Answer: Rubber source, temperature, thinkness, thread design, driving pattenrs, weather, etc.
Explanation: There are many variables. Here are a few I would include in a tire lifetime study:
1. Type of rubber, including source
2. Thickness of tire
3. Design of tire thread
4. Life as a function of average speed and road surface
5. Expected outside temperature and wet conditions
6. Driving conditions of speed and both acceleration and deceleration parameters (e.g., tire life when slamming on the brakes or accelerating quickly)
