# "Boxing" Doubles and Table Tops



## JMH (Feb 23, 2005)

Would love to see some examples of boxed jumps. Our local DH trail just received a LOT of pressure-treated wood from the city and we would like to make something that looks good and lasts.

Any advice? Horror stories? Clever building techniques?

Thanks!

JMH


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## cmc4130 (Jan 30, 2008)

JMH said:


> Would love to see some examples of boxed jumps. Our local DH trail just received a LOT of pressure-treated wood from the city and we would like to make something that looks good and lasts.
> 
> Any advice? Horror stories? Clever building techniques?
> 
> ...


just don't do anything like this:
https://jester777.files.wordpress.com/2007/10/p9271027.JPG

use the wood for wallrides and build jumps with only dirt !!!!


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## Hardtails Are Better (May 4, 2005)

I haven't used pressure treated wood for anything, just split logs and rocks and dirt, but here are some thoughts.

-It's tempting to put the lip too close to the back of the box, like the one in the picture above. Don't. It's way easier to keep the lips in good shape if you build them like you would a normal dirt jump. Build them up out of the box a bit, and leave a decent amount of dirt behind the lip. I have had pretty good success using a box and fill of rocks/ logs and dirt to cut down on digging though. Just make sure you get enough dirt in there to pack it well.
-If I had a pile of pressure treated wood like that I'd be tempted to turn a bunch of it into ladder drops. I'm not finding a good picture right now, but we've built a bunch of pretty fun ladder drops. Couple decent sized logs for stringers, couple more for supports, some cross bracing, in your case some pressure treated wood for the deck, a dirt landing, bam.


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## cmc4130 (Jan 30, 2008)

maybe it's just my bmx / mtb dirt jump background talking . . . but i really don't think you need to make a box to hold dirt to contain a launches or landings. well packed clay holds its shape pretty damn well. the lumber will just get exposed by erosion and then be dangerous to land on if you bail or come up short. metal rods are a terrible idea.

sides of jumps don't have to be perfectly vertical. all dirt has a tendency to go mountain shaped. kind of pyramid like. just pack them up at angle. these are really well done:










a 2X4 is great for packing clay. see beginning of this video. this is a freeride-ish flat launch we built to make a mellow step down for a fun sesh. i just stacked logs then threw dirt on--some people use only dirt with no logs. clay has to be moist but not wet/muddy in order to pack. a day or two after a good rain is great . . . or you can sprinkle every wheelbarrow load of dry dirt with a plant-watering jug as you go so that when you're done it's ready to pack.


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## Hardtails Are Better (May 4, 2005)

cmc4130 said:


> maybe it's just my bmx / mtb dirt jump background talking . . . but i really don't think you need to make a box to hold dirt to contain a launches or landings. well packed clay holds its shape pretty damn well. the lumber will just get exposed by erosion and then be dangerous to land on if you bail or come up short. metal rods are a terrible idea.
> 
> sides of jumps don't have to be perfectly vertical. all dirt has a tendency to go mountain shaped. kind of pyramid like. just pack them up at angle. these are really well done:
> 
> ...


That's awesome if the dirt you've got packs well, but ours is so full of rock it doesn't. Boxes help a lot for that.


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## FM (Apr 30, 2003)

Are you talking about... like this?


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## WaveDude (Jan 14, 2004)

If you've got the dirt--all dirt helps. If you've got [email protected] dirt (rocks, sand, etc...) use that as the base and fill and cap with the good stuff. 

I agree to not making the sides and backs straight up and down--a few have been re-built like that on our trails and they need constant re-stacking. Before they were boxed and lasted lots longer. Also agree to build "outside" of the box to get your lips dialed and also make them case-able (it's going to happen and wood hurtz).

Best idea I've had is to weave old car tires together as the "box". Never tried it but they'd last forever and wouldn't be as harsh to run into as lumber.


