Over the past several years now, rims have been slowly getting wider and wider, but apparently that's not good enough for Ibis. While most of the industry is making small, incremental changes, Ibis has come in offering a rim with an astounding 35-millimeter internal width. Wider rims create better tire stability, allowing for reduced air pressures and a better contact patch without all the squirm normally involved. This isn't a new idea. Some of the earliest mountain-bike rims were wider than current standards. If you look at road bike and automobile tire-to-rim width ratios, they're far different from those of mountain bikes. Weight is the culprit here, but carbon construction allows for optimum width targets to be met within acceptable weight goals. Running a 2.35 tire on Ibis' new 35-millimeter rim brings the inner rim width to outer sidewall width ratio back to where it was in the 80s.
Another highlight is the lack of a bead hook on the rim. This is something that Specialized pioneered a couple years ago with its bead-less carbon wheels. We've tested the Speci hoops extensively and are convinced on the design. The hookless shape allows for a thicker, square-shaped rim wall, creating far better impact resistance–a wonderful thing when you're talking carbon.
Ibis is offering three wheelsets, each in two widths. The 650b, 741 and 29er, 941 will sport the 35-millimeter rim (Ibis refers to the outer width, which is 41 millimeters). The 928 will be a narrower, 22-millimeter inner width wheel, available in 29er only. All three wheels will be built with Ibis-sourced hubs and Pillar triple butted spokes for $1,300, or a modest upgrade fee on new Ibis build kits. Available in June. Expect ride impressions soon.