If your tire pressure is low then it can cause uneven wear on your tires. That means that one tire may wear faster than another forcing you to have to replace all of your tires sooner. This can be quite costly. Low tire pressure also puts you at risk of popping your tire sooner. When you drive down the highway you may also feel your vehicle pulling to one side of the road because of this. Also low tire pressure forces your vehicle to use more power to generate the same amount of speed, costing you more gas and money!