Mountain Biking - Cracked Dirt Jumps

My recently constructed dirt jump is starting to crack on the transition and crumble on the sides. I was wondering if this is normal or if there is a way to fix this problem.

-thanks in advance

Hint dirt jumps require alot of maitenance, they need to be groomed after every time they are used, can't build them then let them be.

after the first time i used them i wetted them down, re-packed some of the dirt , and smoothed out the transition, then i let it dry over night and in the morning they were cracked. should i be doing something different?

Something is messed up then.

what would someone typicly do when maitenancing (sp?) a jump?

Harden them down, water, leave to dry. No idea what's wrong in your case.

oh, and how do you pack the sides, they're too steep to use your feet and smacking them with you shovel doesnt help alot either. any advice?

That's probably your problem right there. Just pack the sides down anyway you can.

any ideas on how to pack it , or should i just get "creative". And also, that still doesnt explain the transition, which is cracking even though it is well packed down.

-One more question, is it beat to pack dry or wet dirt?

Dirt packs better when its wet, but some dirt sticks to your shovel or foot when its wet also...

Try mixing a tiny amount of concrete into the dirt. Not enough to make it completely solid, but just enough to keep it together.

oh, and how do you pack the sides, they're too steep to use your feet and smacking them with you shovel doesnt help alot either. any advice?

Use like a 4 ft long 2x8 or even a 2x6. Grab each end and thrust it forward into the dirt. Do that enough and it will pack great. Also it might be cracking beacuse the soil might be too sandy. Try to find dark soil that has alot of organics in it (dead grass, dead leaves etc.) If you find good enough soil, you wont even need to wet it down, it will pack just fine and stay how you want it.

If you intend on having it around for a while you are going to need to get serious. In the short term understand that dirt is not ever the building material of choice. it does not compact and stay. It will weather very quickly unless you add something. Even for sidewalk, you should dig 4-6 inches below the forms and fill with a good compacting material, like different grades of stone. In order to get a real compaction you need different sized materials that will merge together when compacted. So, considering that I doubt you want a rock ramp, you will get much better results by putting your ramp down in layers. 2-4 inches, wet and compact, do it again. Takes more time but it should make your construction much stronger. Putting some gravel in the early layers if you have any will also help some. Oh, if you intend to keep it a while, do not put organics in it, they decompose and when they break down so does your ramp.

Oh, if you intend to keep it a while, do not put organics in it, they decompose and when they break down so does your ramp.

Ya, I didnt mean dead leaves that are still visible, what i meant was soil that has organics already broken down in it, very fertile soil.

Use clay

you could also buld the majority of the jump outta something that doest break apart so fast. We actually used logs as a base quite often, by the time they break down enough to mess up the jump i will be long gone from that spot..Other than that alot of maitnence.I know some of my friends who had mad jumps in thier back yard, they were bmx ers. They let the weeds grow on the sides that way the roots would hold. the trimmed the trails, but left the stuff on the sides..

like Psyko said, use something else as a base, my neighbor used old tires.

thanks for the advice