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## JMH (Feb 23, 2005)

I guess I should clarify... I know boxes aren't necessary for jump building, the city would like something that looks permanent and have requested it. I do dig at the local DJs quite a lot and can shape a mean lip, but that's not what they're looking for, nor do they want anything that looks like it was hastily constructed or wont hold up. We don't have nearby logs, so they bought us wood.

Makes sense about not trying to contain the entire lip/landing in the box. A good tip.

I was hoping maybe someone might have built a few sexy-looking ones and have pics to share. :thumbsup: 

JMH


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## ebxtreme (Jan 6, 2004)

Jordan,

There are a few in this thread. Quite a few of the new jumps at Duthie are getting this treatment.

http://forums.mtbr.com/showthread.php?p=6627913&posted=1#post6627913

Cheers,
EB


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## cmc4130 (Jan 30, 2008)

ebxtreme said:


> Jordan,
> 
> There are a few in this thread. Quite a few of the new jumps at Duthie are getting this treatment.
> 
> ...


I am stoked on that thread. I will try to make it there this summer (trying to plan a Seattle/Vancouver/Whistler trip). Spot looks awesome and it looks like a fun scene.

Okay. . . this is with 1000% respect to the builders and I don't want anyone to take it as 'criticism', it is just for discussion in a thread on Trail Building techniques..... 
. . . I think it's sketchy to have log jutting out end-wise like on the landing in the first pic. Much better to have them going sidways so an even surface and round edges are exposed. Even better is to completely cover with more dirt so logs are not exposed at all.
Once again, not criticsm. Everyone has their own style of building.


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## highdelll (Oct 3, 2008)

cmc4130 said:


> just don't do anything like this:
> https://jester777.files.wordpress.com/2007/10/p9271027.JPG
> 
> use the wood for wallrides and build jumps with only dirt !!!!


Honest question as a jump building noob, but could someone point out what's the matter with this jump?

thx...


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## cmc4130 (Jan 30, 2008)

highdelll said:


> Honest question as a jump building noob, but could someone point out what's the matter with this jump?


well the main thing i was thinking is that at some point one of those metal rods will come loose, someone will manage to impale themselves on it.

BTW, no offense to anyone involved with building trails or jumps. I respect anyone out there making shlt happen.


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## ebxtreme (Jan 6, 2004)

cmc4130 said:


> Okay. . . this is with 1000% respect to the builders and I don't want anyone to take it as 'criticism', it is just for discussion in a thread on Trail Building techniques.....
> . . . I think it's sketchy to have log jutting out end-wise like on the landing in the first pic. Much better to have them going sidways so an even surface and round edges are exposed. Even better is to completely cover with more dirt so logs are not exposed at all.
> Once again, not criticsm. Everyone has their own style of building.


Despite seeing a lot of activity, Duthie isn't officially open yet (may 22nd) , so a lot of the items you point out are likely to be tweaked before that date for risk management. I'm not building there, but a lot of good buddies are doing this work....the thread just illustrates how you can box in jumps. Black Rock is another good example.

EB


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## Largextracheese (Feb 4, 2004)

Here's a few we built.


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## Jim Z in VT (Sep 9, 2007)

highdelll said:


> Honest question as a jump building noob, but could someone point out what's the matter with this jump?
> thx...


I'd guess the high end of that one will collapse in no time...nothing supporting the lip. There should be a "back slope" beyond the lip.


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## jpculp (Jul 11, 2009)

Build wooden lips with the wood and then build a normal landing out of dirt. like some of the ones above. That way no one will destroy the lips.


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## cmc4130 (Jan 30, 2008)

jpculp said:


> Build wooden lips with the wood and then build a normal landing out of dirt. like some of the ones above. That way no one will destroy the lips.


right on !

this is actually the approach a lot of professional bike parks are taking.


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## Trail Ninja (Sep 25, 2008)

cmc4130 said:


> right on !
> 
> this is actually the approach a lot of professional bike parks are taking.


Did you read the date? 
Almost time the replace the wood now.


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