Mountain Biking - 6ft jump

okay, downhilling is not an option for me and my Rocky Mountain ESTX-70, but I would like sume suggestions on a jump Im going to build. I have desingned a 6ft jump that I am going to cunstruct out of plywood and 2x4's, and I want to know if anyone knows how much of a drop my "all mountain racing" or xc bike can take, as this jump will have no landing. I do have a lot of experience with jumping bikes, but I seek help because I am TERIBLE at estimating how much a bike can take. (I ruined the frame on my old trek after about a 9ft drop off) I can easily make the jump smaller, but I would prefer about a 6ft. minimum height. (Im sick of 4 ft. of air off a jump) how much can the frame and suspension take on this specific bike?

6 ft high, across...with tranny, without? If you build trannies you bike will take a lot. A good drop with tranny is like butta for the bike.

Don't know how much. Too many variables. How much have you done on it, how much do you weight, was it amongst the first batch or recent. It might lastit might not. Ride it and find out...really we can't tell you..

Ok Im gonna go ahead and build the jump, because if it was obvious to you that it wouldn't work, you would have told me not to do it. but if there is a good possibility it will work, then its worth it. The other thing I should tell you is that I do not know anything about the jumps built on a real downhill mountain, or a proffesional bike park. the "jumps" I use are either built by me out of dirt or wood, or they are rocks above a dropoff. so I have no idea what a tranny is. If you explained to me how a tranny works Im sure I could build a jump with one. I have been around carpentry for a while.

/TTTT\

is my (pathetic) ascii art representation of a typical tabletop style jump, where the takeoff is the / and the landing tranny (short for transition) is the \. If you land on a downslope, it creates less stress on the bike (and rider). If you plan on building a plywood launch ramp in the shape of a right triangle where the lip is 6 feet high and the landing is flat, you will break something soon.

The reason no one thought it was a bad idea is that no one understands what exactly you are trying to attempt here.

I wasn't questioning the the material used. But are you building a 6 ft ramp to flat? I was just asking because there are several dimensions to a jumps depending on the type. I was trying to figure out what you mean by a "6ft jump"

/TTTT\

is my (pathetic) ascii art representation of a typical tabletop style jump, where the takeoff is the / and the landing tranny (short for transition) is the \. If you land on a downslope, it creates less stress on the bike (and rider). If you plan on building a plywood launch ramp in the shape of a right triangle where the lip is 6 feet high and the landing is flat, you will break something soon.

The reason no one thought it was a bad idea is that no one understands what exactly you are trying to attempt here.

Yep...thats what I was asking :D...

the ramp im building is 6ft. high, 4ft. wide and 8 ft. long. The sides, which are not straight but sloped like a skateboard halfpipe, are constructed out of 3/4 inch plywood. the 2x4's between the 2 sides are 46 1/2inches long and are spaced 8 inches apart. the whole assembly is then covered with 2 sheets of 3/8ths inch plywood, and there is no landing or tabletop.

should I build a landing or tabletop, or will that work?

I would build some kind of sloping landing, to ease the stress caused on the bike and wheels. When you land flat like that, things are going to go wrong i'm sure.

Build a tranny (sloped landing)...softens the stress on the bike

ok ill do that, but it will probably be a dirt landing, as pressure treated plywood isnt cheap these days, this thing is gonna run me up $300! I guess it's better to sped money on wood instead of new bike parts though. like I said, I ruined my old trek on this type of thing. (It was one hell of a jump though, and I have scars to prove it :)

Just set it on top of a hill and use the natural downslope as your tranny / landing. Total additional cost: $0.

Then post pictures, because that will be a pretty big jump.

good idea, maybe 6ft is a little too big though

I'm just going to say use the right tool for the job. In your case, you are using the wrong tool period! I read your other post about your bike being able to handle downhill; I chose to stay out of it. Now I feel the need to say something.

Don't cry to Rocky Mountain when your frame suffers a catastrophic failure and even worse you land yourself in the hospital when because of using the wrong tool for the job it fails, and you are injured.

Your bike is not the right tool for the jobs you want it to accomplish.

Oh why not just get the answers directly from the horses mouth? Here is their contact information. I've worked with them quite a bit and I'm sure they will give you an honest answer.

