# 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

13 replies
1. Louis says:

Thanks Lee,
This will save us TONS of re-do time!!!! I’ll send you the photos as the track takes form. Starting 4/28. Best Regards, Louis

2. Justin Brown says:

Wow, this is perfect for what I want/need to do for my track. I have a 12 foot berm that just doesn’t carry enough speed, but I like your “S” turns at the bottom of that track. It’s weird, cause mine looks just like that minus the “S”. I’ll be building..tearing down first then building is what I meant to say. Thanks for that. I’ll take pictures when it’s “done.”

3. Walt says:

16″ seems kind of low to get a good pump. (I bought the book too, by the way – 2 1/2 years ago) Does it mean 16″ to the level ground and then, of course another 16″ to the bottom of the trough? Or does it actually mean 16″ from the top to the bottom of the trough? I never got this part. I have a lot of work to do on mine when the snow melts off.

4. leelikesbikes says:

16 inches is actually pretty tall.

In the ebook, I mean from trough to peak.

Most people make their rollers too tall and peaky.

5. dylan says:

I have built in almost 6 180’s, in to my pump track all of which are ride able from any direction. They range from 6′ to 10′ radius. Some may be even small because I threw out the tape after the first few. The three that I put in a row are progressively smaller or larger depending on which route you tack. Here is a video link

6. leelikesbikes says:

7. Jesse says:

Hey Louis.

I just got my eye caught by the words “Dryer Road Park” up top there. The current one needs serious TLC. I was actually at the park today. I havn’t ever completed a full lap on the track. I think that design will work so much better. Much more pump in that one. Is there an official build day for the pump track? If not please contact me as I’d love to give a hand. I’m only 10 minutes away.

jesscars@frontiernet.net

8. Sam says:

Thanks for all the good info Lee!

I have another 180 degree question for you-

I did buy your book and am midway through building, but have never ridden a track at all, so I don’t know any more about what I’m doing than I learned from PTN.

The diagrams are great, I have a space in between the two larger figure eights you drew.

I have a 43×20 space (interior dimension, the berms are mostly outside of that.

I’m mostly done with the outside loop –

Can I have two 180 degree 10′ diameter turns that close together?
(22 feet apart.)

one side has four 8″ berms aat 7′, and the other has three 12″ at 11′

Or would it be better to break up one side into two 7′(or smaller???) radius turns with two rollers in the middle?

Thanks for getting me stoked.

Sam

9. leelikesbikes says:

It’s hard to visualize. Finish building the current layout. Ride as much as you can. By the time you decide to expand, you’ll have a feel for what works.

***Do not bite off too much. Start simple. Build it very well. Ride it. Then go from there.***

10. Cheeky Monkey says:

***Do not bite off too much. Start simple. Build it very well. Ride it. Then go from there.***

Amen to that. We’ve built and re-built lots of stuff several times to get it to work. We’ve also just dug channels for drainage that make the whole track unrideable – bummer 🙁 Need pipe and rock to complete them and then just a little of the rarest commodity when you’ve two kids and a “regular” job – time!

PT’s are a rare thing in the UK so it’s not like folks have a lot of experience building them. We’re learning as we build which leads to a few more mistakes than average. Mistakes mean more digging and packing. They also make it a nadgerier track though 🙂

11. leichel says:

Thanks for all the input from everyone! The details for the pump track workday (This Saturday starting at 9am) are all on the mygroc.com website. I am planning on making those bottom berms just as you said Lee, and the top berm will be 12 feet with the rollers on the inside. I also plan to make a swooping table top type roller similar to the ones in the latest Sea Otter pump track video (http://youtube.com/watch?v=ATSK-I9N7ss) for some of the x over rollers. I am marking it out tomorrow. In terms of the outside roller height being 16 inches, the track is designed to give beginners and intermediate riders a smooth track to get started on. Then they can attack the middle larger features as they get better. The whole track will be built on flat (no troughs) to avoid drainage problems since we live in a rainy climate (Rochester, NY). Thanks again!