We need much more information regarding your idea SmartTire.
To start with, where do you want to place this U-wire? Inside the tyre's cavity or within the tyre's structure?
I need to insert a conductive metal filament, or pin within the tyre structure, under the elevated section of the tread. So if you look at a tyre from the inside, you would see a small plastic control box mounted flush against the inside wall of a tire.(Opposite of exterior tread surface). Protruding from the top of the control box, would be the metal conductive filaments or pins going inside the rubber, and reaching a depth of about 1/16 inch from the bottom of the tread base. So when the tire tread wears down it will eventually expose the conductive tip of the metal filaments. That will trigger an indicator showing a worn tire.
The shape of the pin could possibly be a U-shaped pin with the base on top (that is an inverted "U") and the bottom ends would be flush with the inner surface of the tyre. The U shape would almost look like two "I" letters, connected at the top.
What I am actually asking is for a tool or method to introduce such a pin into the tyre. I hope my description is clear. Please feel free to ask for more clarifications.
So what you are asking for is a method for producing a self-puncturing tyre. This is the logical conclusion of your description above, because when the tyre wears down close to the level of the pin, there will already be a tunnel along which air can pass from the inside of the tyre. (Tyre treads are not designed to be the world's greatest barrier to air; that's the innerliner's job.)
Any metal pin introduced in this way would also need to be brass plated to allow a bond to form between the metal of the pin and the rubber. Next the pin must pass through textile and steel cords without damaging the cords or the pin. Finally, such an installation, even though it would be very light weight, could possibly cause problems with the static and dynamic balance and the radial run out and radial force harmonics within the tyre.
How do you propose for the signal from the control box to be carried to the indicator lights?
Thanks for the valuable info. I kind of knew that this approach was a longshot. I was trying to find a different way of introducing the pin other than having the pin inserted during the tyre molding process. The latter approach requires the collaboration of the tyre manufacturer. Can you suggest any other approach?
Sorry, no. There have been many attempts over the years to identify when a tread has worn down to the legal limit but nothing beats visually inspecting the tyres regularly. Some coins (e.g. the UK's 2p piece) have a ring of dots around the faces circumferences. The distance between the inside edge of these dots and the outside diameter of the coin is approximately 2mm. If you locate the tread wear indices in the grooves and stand the coin on these, this gives you an instant visual check on the remaining tread depth. If you can see any part of the ring of dots, it's time to change the tyre (assuming the legal limit is 1.6mm tread remaining that is).
