Kicking off 2025 with a wonderful entry into our Vintage Bicycles category, Tasshi Dennis from the Vintage MTB Workshop pens a historical look at a 1986 Cunningham Expedition (#003) and asks a question that’s long been on everyone’s mind: What is a gravel bike, anyway? Read on for Tasshi’s hot take and some beautiful photos by John of a stunning Beautiful Bicycle…

Editor’s note: this is another one of those special moments in the documentation of historically significant bicycles. For others in this space, check out:

• Charlie Cunningham’s 2012 Personal 29er
• Wende Cragg’s 1978 Breezer Series I
• John’s 2012 Bruce Gordon Monster Cross

“I’ve been fortunate to own a lot of historic and very rare bicycles. By far, this is the bike I feel most lucky to own because I get to experience the joy of riding it anytime I want. Other very special bikes collect dust.” – Tasshi Dennis

What Is a Gravel Bike, Anyway?

At the most basic level, it’s any bike that gets ridden on gravel, or maybe just any bike capable of being ridden on gravel. That would even include garage queens that never touch the ground. None of this is really a qualifying statement since just about any bike is capable of being ridden on modest dirt or a gravel surface, from track bikes to fat bikes to every road and mountain bike incarnation in between. Even beach cruisers are up to the task.

Most gravel bikes today have drop bars and tires with a decent tread pattern, so people often refer to drop bar mountain bikes from the 1980s and 1990s as OG gravel bikes. As much as this makes some recoil at the thought, because those bikes were designed to be ridden in the roughest of conditions and had small but durable 26-inch wheels, it’s a public perception that is hard to fight.

If you are trying to optimize the design of a bike for riding fast on gravel surfaces over long distances, a few features do seem important: large wheels to roll over bumps, tires with some tread for loose surfaces, clearance for potential mud, multiple hand positions to reduce fatigue, decent brakes, and wide gearing for hilly terrain. Going back some decades, a couple of bike categories already seem to fit the bill to some degree: touring/rando bikes and cyclocross bikes.

The UCI limited competitive cyclocross tires to 33 mm, meaning there wasn’t industry motivation to offer larger, more capable off-road treads. Eventually, the advent of bigger tires for 29er mountain bikes made possible the “monster cross” bike, which might have begun pointing the way toward modern gravel bikes.

It’s worth noting that Bruce Gordon offered a 43 mm Rock ‘n Road knobby tire as early as 1988, but those primarily ended up on various touring models he offered that had sufficient clearance.

Touring and randonneur bikes have been around for a long time and are all about stability, particularly while carrying heavy loads. Long chain stays and slacker angles make for improved stability, but can still feel sluggish even when the extra weight is shed.

Cunningham Expedition: Gravel Mullet

A few other bikes broke the mold here and there, and one such example is this 1986 Cunningham Expedition, which weighs 21. 8 pounds as shown.

Something that often happens when you break the mold to build something new is people don’t know what to make of it. Charlie Cunningham was very fond of his Expedition model at the time, calling it out in his 1989 catalog as “ideal for efficient travel over varied terrain” and “tough enough to go anywhere a mountain bike can go with a little rider finesse. ”

He made a few of these bikes, and they sat on consignment at bike shops in the Bay Area, looking for owners willing to gamble on an odd-looking bike that some would call a “performance hybrid. ”Looking at the gravel-centric cycling world now, the irony can’t be overstated.

Charlie Cunningham’s bikes were typically designed around specific tires available at the time, and this Expedition is a classic example. He had always been a proponent of larger wheels to corner and roll better over rough terrain, having started his off-road riding in the late 1970s on road bikes.

He picked the largest rim available for the front wheel: 27 inches. Several Schwinn “racer” bike models used the biggest tire available in this rim size, just 1-3/8” (34.9 mm), but it got the combination of the biggest diameter and volume Charlie sought. Unfortunately, the tires were heavy and not of very high quality. For the rear, Charlie went with a European 700c rim, which is only 8 mm smaller in diameter than a 27”.

But he kept the chainstays short like a road racing bike at 415 mm for snappy handling. With the big 1-1/2 seat tube, getting enough clearance for a 32 mm tire required dimpling the back side into a D-shaped cross-section. A couple of the Expedition bikes have 700c wheels front and rear, and those owners can count themselves as lucky today with far more tire options to choose from. Those bikes comfortably fit a 40 mm tire in the front and a 35 mm tire in the rear.

For the mullet bike presented here, the best high-quality tire option available in both 700c and 27-inch is the Panaracer Pasela. The thought of making a special set of cantilever brake arms to drop the brake pads down 4 mm for a 700c rim has a lot of appeal, even if it reduces the quirkiness factor. As popular as mullet wheel setups are on modern Enduro mountain bikes, maybe mullet gravel bikes are the next big thing. Mr. Cunningham was already there in 1986.

Given that the wheel diameter difference is so subtle, what often strikes people most about the appearance of the bike is the heavily sloping top tube. Fellow mountain bike pioneer Joe Breeze has said, “Charlie’s disregard for prevailing frame dogma makes me look like a sissy.”

