Sor forgive my ignorance as I try to understand the angular contact points being made in above two posts. Is the point of the bold text piece of the [MENTION=507890]seb1466[/MENTION] post that I can use AC bearings with cranks that don't have mechanical preload adjustment, because as [MENTION=419049]WizardOfBoz[/MENTION] points out, preload needs are minimal anyway and AC bearings are tolerant of misalignments, but I will lose the advantage that AC bearings offer in terms of higher load ratings? I am running a pristine 80s Suntour BB on my Paramount and am perfectly comfortable adjusting preload via the adjustable cup because I can feel changes in spindle play and ball bearing movement. With my SRAM cranks, there is no such mechanical adjuster (There is an adjusting collar but I can’t say that it effects bearing load in any way).
My comments were aimed at comparing cartridge bearings ACBB or DGBB of equivalent dimensions. The cup and cone style bearings are a slightly different proposition but in my experience whether in hubs or bottom brackets they are all adjusted via screw threads to the point of minimum play. The point I was making is still the same; that mechanical adjustment means that the contact angle is fairly well fixed unless you set it with too much clearance. However if you preload with a spring system - as many bottom brackets that use cartridge bearings do - then the contact angle changes under loading. In this case a DGBB is a better option than an ACBB because there is less variation (e.g. in the case of a BB30 bottom bracket).