Bike
MTB
How to build turns into a mountain bike trail
Part 3 of the trail building series explains how to design and build turns and berms into a mountain bike trail.
Once you’ve got the right tools and the basics of mountain bike trail building dialled, as explained in Part 2, you’ll want to start crafting the next great masterpiece of flow.
Where to start? At the beginning, of course, but if we are going to look at one feature that is never going out of fashion, it’s the corner. You’ll need it to navigate around trees and to follow the line of the hill, but you’ll also use it for fun. There’s nothing like throwing a bike into a well-built turn.
Trail builder extraordinaire, Nikki Whiles of Trailcraft Track Construction, is back with some advice on shaping the best turns in the business. Corners that will stand the test of time, will add fun and flow to a trail and won’t sink beneath a sea of muddy water every time it rains.
What tools to use and for what
Some tools you might find useful for trail building
© Nastya Kvokka / Unsplash
If you’ve taken note of the tools Nikki recommended in Part 1 – or even if you haven’t – it’s time to get to work. As with any feature, the build comes in stages. First, you’ll need to remove the top layer of organic matter in order to get down to the good dirt that will hold together and form a long-lasting turn. Build this dirt into a turn of whatever shape and size you fancy. Soon enough you’ll know if it works or not. Riding the turn will help form it into a smooth arc.
"Get the organic off the top using a rake or hoe. Use a mattock or hoe to bust the ground up and move the dirt using a shovel or hoe into your turn shape. If it’s pure loam heaven you could always snap some branches, kick it in with your feet and let the riding do the building!" – Nikki
Where to build turns
Where you put a turn in might depend entirely on the area you are building. Trees, rocks, drops and other natural and man-made features could completely dictate the course your trail takes. If you have the luxury of choosing the track’s route, it’ll pay dividends to think ahead at where and why you put a turn in.
A perfect turn in La Bresse
© Bartek Woliński
"Try and look for good ground (not wet, boggy, too steep, too flat). It will make life a lot easier when building. Try and control speed where you can. The faster the rider is going, the bigger the turn has to be in order to hold the speed, which means more work. Nice, constant shapes, no drastic changes in direction or sharp angles are key. Always think about water and where it’s going to go. The easiest way is to make it run out of the exit. Tree roots can be a pain to dig around. Try to dig where you think there might be a gap in the roots. It will save your back." – Nikki
What arc?
If you are looking to build flow into a trail, then you’re going to have to do some experimenting in order to find a good radius for your turns. If you’re looking to make it tight and technical, well, you might find there are limits too.
A tight berm!
© Christoph Oberschneider
"When I first started I always used to build turns too tight. What looked right ended up being way too tight when riding. I try now to always keep them above a certain radius. You have to judge a turns radius by the speed of the rider coming in. If they are coming in hot, then you’re not going to want it to be too tight. If you build tighter turns, then you kind of end up with a longer trail. It slows the rider down and you get to fit more in. It’s personal preference. I definitely think there is a certain radius to a corner that you should go beyond as it will be too tight to ride." – Nikki
Banking it up
Speeding to his first ever World Cup win
© Bartek Woliński
Turns don’t need to be berms, even if a lot of them are.
"Sometimes if you don’t bank a turn up then everyone ends up running wide and going off the track. This can be super dangerous and make it pretty hard to ride. Equally, a flattish turn can be fun and challenging. It’s down to the eye of the builder and using sense to figure out if it needs banking up. Always to try ride it a bit while building, that will give you a much better sense of what it needs." – Nikki
Drainage
A great turn can become a turn to avoid when the weather changes. Plan the drainage and it’ll stay good even through the worst of weather.
Nothing but dirt!
© Lukas Wagneter/Red Bull Content Pool
"Turns full of water are no good. You can put a pipe on the inside of the turn so the water runs through and out of the back, but it’s better to build the turn with a downhill exit so the water just runs out of the end. I always try to do that as pipes usually block up and need some sort of maintenance in the future. Water management is a crucial part of trail building. No one likes wet feet." – Nikki
Sustainability
Flat out straights or steep drops into ruts are great fun, but if you are looking to create a trail that lasts, you’ll need to shape the trail so that last-minute brake checks are kept to a minimum.
The small uphill before the berm controls the speed from the steep chute
© Dan Griffiths
"The key to sustainability is controlling people’s speed and making turns with enough support where needed to eliminate sliding and skidding – that will destroy the berm eventually. A little bit of uphill before the turn is a nice way of controlling speed. Avoid very steep chutes into corners. This will create a lot of heavy braking and cause bad bumps and ruts." – Nikki
Many thanks to Nikki Whiles and TrailCraft for their help in preparing this article.
