The Science and Math Behind Mountain Bike Trails


If you’ve ridden a new mountain bike recently you know there’s a ton of technology built into almost every bike part imaginable. From carbon fiber handlebars sloped to precise angles to hydraulic disc brakes and nano-engineered tires, it’s clear that serious research goes into building the best mountain bike equipment. But it turns out that bikes aren’t the only thing getting a boost from science and engineering these days: trails and trail building are becoming high tech too.

Environmental and Social Research

At the IMBA World Summit I got a chance to hear about the latest and greatest in trail planning and building and I was blown away by the academic rigor behind seemingly simple ribbons of dirt. For example, did you know there’s a field of study known as “recreation ecology” full of PhDs who study the impact of recreation on the environment? These guys and gals set up experiments to measure the impact various trail users (hikers, bikers, equestrians) have on the environment (erosion, wildlife, plants, etc.) and run regressions to find correlations. While this field of study is fairly new, most of the early reports show no statistical difference in environmental impacts due to hikers and bikers (good news).

Recreation ecologists also set up sociological experiments to see how trail users interact with the environment. In one example, researchers wanted to know how signage affected illegal trail usage in a particular park. They put up signs and observed who ventured off trail and even surveyed folks in the parking lot afterward to learn more about their trail choices. This study in particular found that signs aren’t very effective at keeping folks on the official trails so it’s back to the drawing board to find a better way to manage illegal trails.

Trail Use Data Counts

I have to admit I’m a big data geek and when I heard about trail traffic counts I got pretty excited. Companies like Trafx make trail counter systems that can detect when mountain bikers enter or exit a trail and the data can be analyzed to understand trail usage patterns. In fact, you may regularly ride at a trail with a counter system in place without even knowing it (most systems are unobtrusive). At Blankets Creek in Woodstock, GA, trail managers have placed counters at the trailhead and at the entrances to three loops to see how things like weather and trail design affect usage. We’re hoping to take a closer look at the Blankets Creek data for an upcoming article.

Trail Building Techniques and Best Practices

Finally, there’s a lot of technology and research that goes into creating sustainable trails through chronically wet areas. Wet conditions are the number one enemy to trail maintainers so groups like IMBA have developed methods for improving conditions where trails go through low lying areas. It turns out the best method for improving a wet trail is to add a solid foundation which involves digging a trench along the trail, filling it with rock, then covering it with native soil. Sound time consuming and difficult? It is. And yet, many of us zoom along the trail and have no idea what went into making the trail so fast and flowy. To give you an idea of the difficulty involved, typical construction costs for bike trails are in the neighborhood of $3-5 per foot (that’s about $15 – 25K per mile) but a foundation jacks that up to $10-15 per foot (as much as $80K per mile)!

These days even dirt is becoming high tech and the trend only seems to be accelerating. The upshot is more sustainable, fun trails are being built all over the world for mountain bikers to enjoy on their high tech rigs!

This is the first of a series of articles from the 2010 IMBA World Summit held earlier this month in Augusta, GA.