When should you replace tires after getting a flat?

Question

A nail punctured my rear wheel tire today while riding. My question is, how do you know if you need to replace a tire or simply repair it with a tube repair kit?

The hole looks pretty nasty. The cap part of the nail entered the tire, leaving an L shaped hole.

My concern is that water might get into the wheel in wet conditions.

Answer 1

From personal experience, I'd say a larger-than-usual hole in the tire could have these undesireable side-effects:

1. The tube might get a bit exposed, and the day-to-day rolling over the hole might wear it down until the tire eventually flats out. Chemical aggresion from road grime or mud could also be involved.
2. The fabric of the tire might get damaged to the point there is a visible bulge. This not only causes a bump while rolling, but most importantly is a weak point that might lead to tire explosion and and accident.

Most of these somewhat larger punctures damage mainly the rubber and not so much the tire fabric (plies). If that is the case, a simple cautionary patch on the inside (with a regular tube patch) is enough to warrant peace of mind.

If the tire is bulging around the hole when it is inflated at the pressure you use, that is a warning indicating the tire is probably too damaged. A larger or stronger patch might be used inside the tire, and some regular observation to see if it stabilizes or grows is needed, but most probably it would be better to get it off the bike (which is very sad when it is a relatively new tire).

Hope this helps

Answer 2

Generally, if you are using an inner tube in the tire, you should replace the tire if there is more than a 2 millimeter cut in the tire casing. Not in the rubber, mind, but it the threaded cloth casing that you rubber bits are laid on to.

I personally err on the side of replacement rather than risking a serious injury from a blow out at a bad time, so I usually replace when there is a 1mm or larger cut in the casing.

Or if I put a new tube back in, and the hole is large enough to see the tube.

Answer 3

Generally, you repair tubes, not tires. From your last sentence, it sounds like you are indeed talking about the tire.

As it is with the tube, the real answer is "Size Matters". In this case, both the size of the hole and the size (okay, type) of the tire. If I was looking at damage to a road tire "slick", the hole you describe would likely having me change tires. On a cross or MTB tire I might try a repair. In addition to using a tube patch, I'd also glue the "L shaped hole" back together with superglue.

If there's any safety doubt, change tires. The closer to the side of the tire, the higher chance this could cause a lack of integrity while riding.

Never hurts to get a second opinion at your LBS either. Smaller shops will tend to give you a straight answer rather than just going for the sale of a new tire.

Ride Happy!

Answer 4

Always BEST to just replace the tire, but... I have ridden my tires with a gash of an inch or longer. I couldnt recommend it to everyone (legal issues) but I do it all the time. I take an old tube, cut about a 2 inch section out of it (so you have a 2 inch long tube, not just a patch), wrap duct tape around it then duct tape that onto the inside of the tire.

It will poke out the cut a little, but as long as you have a decent tire, your chords will keep it from ripping more.

Answer 5

I've never heard of repairing a bike tire. Maybe if it were tubeless you could plug it, just as you do on your car. But if not...I guess if you're just cruising around town give it a shot. If you are pushing the limits on this thing, buy a new tire. Worst case you blow out and slide under a truck (or into a tree maybe if we're talking mountain biking?). Best case you end up flatting over and over b/c the now non-smooth inner wall of your tire constantly wears down the tube. When inflated, tubes are very thin and very easily punctured or worn through. Dropping $50 on a decent tire might seem annoying, but if you hurt yourself riding on busted gear, you'll regret having 'saved' that money.