Just noticed a spot on my rear tire (Gatorskins) about an inch long where the kevlar material is showing through. I've probably ridden it that way for the last couple of commutes at least and didn't notice.

I changed it, but I wondered how long I coudl have gotten away with it. It felt pretty tough there.

So are you usually changing your tires as soon as you see some thread/material showing? Sooner? Or do you wait and get every last mile out of it?

Sooner, but definitely by the time you see casing or flat prevention fabric. I'll usually run a tire until I get what I consider two non-freak flats within a couple weeks or so.

I wait til threads show.

nothing like living on the edge. just depends on how lucky you feel with regard to flats. if you have never had one.... if you get them all the time..... me? I replace before threads start showing up. hate flats.

Usually when I happen to see the thread on my any of my bikes' tires, it' from a a laceration or the tread has separated from the casing, either way, the tire gets replaced. I have yet to wear a tire down to the cords.

I haven't had many flats in my life, but I do change my tires often. Maybe there's a correlation there. I use folding tires, so the old ones can be refolded and brought on long trips in case I have a sidewall blowout.

Once the threads show, you're not far from having the inner tube bulge through. I've had that happen once when I noticed that the bike was bouncing up and down the downhills. I stopped to find out what was wrong with the back wheel and discovered it. If you feel really, really lucky you can keep going until you're riding on the bare inner tube, but I would change the tire as soon as the threads show.

I change tires when I start getting flats

Do you have a braking problem that causes the wheel to stop in the same place?

It may be slightly wasteful, but I change tires once the tread area is noticeably thinner. Not only does it make you safe from blow-outs, but avoid many of those annoying flats too.

I only wait for threads on the front tires.....

I don't wait for threads to show.I go through about 4 tires a year.When the back wears out,the front goes on the back and a new tire goes in front.

+1, appearance be darned if it works it works (and if it doesn't it doesn't)

I would definitely change a tire if the threads were showing through. I generally start getting more frequent flats when the tread gets thin on my tires and it's not worth it trying to squeeze out a few more miles.

I've never seen any correlation with flats and tire life. If I'd used that criteria, I would have pitched a Gatorskin in the first year, which in fact lasted me two years, with no flats at all in the second year. I pitched it when the cord pattern started showing through the tread.

Another vote for changing tires when flats become an issue. Worked for me so far.

I knew I was getting thin on my gatorskins - cause the profile of the tire was wide, flat and bald. Not sure how many miles I rode with the bare spot - more than a couple - and no flats. I think this tire lasted about 2.5k miles, maybe a bit more -- and had only one flat in that time - pinch flat from hitting a pothole. THe tire had many small cuts in it -- about 1/16 to 1/8 of an inch - where you could bend it and see the kevlar material. Apparnelty they do a good job with puncture protection.

I replaced it with a cheaper Forte (performance brand) kevlar belted tire just because I had it on hand. It rode beautifully this morning -- we'll see how it does with flats and longevity.

Me too, I change long before a thread shows through. I'm allergic to flats,I break out in really embarassing obscenities.

Marc

I replace mine before threads show up, because all the trash and rocks I commute through leave the tread pretty torn up. I replaced my rear tire when the tube started pushing through a particularly large gash left by a puncture... couldn't see it unless the tire was inflated all the way. Now that I'm using Mr Tuffy liners, it helps, but I'm still replacing them after only about 3K miles (they're very cheap tires).

I've been keeping a record of my flats and tracking number of miles, which tire, weather conditions, location and time of year. The pattern that has emerged is that most of my flats come on the rear tire (obviously) when it's wet (obviously) on roads with bike lanes (less obvious but certainly true) and the tire has more than 2000 miles. My only hesitation to nail the mileage down as a hard indicator is that I have historically been hitting 2000 miles on a tire at about the same time each year (early spring) and so there could be something like increased road construction that factors in. This year I changed tires mid-winter and had less than 1000 miles on my rain tires in the spring and my only flat was on another tire (Michelin Country Rock) with no special flat protection system (but only 270 miles at the time).

Tires with more mileage are more susceptible to flats. They are thinner and (depending on how well one checks and cleans tires) there may more be residual material still emedded in the rubber that can work its way thru. To add some pure speculation the older rubber may also be less resistant to debris.
I've ridden centuries with rear tire threads showing, but if going for a long ride I would prefer to start wtih a fresher tire so as to reduce the chance of a flat.
Some tires (notably GP4000S) I've used until threads show (and usually thin flat bits of rubber start to peel away) with no flats the entire ~4.5k mi life of tire.

Some tires seem to have multiple layers of different kinds of rubber. I've seen a couple that apparently had a tough outer coat, and a softer inside. When they wore down to the soft stuff, they seemed to trap stuff from the road, which then got through and flatted the tube. Similarly, the Vittoria Randonneurs had an inner red rubber; when you see the red, it's probably because you've neglected the tire until you've had a flat, and more are coming unless you replace the tire ASAP.

^ This. One flat means nothing, but another (non freak) one within a week or so an' it's new tire time

There's something very beautiful about new tires

No,But I am also very heavy handed,and would never admit to that either

One large skid could have done it.

You reached the point where I get a new tire.

Do you change your cycling shorts if skin shows thru?