Tandem Cycling - Blowout

We had our first flat yesterday in 2 years of tandem cycling, and it came in the form of a blowout. We were on a flat, even road, going around 16mph. I heard a ticking from the back wheel, and as I slowed...BLAM!!! The tube blew out the side about 3 inches from the stem, and I can see where the rubber on the outside of the tire bead is slightly damaged. I hadn't replaced the tube recently, and I'm pretty sure the tire bead was properly seated. We're running Schwalbe Marathons on Salsa Del Gado Cross rims, both of which were new last fall, and we didn't ride much over the winter. I've been inflating the rear tire to 110 psi, and the front to 100, but I realize that the Schwalbes are only rated to 95. Could that have caused the blowout? BTW, our total weight is around 360 lbs. I'm just thankful that this didn't happen on a downhill!

Lazlo

I've been inflating the rear tire to 110 psi, and the front to 100, but I realize that the Schwalbes are only rated to 95. Could that have caused the blowout?

Not in my experience; more likely just some type of a bead seating issue.

But, that's a guess as I'd have to see a lot of pictures of the tube, tire, rim, etc. before even venturing a guess at the actual cause... and even then it might be hard to know. However, if you have the same rim / tires on the front of the bike you might want to deflate the tire and double check bead seat and bead to make sure you still have a tire that fits snuggly on the rim.

We have 26 x 1.5 Schwalbe Marathon Racers on our tandem rated to 85 psi. Our LBS mechanic, who does a lot of tandem work, has continually told us not to inflate past 90 psi. Over the last 19 years we have blown 3 or 4 rear tires, sometimes it just happens.

Every tire I have had over 1.5 inches wide has failed at the bead. Tires 1.5 inches last the longest they fail due to more than one cut hitting the same spot.

This was a 32mm tire. Thanks for the advice, I'll check my front tire, too. I'm taking the rim and tire to the wrench who built it to have it checked out. What made this even more fun was that I replaced the blown tube with what proved to be a poorly patched one, which then went flat 3 miles later. Luckily, my second spare tube was a new one. On the plus side, my wife got a roadside flat fixing lesson, and it was a nice sunny day.

Your first flat in 2 years . . . ?
But how many miles on that tire/tube?

Our last flat was about 2,260 miles (and 6 months) ago.
We run Maxxis Re-Fuse 700x25 tires.

Less than 500 miles on the tube and tire.