Many things to consider for FC. But since you only mention between tyre size, weight and diameter, here is mt 2 sens worth.
Changing from 175/70R13 to 175/65/R14, there is no change in tyre width, therefore road surface contact friction does not come into play, but however the tyre diameter have gone bigger by 1.36%. If you are comparing traveling at 80kph to 100 kph constant speed then the larger diameter will not have much effect, but if you are driving mostly in town on a stop/go traffic then the larger diameter will require more force to turn initially and this will need more fuel to move it.
Normally when we mention upgrade to bigger rims, yes we reduce the tyre aspect ratio to get the closest diameter to the original size, and at the same time it is for safety and handling. Safety in getting wider tyres and handling as in lower profile. Having said that another size suitable for your use is the 185/60/R14 size, which is closer to your original diameter......
Changing from 175/70R13 to 175/65/R14, there is no change in tyre width, therefore road surface contact friction does not come into play, but however the tyre diameter have gone bigger by 1.36%. If you are comparing traveling at 80kph to 100 kph constant speed then the larger diameter will not have much effect, but if you are driving mostly in town on a stop/go traffic then the larger diameter will require more force to turn initially and this will need more fuel to move it.
Normally when we mention upgrade to bigger rims, yes we reduce the tyre aspect ratio to get the closest diameter to the original size, and at the same time it is for safety and handling. Safety in getting wider tyres and handling as in lower profile. Having said that another size suitable for your use is the 185/60/R14 size, which is closer to your original diameter......