A flat tire doesn't always mean that you need to buy a brand new tire. Small punctures and damages are often repairable, which means your tire may still have several years of service life left in it. Several factors impact the ability of your tire shop to make a flat repair, so an assessment of the damage is necessary before making the decision to repair or replace. 

1. Puncture Location

Tires can only be repaired if the puncture is within the road contact zone of the tread. This means that punctures on the part of the tire that comes in contact of the road, which is the main tread beginning about half an inch in from each side, are typically repairable. Those on the edges or sidewalls of the tire can't be repaired, as these areas are more prone to bulging and blow outs once damage has occurred. 

2. Damage Size

The size of the puncture also impacts the ability to repair a tire. As a general rule, the smaller the puncture the more likely that the tire can be fixed. Long gashes, for example, can't be repaired as they cut through the steel belts on a tire and compromise overall integrity. Punctures that are less than 1/4 inch in size, which is average for common causes like nails on the road, are repairable. 

3. Previous Repairs

If your tire has had puncture repairs in the past, then these repairs can impact the ability to patch a new puncture. Generally, a tire can be repaired as long as the puncture is in a different location so that the repairs don't overlap. There are exceptions, of course. For tires that have had multiple puncture repairs, a new repair may not be recommended even if the old patches don't overlap since the integrity of the tire has been compromised by excessive patching.

4. Overall Condition

Age and condition must be considered before patching a tire puncture. If your tires are approaching the end of their working life, have low tread, or are beginning to show cracks on the sidewall, then it doesn't make sense to invest in a repair when new tires will be needed soon anyway. Tires that have more than half of their tread and working life ahead of them make much more sense to repair. 

Contact a tire repair service or mechanic if you have damaged any of your tires to learn about your options.