# Pump tracks: Minimum radius for a 260-degree turn?

Hi, pumptrack question…

In your last book you mention, that 6X9m land is needed for a minimal pump track. I have long but narrow land in my backyard, so in one part there is space only for one line that will be ridden in both directions. But the problem is almost 270 degree turn that slould be made in one end… What you think is minimal radius for a 260° turn?

Janez

Janez,

When we built our first pump track (at the old The Fix Bike Shop in Boulder, CO), the radius of the 180-degree turn was less than 2 meters. We didn’t know any better, and we could barely ride it at first! But we all learned to ride it.

A certain world champion named Brian Lopes rode it just fine:

1) Make the radius as large as possible. If you build a vertical retaining wall on the back of your berm, that leaves more space for a wider turn.

2) Let’s say 2 meters is the tightest you want to go. It’s tightest I’ve seen that works. The wider the better, up to about 4 meters. The sweet spot is about 3 meters (10-12 feet).

3) Make the berm as steep as possible. It should transition smoothly from level in the middle of the turn to steep at the top of the berm. Strive for a 70-degree angle on the high riding line. This will support a 3G turn, and that’s plenty. In the Lopes shot above, notice how he’s extending his left foot? That’s because the berm isn’t steep enough for the speed he’s carrying, and he needs more edging bite. If you build your berm correctly, you’ll be able to pump it with level feet.

4) Plan thrice. Measure twice. Build once. Ride infinitely.

Lee

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