RACER

RACER

RACER

mikegarrison

That depends on the tire. It's generally true for most street tires, but some street tires seem to have much more consistent grip levels through their life than other street tires do.

(Track tires are an entirely different animal.)

AssassinJN

This also depends on the type of tire and how low you are talking about. New tires (especially all weather or all season, the more tread the more true) suffer from tread squirm meaning that the deeper tread grooves make the rubber less stable (easier to bend from side to side) and also reduces responsiveness. This decreases grip while turning. It's common for auto-x drivers to buy old used tires that no longer provide great wet weather grip, but have increased dry grip properties.

Now if you are actually getting to the core or the wear bands, then that material is harder to prevent the tire from blowing before you're able to get them replaced. I am sure you've at least heard about serious racers shaving their tires to get the optimum contact patch and responsiveness from the tires. This is similar, but much better than worn down tires. While worn tires do have the same advantages, they are in a much more limited fashion. As tires heat up (every time you drive) there are agents in the tires that chemically bond the rubber together creating a layer of harder, denser rubber there by losing some of the grip benefits.

MechaGodzilla

Lower profile rear tires at higher pressure (and maybe heavier) make the rear shocks work harder.

The rear shocks can lose a lot of their performance with age and very little mileage (like five years and 30k miles). Once this happens the car will bump steer like crazy.

If you have lowering springs, the effect is even worse because of the rear toe control geometry.

MG