Pump tracks: 180-degree berm radii?

I rarely offer specific feedback on pump track designs, but Louis here bought the ebook, is building a public track and raised a good question. So here we go:

This 180 has an r of about eight feet. I can only rip it if I slow down before I dive in.

Hi Lee,
I used your pump track book to build a nice track in my backyard (THANKS!) and now I have been placed in charge of designing a larger track for our local bike park.

In my yard I used the space I had and it worked out well but the park track will be more formal. I have a level 90 ft X 75 ft area so there is plenty of space!

What is a good middle of the road radius for 3 berms in succession with rollers in between like switchbacks (specifically the berms at the bottom of this diagram)? I have enclosed a conceptual design that I think would work out well with an intermediate outside loop and some more advanced crossovers in the middle (see the .pdf).

I am not a pro with Adobe Illustrator so keep in mind that the rollers of the cross overs would really mesh more with outside loop rollers where they meet the berms so that the angle of entry to the berms would be smoother than in the schematic.

Also what radius would you recommend for the larger single berm at the top end?

Thanks, Louis

Hey Louis,

This is rad! I have a couple thoughts for you:

– If you have speed, 10 feet is a nice, railable 180-degree radius. If you’re trying to make speed, about six feet is better.

– If your top turn is too big (say much more than r12 feet), people won’t be able to pump it for speed. If you make the top turn as big as the diagram shows, try building some rollers into the bottom half of the berm. The new track at The Fix has this, and it works well. If you’re railing, you stay high above the rollers. If you want more speed, you stay low and pump the rollers.

– Very few people can make speed in 180s, especially when they are linked. On that bottom section, I suggest toning down the turns. Make the 180 switchback into more of a 90-degree slalom. See edited diagram below. This will be a lot easier for most people to ride.

Super cool. Send photos!

— Lee