Sometimes a tire can't be patched
While you may be tempted to plug a hole in a damaged tire, the risks aren't always worth it
No one wants to spend money on replacing a tire when they think it can be cheaply and effectively repaired.
But even with all the advancements in tire design and manufacture, those critical rubber boots on our rides are still prone to road hazards that can leave them in an unserviceable condition.
Simple, small punctures in the tire's tread face can often be repaired successfully, but how they are fixed can be crucial. The use of a rope plug, applied from the outside of an inflated tire, is a common DIY repair, but it's full of risks. Before this type of plug can be inserted, the hole often has to be enlarged with a roughedged, rasp-type probe.
The problem is the support cords/wires/belts under the tread can be inadvertently broken, leading to a weakness that may develop into a bulge or a belt shift.
The proper method of repair involves dismounting
the tire and installing a correct plug or patch from the inside. This gives the person doing the repair a clear view of the damage and the ability to minimize cord breakage
when reaming the hole. Punctures in the side walls of tires really can't be fixed.
Side walls do a lot of flexing during their daily travels, and this means their construction
isn't as robust as the tread face. When a proper inner patch is added, this flexing can weaken the air seal between the patch and the inner wall of the tire, causing the leak to continue. And plugs are out, because inserting any type of plug will most likely result in a bulge and/or blow out.
Impacts from hitting a pothole that don't immediately cause an air leak can still be ticking time bombs.
Hit a pothole hard enough, or at the right angle, and you can permanently damage a tire and its rim. Sometimes it can cause a flat, not because of a puncture but because the rim's bead edge was bent from the impact.
Most damage like this can be repaired on steel or alloy rims at wheel shops, and it's best to leave this type of job to the pros.
If a rim was hit hard enough to curl its edge, it will likely be severely out of balance and need to be set straight again to avoid vibration.
In cases like these, the tire should be suspect, even though it may appear undamaged.
Supporting and underlying cords can be damaged without any visual surface hints of the trouble below.
They often won't show their weakened state until they're back on the road at higher speeds.
And that's definitely when you don't want a flat tire.