If your car is 100k km around, better see if timing belt has changed or not. If not get that changed FIRST.
Check the seals on exhaust manifold isn't leaking and making this loud noises.
If you mean tire has swollen from one side then its manufacturing defect and you should get free replacement. Check the tire manufacturer if they honor the warranty in this case. Usually all tire manufacture cover this in warranty and offer you free replacement.
Its truly depending on type of tires that you drive. Still groove has to be minimum 5 mm remaining on all around to be safe. If its lower or closer to this then better get new tires as its the only thing that touches the ground in whole car and has to be in top condition to drive safely.