It's an age-old question. One that stumps (can grow in) the veteran of veterans in the dirt bike community.
What is the best type of dirt or soil for riding dirt bikes or Motocross?
MotoSport recently hired an independent lab to perform soil tests of Motocross tracks around the country measuring root variables, blue groove pliancy, moisture concentration, phosphorus levels, alkalinity and heavy metal presence.
OK, just kidding we didn't do anything of the sorts. That would be silly. It's expensive besides soil testing wouldn't tell us anything. Heck, we made up blue groove pliancy. In many respects the best dirt is what you ride best in (or is it on?). But for the majority of riders a favorite emerges and we'll try and soil it all out for you.
Good Dirt vs. Bad Dirt
If you want to know the best dirt for riding dirt bikes go ask your mom. Or whoever is the gardener in your family. Because, ideally, the best dirt is the same stuff that helps gardens grow. Good dirt holds water well and if you rip open a bag of potting soil and run your hands through it, just imagine riding your dirt bike on it. Oh yeah.
This is the best kind of dirt.
The worst kind of dirt? Well, if you're from Southern California you're riding on it. Clay sucks. It sucks the life out of plants and sucks the life out of your ability to stay upright on a dirt bike. Back to the blue groove. Blue groove is hard pack clay that slowly eats away at your tires and eventually the color of the ground turns blue. That's the rubber from your tires! It's slippery, especially when wet, and traction is nearly non-existent.
Soil Types
What makes Motocross so intriguing is the different soil types around the country. That's why when Supercross heads east there's so much talk of how different the soil is from the West Coast and why Rider X, Y or Z finally has a chance to win. Or something like that. Soils clearly have little effect on repeating Champions.
Bottom line is don't expect to ride on perfectly sculpted tracks made of loam each and every time. Expect the unexpected and you'll not only grab the holeshot but step on the podium. So what are the soil types you can expect to ride on?
Clay Soil
Think nearly dried out Play-Doh. It's hard, already compact which only gets more compact as you ride on it. Which leads to the aforementioned blue groove. Thankfully, tire manufacturers figured out a knobby way to get traction in this stuff.
In certain areas of the country (cough - southerncalifornia - cough) there's no way around riding on clay soil. Hopefully the track masters have imported any of the below to balance the composition.
Silty Soil
Have you ever stepped foot on the banks of a river or lake and a soft, almost massaging feel of mud hugged your feet? This is silt. When it's dry it blows with the wind. Silt texture resembles clay when wet, but finer than sand when dry. It's a pretty good soil to ride on if it's prepped well. The problem is finding the sweet spot between wet and dry. Too much water truck and you're riding on mud; not enough moisture and you've got a dust bowl.
Many Motocross tracks use silt soil but not exclusively. It just wouldn't work. The silt gets trucked in to help balance out a heavily clayed track, for example.
Loamy Soil
Mmmm, loamy. Got to loooove the loam. This is everyone's favorite soil for riding. Well, almost everyone. Loam is a mixture of clay, sand and silt for the perfect riding conditions. It offers grip, excellent drainage and if you fall it's like landing on pillows. The Midwest is wrought with loam because that's what farms use to grow crops.
Remember what we said? Good for gardening; good for riding.
Sandy Soil
Those dastardly sand tracks or should they be called sand traps? Hey, some riders love the sand others never figure it out. Sand is used in the joker lane for the Monster Energy Cup, if that gives you any idea. It's sloooooow and requires a completely different set of tires. You could say sand offers too much traction in that it grabs and holds you down. But the reality is sandy conditions prove slippery and you've got to keep the throttle rolled if you want to stay upright.
The Sandbox at Southwick
Peaty Soil
Best for single malt scotch. Oh, wait. Wrong website. There's no such thing as an exclusively peat track. Imagine riding on peat moss. It's great for plants (thanks to its nutrient content) when combined with other materials. Thus peat soil combined with other thicker soil, like clay, is great for dirt bikes.
Saline Soil
Saline soil is simply soil with high salt content. It's brutal on crops and you actually may ride on it if fresh soil trucked in to enhance a degrading Motocross track contains high sodium. You can identify saline soil by the white coating on top of usually dry soil. Once mixed with other soil the sodium content lowers and the white stuff (salt) goes away.
Chalky Soil
Chalky soil is your run of the mill backyard dirt. It's widely used in gardening but typically combined with any of the above to improve nutrients, density and drainage. It likely makes up a large portion of Motocross tracks and for those with property and determination it pretty much makes up the bulk of a backyard track. It dries quickly though so watering is a must to keep the dust down and traction consistent.
Underwear Soil
This is the absolute worst kind of soil. Underwear soil occurs because a high profile jump scared the crap out of the rider or a rider ignored the stomach rumblings after eating something questionable and went riding anyway. The only way off this ride is during a mud race. Fake a crash and no one is the wiser.
Only one reason to dump yourself and your dirt bike in this
If you've been riding dirt bikes for a while you've probably experienced all of the above soil types with hopefully one exception. Certainly ideal soil conditions exist but, even in the worst dirt, with proper set-up and the right tires the blue grooviest of tracks can be conquered.
