Not sure what's going on but three tubes burst on me today - the bike was stationary. Two tubes in the rear and one tube up front. Last week I swapped the wheels from my Batavus to my Fuji to compare the weight difference. The tubes and tires that were on the Fuji were transferred to the borrowed wheelset. I swapped the wheels back to the Batavus today, reinstalling the tubes and tires that were on them before. While I was installing the rear wheel back on the Batavus, the tube/tire started to expand and bulge at one spot on the rim until it explodes. The carnage that was left on the tube was a long slice approximately 6 inches long. I install a second tube and the same exact thing happens, leaving a similar slice on replacement tube. Fast forward three hours later...I'm in my home office and a third explosion. This time the front tube! Odd that it was delayed. I've checked both tires and rims and everything seems fine to my eyes. Any idea what may be causing this?? Sun M13II rims and Panaracer Pasela PT tires. Kenda tubes.