Originally Posted by
ct-vt-trekker
We also had a 700x 25 Conti 4000 blow off the rim a few weeks ago. I think in our case I thought it was a defective tube because the tube was split about 9" to 12" long . The tube blow completely out of the rim adn wrapped around the cassette. We were able to come to a stop quickly but we did ride on the rim for a bit. But since you mentioned this I could have had a similar issue, unfortunatley I can't check our tire because I threw it away.
I switched back to 700 x 28 GP 4 seasons for the time being.
Thnaks for the info, I'll keep an eye on my Conti 4000s that we're still using on all of our single bikes.
That's what the tube always looks like after a blow-off. Which variant of the 4000? One possible theory is that the extra weight of a tandem causes the rim to wear the already thin rubber off the bead area, exposing the cloth, and leading to a blow-off. I'd be interested in the appearance of this bead area on your singles, if you wouldn't mind having a look.