Hey all, starting to get back into cycling after having a running spree last summer. So I went out on my first ride in awhile and 8 miles in I noticed this happen. What usually causes these?

Defective tire......Take it back if you can.

Only God is powerful enough to make something freakish like that happen.

Alternatively, a defective tire. Did it happen suddenly or over time? And deflate that thing before it blows up in your face.

It happened suddenly. The more I think about it, the more I realize that my tyres are probably just worn out, I think these ones were around before the wheel was even invented. Tubes are new, but I've had those tyres on forever.

Yes, get a new tire.

that happens when the cloth casing of the tire is compromised enough for the tube to push through into the rubber of the tread... that tire is a goner.

I would say that you could buy high quality tires with fine casing threads but really just having a decent tire that isn't rotted and dry will be fine.

Yeah, that's gotta be a hole in the casing.

That's a goiter. It's caused by an iodine deficiency.

Sorry to bump this old thread, but I've struggled all round the net looking for something similar.
will something like this eventually lead to a blowout?

I picked up a 2012 Giant Defy 5 about 6 weeks ago, and had a blowout after about 120miles on the front tyre. Admittedly I hit a (genuinely small) pothole just before, but then heard a clicking noise of something going round the wheel. I stopped as quick as i could but it 'banged' before i could stop, basically just leaving a tear in the tyre and inner tube. Having hit the pothole, i assumed it was my fault, and 'one of those things'.

I replaced the tyre with a continental Gatorshell. Went out this weekend, and 35miles in (about 170-200miles on the tyre) on the other wheel (Giant standard tyre), i started hearing the clicking noise. Stopped, and found a bump like this that was running against the frame on each revolution.

Being 15miles from home, and not wanting to annoy the missus, i tried taking it apart on the road side to look at it. The point initially flexxed and felt like stretched rubber, but between deflating, and taking the wheel and tyre off, the bump totally disappeared. I re-inflated using CO2, but hadn't properly seated the tube. Eventually got a lift, and once at home re-seated, inflated to 100psi (120psi recommended) and no bubble. The reason I stopped was that i heard a 'twang' noise.

Anyway, leading back to my original question, if i can replicate the bubble, i'll take the tyre back to Giant. If this will eventually lead to a blowout like my first one, i'll take the other ripped tyre back as well and ask them to replace both.

Thanks for any help.
Rich

Replace that rear tire as soon as possible, if not sooner. The casing cords must be damaged and you managed to slip them back over the void but it's only temporary.