Burms oh Burms

RiLiZe

Likes Dirt
hey Guys,

i am currently building a short downhill track at my farm and it only has 1 berm on it. does anyone out ther know how to build good, strong and stable berms???

thanks.
 

gordonvale94

Likes Dirt
Hey mate.

In my experience with building berms the best thing to do is find some logs and lay them on the ground in the shape of your berm as a sort of guide, then get some star pickets or large wooden stakes, bang them behind the logs you've set down and start building up more logs as fill, the stakes should keep them from falling, so you don't have to use so much dirt. Once you have built up enough fill for the berm lay some grass, leaves or twigs over any holes or gaps in the berm (trust me this helps, bulding a berm can take forever if the dirst keeps falling through the gaps) and start chucking on dirt on. It will be soft at first but after you compact it, wet it and ride over it, in time it will set and become rock hard (the time in which this takes can vary from dirt to dirt). Just remember if the stakes you used weren't treated then replace them every few months otherwise you might be unlucky enough to hit a rotten berm and go straight throught it!

Sorry for my rambling on.....

Cheers Kyle
 

dcrofty

Eats Squid
Kyle don't take this the wrong way but I'm going to have to disagree with a little bit of what you said there. Wherever possible try and avoid putting any organic material in your berms, so no grass twigs etc. The organic material will eventually rot and your berm will slump and organic material can also prevent your soil from binding and compacting properly.

If you want to build the best berms you need rocks and dirt, nothing else. It takes a lot more hard work and a lot more time but you will get a better result that will last a lot longer and take less to maintain. If you have to use timber in the berm (sometimes you gotta so don't think you cant) then try and make them as big as possible and fill all the gaps etc with dirt and rocks.

The pics below show some of what I mean, I've posted them a few times before but they show what I mean. This berm took about 90 hours to build. Good quality stuff takes time but lasts for ages.











 

trav

Likes Dirt
The best method to builld berms is to use only soil. Try to build it out of one type of soil so it will bind and hold a consistant shape.When you think your berm is big enough double it's size and you should be on the mark.Give it a nice thick back with a flat top edge ,don't make it pointy some one will ride straight through it.Compaction is the critical ,so get it as hard as you can before you ride it.

We use this method at the You Yangs with excelent resaults.
 

gordonvale94

Likes Dirt
Hey Dcrofty.

I don't take any offence to people giving helpful info, and thanks for yours but unfortunately where I build there is limited wood that I can use, the BIG logs are simply too heavy and often packed with white ants so i am forced to use small logs which as you said don't last long but I can't go around cutting down huge trees. But the rocks are a very good idea, I guess I was just too lazy to get them.....Thanks for the info.

Cheers Kyle
 

frozenhole

Likes Dirt
It all depends on the slope of the terrain you're buidling your berms on. If its relatively flat and not so steep you could get away with pure dirt.

But the steeper it gets its better to build a nice retaining wall out of rocks. It may seem like a mission collecting rocks from the surrounding area but its really worth it. There's a nice sense of pride when you finish a well built berm, you can stand back and admire the hard work you put it and know its going to last. No shortcuts!

Logs rot out pretty quick from my experience.

As for the curve of the berm I guess that just comes down to experience, a bit of trial and error and plenty of testing which is half the fun of it!

Cheers,

Paul
 

thecat

NSWMTB, Central Tableland MBC
Digging them into the ground is also a method, so long as you take into account water build up.

On berms where the exit is lower than the entry this isn't an issue so long as there is a drainage channel near the exit to get water off the track. In flatter berms a drain out from the lowest point can be used. I've used 6" polly pipe but find that after big rain it tends to still clog and you need to ram a stick up through the pipe to allow the water to drain quicker.

The idea is to dig into the ground about half the high of the berm. What you dig out then goes on top to build up the top half.

if done right the bottom of the berm is completely supported as there is solid earth behind it. The top half can be built up with logs pinned in place by surveyors pegs (do not use metal star pickets) or rocks and then covered in the dirt you dug out in the first place. By widening the inside you give more options in how to hit the berm and get more dirt to batter the back side to make it even more solid.


You can see that the top half of the berm below is completely dug into the ground. Because of the way the hill drops away near the exit the last bit has had to be supported up with logs. In an ideal world we would have used much bigger logs, like what Crofty points out, and the back side battered up as well.

you'll note that even where the logs are used the inside has been dug in to give that positive camber the whole way across the trail. That way if you stay low in the berm you have solid earth to rail against.
 
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Jervis

Likes Dirt
Pure dirt works well. Its not that hard, just dig, compact, dig, compact, dig, shape, compact...

These are the top two berms at my mates and my trails- berm which ends in a slight bump, down a roller into next berm, which shoots you into the first double.



 

DjRyde

Likes Dirt
Use good stronge solid rocks that's the best and strongest way. Don't use natural materials etc wood, because it will just rot away
 

RiLiZe

Likes Dirt
Pure dirt works well. Its not that hard, just dig, compact, dig, compact, dig, shape, compact...

These are the top two berms at my mates and my trails- berm which ends in a slight bump, down a roller into next berm, which shoots you into the first double.



those are nice some nice berms there mate...
thanks everyone for the info
 

Jervis

Likes Dirt
Good lord Fergus. Those are fantastic.
Its actually Jervis, hence the username change;)

More photo's to come, we've built another double, big roller, double, pumps, and starting another huge berm to swing into a line of massive doubles. I'll start a thread I suppose.

No worries RiLiZe! Hope it helps.
 

DHD Jr

Likes Dirt
The pics below show some of what I mean, I've posted them a few times before but they show what I mean. This berm took about 90 hours to build. Good quality stuff takes time but lasts for ages.
Or you could just build a pretty decent one in 3 hours, maintain it ocassionaly and you could spend the spare 80 hours riding it.
 

Jervis

Likes Dirt
Bad news, the above trails I posted got demolished :( I got a few photo's of some new stuff we built there days before it was levelled. Will post those later in a thread of our new place (below), private property this time!

This is another form of berm. Mellow, long and leading you into a sender up ramp.

 

Bretty.

Likes Bikes and Dirt
Oh that sucks Jerv. At least this time council can't touch 'em!

Dirt looks sooooo good to work with.
 

MTBalltheway

Likes Dirt
!

My mates and I have made a few berms over the last few months.

We mainly build them with a rock layer (shapes the berm), and then wack on some dirt over the top.

We have tried doing it with branches with one of the berms, it is good, but it moves quite a bit.

I definatly prefer the rock and dirt berm!

Good luck, hope that this helps.
 

dcrofty

Eats Squid
Or you could just build a pretty decent one in 3 hours, maintain it ocassionaly and you could spend the spare 80 hours riding it.
Very true.

I was actually getting paid for that work I posted though so the 90 hours was a good option :)
 
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