There is an ample number of options available, as you are looking for a small car like a hatchback, follow the below link - Cars. For a perfect car choice, a comparison is to be done on the basis of price, size, space, mileage, performance, features, and other specs. Moreover, you may have a test drive of the shortlisted cars for a better idea of comfort and drive quality by visiting the nearest dealer in your city. You can click on the following link to see the details of the nearest dealership and selecting your city accordingly - Dealers.
In order to improve the mileage, we would suggest you drive slower. Driving fast can reduce your fuel efficiency by up to 33% if you are travelling above 60 mph. It is best to change gears appropriately and match the gear and the RPM carefully.
The main reason your spare tire is smaller is that they are meant to take up less space in your vehicle. The spares usually have a smaller diameter, narrower width, and shallower tread, which means they make great space-savers. This is especially important to maximize the storage area in your boot.