The XD started out as a mountain triple but after a few years Sugino also released a double version. The XD "Track" is just a double with one ring.Tell the countless number of people who tour, fully loaded, using XD's that they are riding subpar cranks with too much flex and you'll probably get your ass handed to you by people who have a right to tell you that "you have no reason being on a bike". You're right that the price difference reflects more than just the "bling factor"(although the NJS certification certainly plays a big part in it!) but it has nothing to do with the flex you speak of - the 75's go through different forging, machining, and finishing processes than the XD's. I seriously doubt you can tell the difference unless you have the Six Million Dollar Man's legs. Granted chainring flex is more likely with a 110bcd but there's another even more likely possibility - While, AFAIK, this hasn't actually been proven, IMO what you're blaming on the crank is most likely actually the frame flexing. Think about it. A crank arm is a pretty stout piece of metal while your frame is a thin tube, steel or whatever it may be.Go back and read RichPugh's post. The XD2(the original XD was not) and 75(as well as the Grand Mighty) are cold forged while the RD is only labeled as forged, which could mean cold forged or maybe not. Why don't you go straight to the source? http://www.suginoltd.co.jp/contact_us_e.html