Reading the Dirt

By Jeremiah Stone

One of the best parts about mountain biking is traveling to new places and exploring new trails. We’re all familiar with our local trails, but what about all the other surfaces you might encounter? Here are some of the most famous (and infamous) trail surfaces and how they affect your riding.

Rule #1. Moisture is good, mud is bad

It takes a little moisture to settle the dust and prime the soil for perfect days, but mud is a red flag. It not only destroys your bike, but it wreaks havoc on the trails we love. A good rule to follow: if you’re leaving ruts or tracks then today isn’t the day to ride. Even if you’re antsy and jonesing for a pedal, it will cost the local trail crew multiple days of fixing ruts and drainage issues. Oh… and the bad voodoo we as trail builders wish upon those who ride muddy trails? You don’t want that in your life. Promise.

Let’s break down surface conditions and how to deal with them starting with the shiftiest.

1. Sand

Riding in sand can be a real beach. It will grab your tires, take a jarring bite out of your speed, and always seems to appear right after a nice hard-packed section or on a corner. Prepare by shifting your weight back and steering with your hips while maintaining your momentum. Looking for a detailed play by play on how to tackle sand? We have a skills article for that!

mountain biking in sand
(Photo courtesy of First Tracks Productions)

2. Kitty Litter

A loose, gritty surface that’s not quite sand, not quite gravel, and usually the ground is rock hard underneath it. Definitely sketchy! You’ll want to air down the tires a touch and pay attention to your body position in corners, otherwise that front end can wash right out from underneath you. Another word of caution: it’s harder to stop on the surface, so initiate your braking early and keep it smooth!

Also known as: Dippin’ Dots

3. Moon Dust

Found in arid regions as well as non-arid regions after long periods without rain, it’s a deep fluffy baby powder-like dirt. It wants to swallow your front wheel, steal your momentum, and thoroughly coat the inside of your mouth and nose! Use your sand riding techniques, keep your weight centered/ back, and try your best to “float” over it. Luckily, the learning curve for this one is usually forgiving – taking a fall isn’t as brutal as other surfaces!

Also known as: Baby Powder, Blown Out

Racer in Bend’s Single Speed World Championships 2018

4. Loam

Truly black gold. Found in the rich forests of the Northwest, it’s a deep, dark soil made of silt, sand and clay with a hefty dose of decomposing plant material. The knobs of your tires reach their full potential here, digging in to allow for bar-dragging turns and powerful, controlled braking. But make sure you stay loose and ready, because loam is usually going to involve some roots as well!

Also known as: Brown Pow

5. Chunder

These are the rockier trails where the rocks themselves are actually loose. Some are rounded, others more square edged resembling bricks, plates, or even big books. These are more difficult to deal with, because the rocks are moving and therefore can’t be trusted. Best advice: stay loose in the hips, keep your weight centered, and manage your speed without using a ton of front brake.  Do your best to choose your lines wisely and prepare for your bike to buck to and fro beneath you.

Pro Tip: Put on headphones for these trails so you don’t have to hear the terrible sounds it makes when rocks batter your beautiful bike.

Also known as: Baby Heads, Chunder Muffins, China Cabinet, Brickyard, Bookcase

4. Clay

This is as close to pavement as you’ll get on a soil trail. It packs down hard, is prime for building flow trails, and rolls fast and smooth. You might encounter loose corners with tiny clay ballbearings, so mind your speed until you’re familiar! In high traffic zones, the tire tread will color it a bluish gray.

Also known as: Blue Groove

6. Rocks

The non-moving, stuck in the ground type. They’re not all equal and they can’t all be trusted. Mountain biking around the country can give you a hands-on geology lesson with varying terrain, colors, and textures. Be prepared to encounter rowdy, steep slabs and off-camber lines, but when it comes to traction, each type behaves a little differently.

Weight your outside (downhill) foot when you’re on off-camber angles to help the tires hold traction and lose a few PSI in your tires for maximum grip. When it comes to steeps, look before you leap. Examine your entrance point and mark it with a couple rocks to help guide you. From there have a plan of where to go with the momentum and be mindful of the runout because you’ll be accelerating!

Sandstone

Loads of traction in most conditions, but rider beware: add a layer of dust to the equation and things can get slippery. Want to ride some world-class sandstone? Check out Moab and Sedona!

Also known as: Slickrock

Granite

The grippiest of rock surfaces offers traction even when wet – just beware when there’s mud or moss involved! It often has great shapes that make for some very entertaining bike techniques.

Also known as: Slabs

Limestone

When dry, it’s not too bad, but introduce some moisture and things change. Limestone will get slippery and difficult when wet, so pay close attention to creek crossings and armored bits if it’s been damp or even mega humid! Stay loose, manage speed without dramatic front brake action, and make good choices. If I see a limestone feature with moss or moisture, I either skip it or walk it to avoid that surprise face plant potential.

Also known as: umm… Slippy Slabbies?

7. The holy grail of trail conditions: HERO DIRT!

Sometimes the stars align and the perfect combination of moisture, soil composition, and temperatures creates this magical substance. There’s no dust, no slop, just pure traction. Come to the trail ready for a taste of what it feels like to rail a corner better than ever before and nail the line you’ve been trying to hit. You’ll ride away knowing that you’ve experienced something magical and feeling like a true bike hero!

Also known as: Velcro Rojo, Primo, Sticky Icky, The Tacktastic Voyage

One Thought on “Reading the Dirt

  1. Hi,
    This is such a handy informative article. Thanks for your valuable suggestions. It is really important to know as dirt-bike riders. Keep sharing your suggestions with us.

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