Joined: Feb 2012
Posts: 19,320
Likes: 5,429
From: Rochester, NY
Bikes: Stewart S&S coupled sport tourer, Stewart Sunday light, Stewart Commuting, Stewart Touring, Co Motion Tandem, Stewart 3-Spd, Stewart Track, Fuji Finest, Mongoose Tomac ATB, GT Bravado ATB, JCP Folder, Stewart 650B ATB
To my eye these cracks are not typical to Alu bikes. Esp. the LH stay one. The mid tube location and the crack running lengthwise suggests that the stays may have been made from strip (as in seamed tubes) and you're now seeing the weld stress cracking the stay open. I would suspect the remaining of the stays. Andy.