I know what the issues of aligning aluminum rear triangles are but I am not aware if certain types of aluminum tubes are more safely cold set than others. What an optomist eh? I am working on a friend's Giant OCR Touring with Avid mechanical discs. Her OLD is 135 and the dropout spacing is 130. The triangle is aligned to within 1mm and the dropouts align precisely. I tried taking out an axle spacer but of course the rotor then rubbed on the caliper. Frame material is 6061 Aluxx Extra Light. I suppose she will just have to keep spreading the frame when inserting the wheel but I wonder if this repeated stressing is not worse than a one-time "fix".