My one is Altezza RS 200. Tyre size 215/45, R 17. Since the tyre pressure affects the economy, what is the ideal tyre pressure. I am using 32. Earlier I was using 37. Some internet sources telling that is the ideal pressure. However, my mechanic told better to use 32 in rough roads like Srilanka. Because, car will vibrate more in high pressure and it will loosen the bolts and nuts. Low pressure is comfortable and good for car with the expense of fuel economy and tyre wearing. Can anybody advice me on that.