Websters Dictionary describes intentionality as "The quality of mental states (e.g., thoughts, beliefs, desires, hopes) that consists in their being directed toward some object or state of affairs". It's usually used in reference to a person, but I don't think it's only individuals that display a sense of intent; companies -- in this case rim manufacturers -- also convey intentionality, for better or for worse. When I work on a wheel built elsewhere, I can usually get a good idea of what the company was aiming for; I've seen 32 hole mountain bike wheels built with a 2 cross lacing to save weight, all held together by inferior 2000 series alloy nipples, once again to save weight. I've seen rims from well-regarded companies that are so flimsy that wheels suffer significant loss of spoke tension once the tires are mounted. All done in pursuit of low weight. I can only assume that these companies' sales are driven by favorable reviews in magazines (in which they just happen to advertise). Cynical, I know; but I suspect the intention is to sell a lot of product rather than selling good product.
Astral Cycling is a company whose rims I've used for a couple years now. Readers of my blog will know that I have a high regard for this Eugene, Oregon company. It's the sister company to Rolf Prima, manufacturers of paired spoke wheel sets, with the two companies housed under the same roof. While I'm not a proponent of the paired spoke wheel design, I do acknowledge a happy by-product of the link between the two companies. Paired spoke wheels like the Rolf demand a robust spoke bed to prevent pull through; having left and right spokes attached to the rim less than an inch from each other would play havoc with insubstantial rims. Here's the good stuff; Rolf and Astral use the SAME extrusions; the Astral Solstice is the Rolf Elan, the Astral Radiant is the Rolf Vigor, etc. Same super strong spoke bed, just with a different drilling arrangement. This results in giving Astral rims an extra margin of durability over the majority of conventionally drilled rims on the market.
I recently purchased a pair of Astral's new 27.5 Backbone alloy rim. The 30mm internal width accommodates tire widths up to 2.8 inches.
It's an asymmetrical rim where the spoke bed is pushed 2.5 mm to one side, resulting in close to even spoke tension between left and right side spokes; similar spoke bracing angles for driveside and non-driveside spokes results in wheels that steer and brake better. The rims are made from 6069 aluminum alloy rather than the more common 6061. Depending on design, a 6069 rim displays a tensile strength 40-65 percent greater than 6061; it's lighter than 6061 as well. At 23mm deep, the Backbone is a little taller than offerings from Velocity, RaceFace and Stan's No-Tubes.
How did they build up?
I wish all rims felt this good during the tensioning procedure. I laced the rims onto Bitex's excellent BX211 6-bolt 410 gram boost hub set. Bitex makes close to a million hubs per year, mostly with someone else's name on them; in 2011, they were THE first company to produce a 6 pawl freehub mechanism, thereby offering engagement every 3.3 degrees. The front hub is equipped with large 6903 cartridge bearings; the rear comes with two 6902 bearings in the main hub body and two 6802 bearings supporting the freehub.
Anyway, about the rims.They went from loose to tight to perfectly-tensioned in an orderly, progressive manner. As with all wheel builds, it was the usual juggling act of balancing trueness (both lateral and radial), tension and dish; but the rims never required that I double back on the procedure to put out a fire. Built with the aforementioned hubs and 64 Wheelsmith double butted 14 gauge spokes and brass nipples, total weight came in at 1812 grams.
So, back to intentionality; if I had to discern what the Backbone is all about just by working with it, I would put it this way. Astral has aimed to make a rim that's light, but not too light, that benefits from modern design, such as asymmetric profile, and wisely employed a superior alloy that can take the knocks and hard use in this rim's future. They intend for the rim to succeed on good ol' word of mouth instead of gimmicks.That's how it feels to this wheel builder.
Thanks. I'll take it.