Nope, the Open Sport is a completely new rim. Unlike the MA3, the Open Sport is narrower, has a triple-chamber cross-section (MA3 was single chamber), and has sidewall wear indicators.cmg said:i thought these were a renaming of the Mavic MA3.
If you look closer, you'll see that that the internal cavities are shaped differently. This can be seen more clearly here: Open Sport cross section. As you can see, the two side cavities had to be re-shaped to accomodate the wear grooves. This requires completely new tooling (extrusion die). Also, as can be seen in the two photos you provided, when they re-designed the extrusion, they also made the spoke bed thicker (probably because of the high number of spoke hole cracks with the MA3). Although it may fill the same market niche, it is a completely new product.cmg said:both 490g. don't really look that different. the groove on the brake face is the wear indicator.
Well, there's no threading involved in the rim, but the Open Pro is socketted, whereas the Open Sport is simply eyeletted.Mr. Peabody said:The mechanic was explaining that on the Open Pro, the threads in the eyelets continued through the center channel to the other side, so that when the spoke was threaded in, it would have more surface contact, or threads, to bite into. I'm not quite sure what he was referring to, and hopefully someone can shed some light on this.