One should remember that in 1986, every skinny-tired road bike in the European peloton had a horizontal top tube. The same could be said for the vast majority of mountain bikes produced at the time, and for good reason. Skinny 26.8 mm and 27.2 mm seatposts were prone to bending or breaking when they are made too long.

A few intrepid companies like Interloc Racing Design (IRD) and Syncros eventually offered posts of 400 mm or longer, which is what this bike requires. But that’s really starting to ask for trouble for both the frame and post.

Parts Configuration

Charlie’s solution was to use a massive 1-3/8 inch (35 mm) seatpost diameter, which meant he could routinely design frames around a 450 mm seatpost length. As massive as these big posts look, they are paper thin, and they use a simple fixed-angle design that is machined to the right angle to level out the saddle.

If you want to run a different saddle design, have a milling machine nearby. The saddle, in this case, is a bare plastic Cinelli Unicanitor, which is essentially a padded leather saddle with all of that removed. As an added bonus of the large seatpost, a frame pump stores inside it easily.

In the controls department, Charlie was known to manually flare rather soft Cinelli Giro D’Italia handlebars to provide more wrist clearance in the drops. It’s nothing like the flare of a classic Wilderness Trail Bikes RM-2, nor any modern gravel handlebar. Charlie wanted to be able squeeze his bikes between narrowly spaced trees in the woods of Marin. For reasons unknown, Charlie preferred rudimentary Campagnolo friction bar end shifters, whereas this bike has ubiquitous Suntour Mighty-Click Barcons. For more direct cable pull, the brake levers of choice are a non-aero design.

The brake configuration is unique to the Expedition bikes: a Mafac cantilever up front and a WTB Mini-Rollercam out back. The cantilever is the long-arm tandem model, selected for this bike because of extended steep descents encountered in the Rocky Mountains.

Putting a cantilever in the back like a cross bike wouldn’t have worked well because of heel clearance problems with the low seat stays. The Mini-Rollercam tucks under the bike nicely while providing good stopping power but can get fouled up in muddy conditions. As an aesthetic bonus, the seat stays have the clean appearance we have come to expect from modern disc brake bikes.

Unless you remove the rear wheel and get out a tape measure, you won’t notice that the rear hub spacing is a wide 135 mm. On a skinny tire bike. In 1986! Although this became the standard on mountain bikes in the late 1980s and through the 1990s, it never caught on with road bikes until we ended up with today’s thru axle hubs. For Charlie, it was the right engineering choice for a stronger wheel that, again, allowed these bikes to “go anywhere a mountain bike can go with a little rider finesse. ”Charlie provided modified Hi-E Engineering hubs configured with custom axles.

The gearing resembles a compact road bike, with a 36/46 double up front and a 12 to 26 road freewheel in back. If you jump into a paceline on this bike, you’re going to spin out. On hilly gravel courses, it might not be low enough for the steeper stuff, but that can be solved by simply finding a wider freewheel. The seven-speed Dura Ace Uniglide freewheel on this bike is arguably the nicest ever made.

Other little quirks include the rear-facing dropouts, which make wheel changes slower, but the rear derailleur hanger is so much stronger. The wheels are held on with Charlie’s Slo-Release skewers, which need a separate 2-inch rod to be used as a “key” to undo them. Again, it’s slower in operation, but the result is very clean-looking with minimal weight.

Also, for a cleaner appearance, the stem is held on with an expanding collet system that attaches to a conical extension above the fork steerer. Each time you get out of the saddle, your knees thank you for not making contact with protruding pinch bolts. The front derailleur has a custom band to go around the large seat tube.

So how would one describe the ride of the bike in one word? Zippy. As much as the frame numbers support this impression, the visual appearance of the bike, with unconventional tube angles, screams this too. The rider feels obliged not to take all day to complete a route. That the route can be strewn with gravel, washboard, singletrack, climbs, and many other challenges is what puts this bike over the top and into a category of its own.

Thank you, Charlie Cunningham, for your vision.

The Build:

Year: 1986
Serial Number: #003
Frame: Cunningham Expedition
Fork: Cunningham Type IV
Stem: Cunningham
Headset: Edco Competition
Bottom Bracket: Cartridge Bearing Grease Guard
Handlebar: Cinelli Giro D’Italia 64-40 Modified
Shifters: Suntour Barcon Mighty Click
Front Derailleur: Suntour Cyclone M-II
Rear Derailleur: Shimano 600 SIS
Brake Levers: Shimano 600
Front Brake: Mafac Tandem Cantilever
Rear Brake: Wilderness Trail Bikes Mini-Cam
Crankset: Specialized Touring
Chainrings: Specialized 36-46
Pedals: Suntour Superbe w/ Cinelli Alloy Clips (shown with SPD)
Hubs: WTB Modifed Hi-E Engineering
Rims: Araya 20A 27″ front and 700c rear
Tires: Panaracer Pasela 1-1/4” and 32 mm
Wheel QR: Cunningham Slo-Release
Seatpost: Cunningham Fixed Angle
Saddle: Cinelli Unicanitor
Bar Tape: Velox
Chain: Sedis
Cogs: Shimano Dura Ace Freewheel
Weight: 21. 8 pounds