Rubber with embedded steel wire is less stretchy than the rubber bands we're used to. Tires even more so than belts; it adds integrity like rebar in concrete.

Rubber with embedded steel wire is less stretchy than the rubber bands we're used to. Tires even more so than belts; it adds integrity like rebar in concrete. You're correct that once it jumps even 0.5cm (~1 tooth) it could touch piston to valve; it depends on the engine, but I'd wager most nowadays are interference.