution than plastic

Plastic? Use a Credit card.. buy a new tire and Next time dont lock up your rear-brake/ or skid stop, and make that flatspot.

after some consideration I decided to use instead a couple of strips of corrugated cardboard. we'll see how that goes.

Exactly!

I wonder if repair patches designed for tubes would stick to the insides of tires (as a temporary repair, of course).

I wonder if repair patches designed for tubes would stick to the insides of tires (as a temporary repair, of course).

The answer is yes, if the patch is big enough.

Park Tool Co. » TB-2 : Emergency Tire Boot : Tube & Tire (for bike tires)

Opentip.com: Schrader Bridgeport 13-128 Tire Repair Boot 7-3/8" 1 Per Bag (for car tires)

It is also nice to have on hand a decent amount of rubber cement. The little tubes that come in a patch kit never are good for more than one use in a hot climate so I use them only on the road and keep a jar of rubber cement at home for regular at-home repairs. You can buy a 4 oz jar at any office supply store for a couple bucks and it lasts for years.

+1

The exposed cords are what holds the tire together. Wear through them enough to compromise their strength, and the tire will burst. The internal plastic liner might be strong enough to bridge the damaged area and buy you a bit more time than otherwise, but won't do much to stop the clock, and you can expect wear through and failure within a few miles (few meaning 10-100). For a commuter, it might be OK in a pinch, but I wouldn't leave town.

BTW- that kind of uneven wear often means the wheel is out of round. What you might do (again, in a pinch) is to rotate the worn area to a low spot on the wheel, where the wear rate might be slower. You might also try to find something to glue over the outside.

For 80 minutes? If your walk of shame begins after 40 minutes, how long will that add to your trip home?