Determining if tires on a 2013 Volkswagen Caddy are unsafe to use in Chengdu involves inspecting several key safety factors, starting with the tire's age. Most manufacturers recommend replacing tires every 6 to 10 years regardless of tread depth because rubber degrades and becomes brittle over time; therefore, tires from 2013 are likely over 10 years old and should be replaced to avoid failure. Additionally, you must check the tread depth; tires are considered unsafe when the tread is worn down to 2/32 of an inch (1.6 mm), which can be identified by built-in tread wear indicators or the penny test. Visual inspections are also crucial for spotting "dry rot" (cracking), bulges, or sidewall weathering, which are common in older tires and indicate a high risk of a blowout. Proper inflation is also vital, as the humid and variable climate in Chengdu can affect tire pressure; for a Volkswagen Caddy, you should typically maintain a pressure of around 36 psi (2.5 bar), though you should verify the exact specification on the driver's side door jamb or in the owner's manual. If the tires show signs of uneven wear, cracking, or are the original 2013 equipment, they are unsafe for continued use and should be replaced by a professional.