What pressure are you pumping them up to and is the rim tape wide enough? The only thing I can think of, is that the tube is "ballooning" into the spoke hole and bursting.
That doesn't look like a penetration of the tube (by something sharp) and the dimple on the other side suggests the same thing is happening there too.
What pressure are you pumping them up to and is the rim tape wide enough? The only thing I can think of, is that the tube is "ballooning" into the spoke hole and bursting.
That doesn't look like a penetration of the tube (by something sharp) and the dimple on the other side suggests the same thing is happening there too.