The Big-Wheeled Benchmark

Manufacturer

Surly

Model

Krampus

Frame material

Steel

Wheel size

29+

Gear ratio

30x20

Fork

RockShox Pike Ultimate, 130 mm

Wheels

Stan's rims with Chris King hubs

Tires

Surly Dirt Wizard 29x3

Owner

Blake Cannon

Build purpose

Loose, rocky Colorado trail riding

My first single-speed mountain bike was an inexpensive On-One Inbred assembled from whatever parts I could find.

It taught me why riding one gear was fun.

The Krampus was what happened after I already knew.

This was not a bike built simply to slow me down or make familiar trails harder. It was a more deliberate version of the idea: big wheels, big tires, a steel frame, capable suspension, and one gear chosen for the terrain around Golden.

The Inbred started the obsession.

The Krampus became the benchmark.

Big Wheels, Big Tires, One Gear

The Surly Krampus was one of the bikes that helped define the 29+ category: 29-inch wheels wrapped in tires around three inches wide.

Mine runs Surly Dirt Wizard 29x3 tires, although they measure closer to a modern 29x2.8 once mounted. They are still large enough to give the bike its defining character.

The tires smooth out loose rock, add traction on technical climbs, and preserve momentum through sections where a narrower tire might get knocked off line.

That momentum matters on a single speed.

With no easier gear waiting at the handlebar, every bit of speed you carry into a climb becomes useful. The Krampus rewards looking farther ahead, choosing a clean line, and resisting the urge to coast too early.

Once it is moving, it wants to keep moving.

Built With Intention

Unlike the Inbred, the Krampus was not assembled simply from the cheapest pile of parts I could gather.

It still reflects the practical, mix-and-match nature of single-speed mountain bikes, but the overall build has become much more intentional.

The steel frame is paired with a 130 mm RockShox Pike Ultimate. That gives the bike enough suspension for rocky Colorado trails without taking away the directness that makes the Krampus engaging.

The wheels use Stan's rims and Chris King hubs. The Dirt Wizards provide the grip and volume that make the bike feel different from a conventional 29er.

In single-speed form, it runs a 30-tooth chainring and a 20-tooth rear cog.

Thirty by twenty is not a heroic gear.

It is a gear chosen for actually riding the bike.

There are ratios that look more impressive in a parking lot, but Colorado climbs have a way of correcting that kind of optimism.

Momentum Over Agility

The Krampus is not especially small, light, or delicate.

It does not dart through the trail in the same way as a shorter-wheelbase bike. It feels taller, longer, and more committed to the direction it is already traveling.

That is part of the appeal.

The big wheels and tires roll through rough terrain with confidence. Loose rocks that might deflect another bike are often absorbed or simply rolled over. The bike feels stable when the trail gets fast and composed when the surface gets ugly.

The tradeoff is that it takes effort to change direction quickly, and even more effort to accelerate once momentum has disappeared.

On a geared bike, losing speed before a climb means shifting down.

On the Krampus, it means standing up and trying harder.

Sometimes it means pushing.

Single speeding is actually three speeds: pedal, coast, and push.

The Krampus uses all three.

One Drivetrain, Two Bikes

The Krampus now shares a drivetrain with my Surly Karate Monkey.

I can decide which bike will be geared and which one will be single speed, then move the drivetrain between them.

The chainstay-length difference even allows both bikes to use the same chain in their respective single-speed configurations:

• Krampus: 30x20
• Karate Monkey: 32x20

That probably says more about how much time I spend thinking about unnecessary bicycle details than anything else.

But it also fits the spirit of both bikes.

Neither build is completely fixed. Parts move. Configurations change. One bike becomes geared while the other returns to one cog.

The important thing is that there is always a single speed ready to ride.

The Long-Legged One

The Karate Monkey is the snappier of the two bikes.

Its smaller 27.5+ wheels make it easier to accelerate, easier to move around, and more playful when the trail tightens up.

The Krampus is the long-legged one.

It carries speed better. It feels calmer in rough terrain. It rolls over obstacles with less drama and encourages a style of riding built around momentum rather than quick reactions.

Neither is universally better.

They simply express the same idea differently.

The Karate Monkey feels eager.

The Krampus feels inevitable.

More Than a Conversion

A lot of single speeds begin as compromises.

A derailleur breaks. An old frame needs a purpose. A collection of spare parts becomes a bicycle because nobody can think of a good reason not to assemble it.

The Krampus is different.

It is not a temporary conversion waiting to become a "real" bike again. It is not missing anything. It is not unfinished.

It is a capable trail bike intentionally configured around one gear.

The large tires provide traction and forgiveness. The fork handles the rougher terrain. The steel frame gives the bike the durability and character I want. The 30x20 ratio makes the local climbs difficult without making every ride ridiculous.

Most of the time, anyway.

The Benchmark

The On-One Inbred showed me how much fun a simple bike could be.

The Krampus took that lesson and removed the accidental parts.

It kept the simplicity but added capability. It kept the effort but added traction. It kept the questionable decision to ride one gear and wrapped it in a bike that could handle nearly anything I reasonably wanted to point it toward.

Every other single-speed mountain bike I build now gets compared to it.

Is it quicker?

Is it more playful?

Does it climb better?

Does it carry speed as well?

Would I rather take it when the trail is loose, rocky, and long?

The answers vary.

The point of comparison does not.

The Inbred was the bike that started it.

The Krampus is the bike that showed me exactly what I wanted a single-speed mountain bike to be.

• mountain-bike
• single-speed
• steel
• hardtail
• surly
• plus-bike