[stino]

Hi folks!

hope this is no repost but I'm no native English speaker so can't figure out the right search terms appeareantely.
Anyway, here's the deal: we've been digging around in the woods in my backyard; we have some small jumps and 2 larger ones, together with some curves; water flows where it should flow, ie out of the way of the riding areas. All basic starter stuff, at least for now.
Very much fun to ride it, at least when the dirt gets dry.
Last week there where up to 4 days without rain, temperature of about 10degrees celcius during the day, yet we're stuck with a nasty problem: the dirt right in front of the kickers doesn't seem to want to get dry; it looks dry, but in fact it's some sticky kind of mud: riding it pushes aside the dirt leaving you with a 'trace' of 5cm deep. If we don't repair that before the next rain, water stays in; in fact, not repairing it just feels weird because riding anywhere near it automatically makes your wheels slip into it.
Problem occurs at all jumps except one, yet we didn't do anything different to build that one. The dirt in the area ranges from dark brown (upper 20cm layer) to more yellowish (everything beneath); we think it has a lot of clay in it because it's pretty sticky in general.

Now, we're not really sure what to do about it, if anything can be done, so my thought was to ask around on the vast internet ;-].
Possible causes/solutions we came up with:
- water is definately the cause, but that doesn't explain while it affects only a part of the launch, and not the rest of the trail..
- we built almost everything on top of existing paths; so the ground is very hard there; is it possible that water drains through the dirt, to end up on the path, where it can't go further, so then just leaves the jump at the kicker?
- dig away a part of the kicker, fill it again with other dirt
- make pathway in front of the jumps a lot higher than the surroundings
- is this normal and should we just be more patient? (bweirk)

Any reactions are welcome!!

 

[Cru Jones]

It could be because those spots don't get as much sun as the rest of the trail. Depending on which way they are facing, the jumps can sometimes shade themselves. We have had that problem at our trails, not on a lip, but a patch that would never dry. Your idea of digging out the mud and filling it with good dirt should work. Then also make sure you have good drainage going away from the areas that tend to stay soft.

 

[jellybeans]

i agree with cru, just when you fill it back in, make sure you get it an inch or so higher off the ground or you'll end up with the same problem as before

 

[demo 9]

take the top 5 inches and replace with new 5 inches of DRY dirt:cru is right

 

[scag]

If you want to get super tech, when you replace the dirt, put some pea gravel under the replaced dirt...that will ensure that it will drain better. Sounds like you got the right idea though...get the drainage started so theres never standing water during heavy rain in the first place.

 

[stino]

thanks for the replies!

@cru: afaik all problem parts are faced to the sun the entire afternoon and get the more or less the same amount of it; but I haven't been there any time of the day so can't tell for sure.

@scag: I really like the pea gravel idea; was already thinking of putting some crushed wood underneath but that would lead to problems after a while as it rots. But a layer of gravel instead of very compacted dirt could indeed make fine drainage

I'll be testing everything out this and next week, I'll let you guys know what happens!

 

[cmc]

low spots tend to accumulate water. when you have a "singletrack" mtb path through the woods, after a while the erosion makes that the lowest spot, and it can become a stream for water flow. that is one reason (as well as mtb tires) that singletrack trails get so rutted out. your jump may be blocking that flow, creating a mudspot right in front of the jump.

SO, you could try to raise the level of the path itself before the jump and dig a trench off to the side so that water is diverted away from the path.

 

[brandonbmx1]

Throwing some old strips of carpet down (hard side up) used to do the trick for me. As long as there is not a puddle of water in front of the jump you can ride on the carpet.