You guys are both wrong: http://www.bikerumor.com/2012/05/31/201 ... r-options/" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;

The rims are all wider, but you're right in that the 24's don't get Optibal, however, the wide rim is nice.

"Across the range, they’ve made the rims wider for better comfort and performance."

"They also used offset spoke holes on the rims, so spoke triangulation actually improves without any frame clearance issues. The OptBal 2:1 lacing uses this to give balanced overall tension between the two sides of the wheel – non-drive spokes are pulling twice as hard, but there’s half as many of them.

I have access to the ShimanoTec site as I'm certified by them to the highest level. Everything internally

The new rims are called D2 and are 23mm or 24mm wide depending on the wheel model. They also gave them a deeper tire bed so the tire sits more flush with the sidewall and there’s no gap on the clinchers"