Rocky Mountain Bicycles
1322 Cliveden Ave.
Delta BC Canada
V3M 6G4

Phone: (604) 527-9993
Toll Free: 1-800-663-2512

http://www.bikes.com/about/contact.aspx

Don't cry to Rocky Mountain when your frame suffers a catastrophic failure and even worse you land yourself in the hospital when because of using the wrong tool for the job it fails, and you are injured.






Listen, I know that you know a lot about freeride, downhill, and jumping bikes, how could you live in southern California and not know those things? But just because im seeking advice here does not mean that I know nothing about jumping bikes.I have an extensive background in carpentry and I have been building these plywood jumps for 5 years, Im not new to this at all. I was just asking how long it would take to wear out an xc bike on a 6 or 7 foot jump, because Im bad at making those kind of judgements. I paid a lot of money for my ETSX, and I choose it because it IS the right tool for the job, It may not work well out on the rockfaces of California, but trust me, Ive taken off 9ft dropoffs, 4ft plywood ramps, and Ive bombed many steep rocky hills. It is the right bike for where I live. I am absolutely NOT questioning your knowledge in any way, and Im not trying to start an argument. I have been an off road enthusiast for about 11 years, riding not only performance bikes but in my truck as well. I have pushed the limits on bikes far worse than the Rocky Mountain I ride now. My ESTX is not garbage and it will not suffer "Catastrophic frame damage" under any of the conditions I ride it on, including jumps.

six6one,



Then why did you ask us if it could handle it? You asked for advise and some very experienced riders gave you advise. Never once did I question your ability to jump or build a jump. I simply stated the fact that you are riding a light weight full suspension XC bike not designed for jumping or downhill. I never said that it was not a good bike. It is a good bike for its intended purpose.



I said that the bike will fail causing the injury. If you don't want to hear our answers then don't ask. I have even provided you with Rocy Mountains toll free number so that you can ask them.



You become defensive with anyone that says anything contrary to what you already have stuck in your head. And that must be that your bike will handle anything you want it to. If this is what you believe then have at it; just dont say we did not warn you first.

yea I regretted sending that right after I did it. I didnt really fully understand what you meant before writing that response. Upon reading that for the first time I thought you had meant that my bike was not a real trail bike and could not take the abuse without breaking. of course that is not what you meant, and I got that about 5 minutes after sending that response. I get angry occasionally, sorry bout that. seriously though I am never gonna be riding the kind of trails that might break the back of my xc bike. some of the trails i ride are extreme, but if you saw them youd understand that it would be pretty hard to wreck that bike on the trails in Massachusetts. especially not that bike, it may be xc, but it weighs in at 39lbs, and im not exagerating. this could be because of the modifacations I have on it, I wouldnt know, I never weighed it when it was stock.

39pnds...holy crap I think that is the heaviest epic around. My bighit only weight 42 with a dual crown fork. Are you sure thats accurate?

Im pretty sure. it was very heavy to begin with, but I switched out the rims and tires within the first week after I pinch flatted both of the tires, and I bent and broke some spokes on the rims. the new rims and tires are more all mountain freeride type. I know that the tires weigh something like 2050 grams they're very serious. I hate those skinny flacid stock tires. Thats the reason I asked you if my bike could handle freeride/DH, is becuase I figured it was an all mountain bike, because its too damn heavy to be xc. the RM website calls it an all mountain bike as well, but thats just the catagory they call it. It doesn't mean too much

i was thinking about posting about the bike earlier, but i didn't want to get into the whole debate over your bike...

rocky mountain's estx series is part of their all-mountain series of bikes, along with the slayer. so i'm sure it can handle a bit of everything...

my fluid weighs around the same - when i bought it stock it weighed in at 36lbs (i'll weigh the bike again soon to see how much it's at now with the upgrades i've made). it's also classified as an all mountain bike and i use it to do pretty much everything - commute, dj, trail riding, drops, jumps... so far it's held up just fine :D .

All this talk about rear suspension reminds me why I went back to a hardtail.

That was smart to go back to a hardtail. This has turned into much more than I wanted it to be. I had a few ideas that I was gonna do, like downhilling and building that jump. I just wanted to hear if other people thought it was a good idea. it turned out to be an argumental mess between me and that guy from california. I would like to say this: Maelstrom, Konarider, and rasheed, you have all been very helpfull. I value and appreciate your input