Helmet
Fashion trendsetters make their mark by setting themselves apart. But when it comes to wearing a helmet, the split is pretty straightforward: You got one on or you don't. The latter group will likely continue to tempt fate till they crack their head open, while the former lot, already blessed with the wisdom to protect their cranium, can instead focus on the struggle of merging aesthetics and function. Giro's Xen ($159; www.giro.com) should simplify that quandary. This sleek, sly helmet rids itself of the bulky back end typical of most mountain-bike lids in favor of the style and deep coverage of a skate-style helmet. This aesthetic inspiration is matched by an "in-mold hardbody" construction that fuses the exterior shell with the interior liner for optimal protection, as well as 17 vents that had me flashing back to that wind-in-my-hair sensation I first felt when I learned to ride (for the record, this was the pre-helmet world of the mid-'70s). The price tag may be a tad high for some, but remember—it's your head. It also weighs a feathery 10.5 ounces and comes with a slick, no-rattle visor with 15 degrees of play.

Femme cyclists, however, shouldn't feel overwhelmed by the sheer ruggedness encountered in helmet-land. Specialized has merged the hardcore attributes you need in a lid without sticking to the ür-male aesthetic. The '04 Air Force ($35; www.specialized.com) helmet merges the woman's fit of the company's F.O.R.M. design, an in-mold sleek shape, and a visor with feminine colors and designs like frost and blue, purple with flowers, and pink (our tester opted for the flower motif, which she loved because "at first you can't even tell they're flowers") for that assured yet subtle, I am woman distinction.

Hydration Packs
When it comes to packs, flexibility is key—too much room and your backpack becomes a pendulum, too little and you cut a Supersize Me silhouette. CamelBak offers an ingenious solution that lets you have the best of both worlds. Their Blowfish ($90; www.camelbak.com) has all the trademark CamelBak includes—a robust 100-ounce bladder sheathed in an insulated sleeve, a quick-flow drink valve with leak-proof shut-off, a ventilated back panel, sternum and waist straps, a small zippered pocket with a key clip and mesh pockets—along with a large central compartment with a clever expandable pocket. Need more space? Pull the zipper and voila, the storage capacity increases from 749 to 890 cubic inches. Need to compress the pack now that you've donned another layer? Zip the baffled compartment back up and you return to the mini-Blowfish mode. Its narrow profile does mean you can't fit in legal-sized folders, so if you need a go-to commuter pack, you may want to upgrade to larger storage capacity. But the Blowfish will suit most city-to-trail outings, especially for the space conscious who like to pack it all, and pack it well.

The Hydrapac Ammo ($90; www.hydrapak.com) stands at the other end of the spectrum—a cavernous sack with zippered pockets (side, top, bottom) and compression straps galore, a front flap, a lower tool compartment, a 100-ounce bladder, a cell phone pocket on the shoulder strap, a neoprene-insulated drink tube with a Velcro sleeve to keep it from flapping while cycling, and enough room to pack your laptop and a pair of shoes…even the removable waist strap has a mini-pocket for loose change. And we're happy to report that the bag's interior stayed dry after a sudden mid-August downpour caught a fellow commuter midway between home and office. Alas our cyclist was not so lucky.

Sunglasses
Given the D.C. locale embraced by our gear test group, the name of Smith Optic's District Slider ($129; www.smithsport.com) already made it a lead candidate—but these slightly oversized polarized shades have more going for them than just lexical coincidence. The full-on sport-specific functions you demand in performance eyewear—lightweight, distortion-free, 100-percent UV protection, and a no-slip rubber bridge—are disguised in a hip wrap-around frame with expansive lens cover. As with all glasses in Smith's Slider Series, the District comes with four (yes, four) interchangeable lenses that easily glide in and out just in front of the hinges. Slide in the orange lenses for shaded trail bashing, replace 'em with a hipper shade of black for post-ride patio drinks, then opt in the clear lenses for a debris-free, dusk-lit ride home. And despite its large lenses, fogging has never been an issue, even in the swampland humidity of August in the nation's capital.

For those urbanities more in synch with Lance than Bono, trust in the optical wisdom of Bollé. As the slew of Bollé-donned Summer Olympics stars aptly demonstrated this August, the optical company offers a wide array of performance eyewear, from the slope-side-slick Metal Series to a variety of sport-specific optics. But our testers were continually drawn to the Snake Series, which offers durable plastic frames with "Thermogrip" no-slide nose pads and a wrap-around styling and just the right hint of urban chic. The Sizzle ($100; www.bolle.com) is ideal for on- and off-trail satisfaction. Its springy frames feature rubber at the ears for a tight, comfortable fit and come in a variety of different frame and poly-lens colors to make your pair as distinct as your dress code. One caveat—if you get a polarized pair (and you'll want to) Bollé does like to advertise that fact by printing the word on the upper corner of the left lens. Fine for most people, but the detail-obsessed may get distracted by the inverted words in their peripheral scope.

Gloves
The new el Moro Glove ($49.99; www.pearlizumi.com) from Pearl Izumi has joined full-hand coverage and the fingerless mitt by lacing lightweight stretch mesh between the fingers for a cool flow and optimal fit, along with a perforated palm for both durability and breathability. Non-slip fingertip patches offer solid control of the gears and handlebars, the Velcro-attached neoprene cuff wraps snugly around the wrists without crimping, and the thumb-lined microfleece offers that much-needed wiping surface for August sweat or late-October sniffles. And, as with all Pearl Izumi gloves, the el Moros come in sizes specific to both men and women.