It is simply not true to say cheaper tyres give worse mileage, some will give better mileage as they contain more carbon black. The more carbon black in the tyre the harder the rubber compound is and the better it will wear. So a cheap tyre will tend to have a large block pattern to make up for a poor contact patch design, but in order for the blocks not to be too flexible the rubber must be quite hard. Again, and as said before, this can cause some under-steer if your an enthusiastic driver. Under-steer: When the front of the car hits the fence Over-steer: When the back end of the car hits the fence Momentum: How far you end up in the field after going through the fence Torque: How far you drag the fence with you after you have hit it and carry on down the road Tyres are important, but more importantly is to buy tyres to suit your driving, or drive to suit your tyres. I drive a whole lot of different vehicles in a week and have no control over the tyres that are fitted, and I last had an accident over twenty years ago. And even that was not down to poor tyres, it was down to a poor decision on the part of a third party.