Tire wear patterns: what they mean
The way a tire wears tells a story about how it has been treated. Before you replace worn tires, it is worth looking at where the rubber went, because the same cause will wear out the new set too if nobody fixes it. Run your hand across the tread and look at it from the front of the car; most patterns are easy to spot once you know what to look for.
Wear on both outer edges
When both shoulders of the tread are worn down more than the middle, the tire has generally been running with too little air. An underinflated tire sags, so the edges carry more of the weight and scrub against the road. This pattern often builds slowly, because a tire can lose pressure a little at a time without looking flat.
Wear down the center
The opposite pattern, with the middle of the tread worn more than the edges, generally points to too much air. An overinflated tire bulges slightly in the center, so that strip does most of the work. It is a common result of filling tires to the maximum number printed on the sidewall instead of the pressure the vehicle maker recommends.
Wear on one edge, or a feathered feel
If only the inside or only the outside edge is wearing, or the tread blocks feel smooth when you run your hand one way and sharp the other way (called feathering), the cause is generally an alignment or suspension issue. The wheels are not pointing quite straight, so the tire is dragged slightly sideways as it rolls.
FlatFixVault does not do alignments. If you see this pattern, have the alignment checked at an alignment shop before new tires go on, so the new set does not wear the same way.
Cupped or scalloped patches
Patches of uneven wear spaced around the tire, sometimes called cupping or scalloping, generally point to worn suspension parts or a wheel that is out of balance. The tire is bouncing instead of staying in steady contact with the road, and each bounce scuffs a spot. You may also notice noise or vibration that changes with speed.
Find the cause before mounting new tires
Uneven wear is a reason to find out why before buying replacements. Some causes are quick to deal with at the tire shop: we can set the tires to the correct pressure for your vehicle and balance the wheels. Others, such as alignment or worn suspension parts, belong at a shop that does that work. Sorting out the cause first protects the money you are about to spend on tires.
If one tire is much more worn than the others, mention it when you call. It can change which tires make sense to replace and in what order.