1. That's not double the air; it's double the air pressure. PSI is how hard the air is squeezed in; it is not the amount of air. Because a spare tire is much smaller, it actually has less air, not more.
2. It's made differently (thicker or different materials), so that it can withstand more pressure.
Pressure requirements have nothing to do with construction of the tire. It DOES have to do with the fact that it's a smaller tire. PSI stands for "pounds per square inch".
Think of it this way: the tire is smaller and has quite a bit less surface area in contact with the road. Thus to support the same weight over a smaller surface area, you need higher pressure. More pounds for every square inch of contact surface.
Make sense?
As for why it doesn't blow up, that does have to do with the construction of the tire. Same reason why tractor trailer tires don't explode when they are usually inflated to 100-120 PSI.
Simple.
What does the air in a tire do? It supports the weight of the vehicle, yes? A tire really is just a fancy container for air.
If you have a big tire with a large air chamber it can support a lot of weight at lower inflation pressures than a small tire with a small air chamber. Thus on the smaller tire you have to compensate by using higher inflation pressures.
The spare tire may have been engineered to withstand higher air pressure for safe usage and to compensate for its small size relative to the normal ones, since most spare tires are only meant to be used temporarily and at speeds of less than 60mph. Also, all tires including spares should be inflated, not to the maximum air pressure indicated on the sidewall, but to the vehicle-specific air pressure recommendation indicated in the car's owner manual.
The space saver spare has a smaller contact patch (the portion that's in contact with the road). In order to support the same weight as the original tire with a larger contact patch, it must have a higher pressure.
space saver spare. It's a temporary spare and a different construction than a standard tire.
spare tyre is way smaller than any normal car tyre but how & why does it take 60pis...why does it not blow up cause the 60pis is roughly double of air of normal tyre takes
