For my wheel size, the tire price for the 2nds ranged from RM50 - RM80 and new ones were from RM175 - RM 280. Though I was tempted to go for the low priced 2nds, I did not want to take risk, so I went for new (Goodyear) tires. While fixing, I decided to hang around and see what they did. They took out wheels from the car > removed worn out tires > fitted with new tire > did balancing > fitted back the wheels to the car > aligned. Well, that was routine stuff. Half way through this process, what attracted me was the guy who was busy doing something to an old tire.
Out of curiosity I asked him in my broken Malay 'apa ithu'. But he managed to reply in broken English, 'do 2nd hand tire!'. He was shredding rubber from worn out treads! I'm sure the tire was not tested for any belt defects, so am pretty sure that the strength of the tire is gone by doing this kind of patch work. Hardly he took about 10 minutes and converted a bald tire to 60% used tire!!! I was shocked & said, 'this is not safe', and he merely grinned. When I focused my mobile phone to take a picture, he requested me not to capture, but then I assured him that I wouldn't capture his face.
Moral of the story, DO NOT FALL for 2nd or used tires, even if someone tells you there is 60% or 70% tread in it.