the Leelikesbikes "Welcome to Pump Track Nation" is written well, BUT . . the thing people don't realize is that it is primarily intended for backyards. if you have a lot of space, like a public park, do
not build a small 30 ft. X 70ft. oval or figure 8 pump track. that is not what mtb/bmx is all about !! that's a backyard pump track.
SO, lemme just give you some points that I think are essential to a good mtbmx spot.
1. if you are on flat ground, you MUST build a large starting hill, like at a bmx track. there is nothing as lame as having to crank from a standstill.
2. build at least 3 different jump lines with different heights and gaps. the standard bmx skatepark box jump in the old days was 4' tall with an 8' or 10' deck. that is an excellent size for a lot of riding levels. the difficulty has more to do with the mellowness or steepness of the transitions than with the size. for example, in the picture below, is 3 tabletops in a row. the height is probably somewhere between 3'6" on the first one and maybe 4'5" on the last one. the lip to landing gaps should match up pretty closely, unless you're going down hill. you don't want a short jump followed by a long one, or the reverse.
a 7-8 foot lip to landing gap is very easy. 9-10 is normal/intermediate. 11-12 is getting big (unless your transitions are mellow and it's easy to carry some distance. 13+ is intermediate/advanced level. for that to be fun, you MUST be on a decline slope, or have a BIG starting hill to drop in from.
3. space your rollers appropriately.
the rollers you see in the picture below on the left are spaced 13-14 ft. peak to peak. this is typical bmx race track style. you can gain speed, manual through them etc.
4. TABLES are good for beginner and intermediate scenes. if you want more people to show up (and potentially help in the future), build stuff they can ride. this table about 13 or 14 feet from lip to landing. note how deck of table transitions with a curve into the landing. this is good for beginners who are gonna tag their back wheel pretty hard.
5. public city/neighborhood spots should not be built by hand. if the city ok's a dirt jump spot, get someone to rent a bobcat and do all the fundamental work with heavy machinery. most beginner jump spots die before they get started because of the sheer amount of digging it takes to make an awesome spot.
6. resist the urge to make every jump look like a skatepark quarterpipe--one line of steep tranny jumps is cool, but build the others with mellow. you will get plenty of air and it will be a lot smoother.
7. avoid the mistake of small landings. landings are actually more important than launches. you want something that is big and long, starts steep at the top, but has mellow transition at the bottom. here is a typical beginner mistake. a 13' gap but the landing has barely enough surface to get the wheelbase of your bike on.
this is one of the big sets. around 18 feet lip to landing lip gap. but look how big the landing is. tons of transition to land on.
. the more transition you have to land on, no matter how big the jump, the more the jumps will have flow. flat ground is your enemy. rhythm comes from having back to back transitions. inclines, declines, curves.
hope that helps.
