Gravel and Adventure Bikes
Not too long ago, if you marched into a bike shop and requested a “road bike”, you’d be presented with a bike with a svelte frame, drop handlebars and razor-thin tires. A bike like this could carry you like the wind over a smooth paved surface: tight, aerodynamic and nimble, not and ounce of spare fat to be found anywhere.
Bikes like this still exit, as no doubt do perfectly smooth asphalt surfaces — somewhere. But because most roads are imperfect —some of them delightfully so— and so are human beings, the single-minded road bikes have been displaced by much more laid back and versatile gravel bikes.
More durable than a road bike and much faster than a mountain bike, gravel bicycles are all about options. Gravel bikes can accommodate tire sizes ranging from something resembling a road bike (about 28mm), a typical hybrid (around 37mm), to monster dirt-chewing tires more commonly seen on off-road bikes (47mm+). This makes a gravel bike at home on almost any terrain. Its adaptability and ruggedness makes it a perfect commuting bike, an ideal light touring or adventure bike, a great winter training bike, or the perfect multi-tasker if you can only have one bike but enjoy a variety of biking styles.
A few other features distinguish gravel bikes from their all-road brethren. Without getting into specifics of frame geometry, suffice it to say that gravel bikes will generally give you a more relaxed and comfortable riding position. This has to do with the slight differences in frame angles for a ride that emphasizes comfort, stability and endurance over speed and agility. Gravel bikes are designed with longer wheelbases, so they’re stable over long distances, rough terrain or while fully loaded. A sloping top tube gives the rider a little more clearance, which is useful in maneuvering the bike over unpredictable terrain, and getting on and off while carrying gear. A taller head tube gives the rider a more upright position, better for viewing the scenery and more comfortable over long distances.
All gravel bikes feature disc brakes. Cable-actuated disc brakes are found on entry-level gravel bikes (<$1000), while more expensive models have hydraulic disc brakes. Disc brakes offer a number of advantages over rim brakes:
better stopping power in mixed conditions, such as rain, mud, dust and uneven terrain
more dependable stopping while carrying heavy loads
confident braking is independent of the wheels being perfectly true
braking action does not cause wear on the rims (affecting their lifespan)
Flexible Wheel/Tire Sizing
In addition to accommodating a variety of tire widths already mentioned, gravel bikes can run a couple of different wheel diameters. Not that you’d necessarily want to change wheels mid-stream, so to speak, but when you’re considering a new bike, you can choose a wheel size that is most appropriate to your preferred style of riding. Since gravel bikes don’t have rim brakes, and the frames are made with very generous tire clearances in mind, you can choose:
a more traditional 700c road size wheel, excellent for commuting, touring and hard-pack riding, or
a smaller 650b rim to run stubbier, higher-volume tires that will easily roll off-pavement and carry you on all-terrain bikepacking adventures (or over Chicago’s pothole-ridden post-winter streets)
Carrying Stuff, LOTS of Stuff
Gravel bikes are built for adventure, and figure prominently in the burgeoning category of “adventure bikes”'. They are designed to carry more stuff than traditional bikes, and carry it it more unconventional ways. While most bikes have provisions for attaching a rear rack, fenders and one or two water bottles, gravel bikes have additional eyelets on the fork and beneath the down-tube for mounting extra bottle cages, a variety or front racks and fork-mounted carriers for lightweight camping gear, and additional supplies that an adventuring cyclist might need.
Gravel bikes make fantastic urban vehicles, and adventure and bike-packing companions. However, for traditional long-distance road touring you should still consider a dedicated touring bike.