Reviewed: Specialized Mountain Bib Short Liner with SWAT

Specialized wants to let you mountain bike in a baggy, pocketless jersey without a hydration pack but still carry your essentials, like a phone or a bit of food, so it created the Mountain Bib Short Liner to let you do just that.

I don’t enjoy taking a hydration pack with me on mountain bike rides. They’re clunky, and, coming from a road background, I like to keep weight off my shoulders; I need every bit of arm strength for airing the double, or at least that’s what I tell myself. In the development of its new SWAT bib short liner, which sits inside a pair of baggy shorts for that casual-but-comfortable look, Specialized clothing designers had a similar train of thought. They may have applied a few extra bits of marketing jargon to the concept — “a tighter center of gravity,” for example — but the idea is the same: take the weight off your upper back and bring it as close to the hips as possible by adding storage to the bib liner itself.

It feels odd to write a review claiming that a pair of mountain bike short liners is a revelation, and possibly my favorite new product. But they are, and let me tell you why.

The SWAT line from Specialized was launched last summer. SWAT stands for storage, water, air, tools, and is Specialized’s buzzword for ditching your hydration pack, bento box, and other unsightly accessories. The SWAT clothing system centers around these bib short liners, regular (non-bib) short liners, and a baselayer — all with pockets, so you don’t have to wear a road jersey over it.

Good baggy liners are rare. More often than not, I rip the short liner out of a new pair of baggies and introduce it to the nearest trash receptacle. I prefer to wear bib shorts, but until now, finding a pair of baggies that came with a bib short liner that I’d prefer over any of my road bibs was impossible.

The Mountain Bib Liner with SWAT comes as part of the new Specialized Atlas XC Pro shorts for $150, while the Mountain Bib Liners sell on their own for $88. The new Atlas XC line is part of the three-tier mountain bike apparel offering from Specialized, which also includes the Enduro all-mountain line and the Demo gravity line.

The Mountain Bib Liner with SWAT has three rear pockets, much like what you would expect to find on a road jersey, but the pockets are built on a flap that won’t push down your baggies. Instead the pocket flap is not attached at the bottom, so it can hang over the waistband or your baggies. The Bib Liners also have two stash pockets that hold tight to the side of the leg, like where an actual SWAT officer would holster a sidearm. Specialized athlete Matty Hunter prefers to use these pockets to stash his phone. We would recommend running an Otterbox Preserver waterproof case if you go this route, or risk sweat damage to your electronics.

For those who don’t like bib shorts — odds are you stopped reading long before now — Specialized is also making a bib-free Mountain Short liner with SWAT and vest liner.

The Bib Liners are not without their quirks. Loading up the pockets can take some getting used to. Retrieving items is far easier than getting them back into their respective pockets. Jerseys tend to get snagged on bottles when you reload them into your pocket. The system is not as simple to utilize as a road jersey.

So that brings up the topic of the Mountain Bib Liner’s largest competitor: the pocketed road jersey. It’s functional, with easily accessed pockets, and performs well, designed to wick sweat.

But it’s also not very cool. The greatest factor in the push for baggy jerseys, the one that saw surfers wearing their board shorts on mountain bikes in the 1980s, is fashion. Riders don’t want to wear lycra on the trail. A Castelli Body Paint kit is not at home on a 6” travel mountain bike. But baggy jerseys don’t do pockets well, or at all, so you need something else to stash your stuff. Enter Mountain Bib Liners.

The Mountain Bib’s other competitor might be the Giro New Road Bib Undershort, which, like the Mountain Bib Liner, sports three rear pockets. However, with a price tag of $150, the Bib Undershort costs more than $60 more and is not as breathable. Furthermore, the Giro Bib Undershort’s pockets tend to push down on the waistband of baggy shorts, as the pockets are attached at the bottom, unlike the Specialized Mountain Bib Liners.

Specialized has created itself a solid niche. For riders who want to forgo the hydration pack, perhaps for shorter rides, but still want to wear baggies and be able to carry a phone, some food, and maybe a tube, the Mountain Bib Liners are an excellent option.

Pros: Liberating, Ditch the pack, sub-$100 quality chamois, secure storage
Cons: Pockets take some getting used to to access
Price: $88