I agree with Eric. We see quite a number of rack and fender equipped bikes at the shop and many that have only one eyelet per side to use. Most have the fender braces inside the rack's. Most of these also have no large (yes, a "fender" washer) washer on both sides of the common "V" bent fender brace. So not only does the single bolt see the rack's vertical loads far from the eye (thus a bending instead of a shear stress) but the fender brace can open up and cause the bolt to not snug the rack up as much. I believe this is done because of a few reasons. First critical thinking and basic mechanical concepts are not well taught any longer in school. Second most can't or won't figure out how to bend the fender brace so it wraps around the rack brace on it's way to the top of the rear fender. And third is that bike accessory companies rarely work together to make more then their product fit well in many situations. A simple solution would be if rack manufactures included a fender eye behind and to the rear of their rear most brace. That Eclipse low rider rack I mentioned included this (yes on a front rack) way back in the late 1970s. But I suppose some rack brand's liability lawyer would not like this... Andy