[dbisers311]

Hi,

I'm currently designing a full suspension frame and am torn between what shock to spec on it. The frame is going to be a single pivot, pivot mid hight on the down tube, ~8 inches of travel. This is going to be more oriented towards freeriding than bombing down really long hills through rock gardens, mainly because I'm going to be riding this bike in urban, on ladder bridges, etc. I want this bike to pedal reasonably well and take the big hits, i.e. possibly 10 feet to flat at some point in the next 2 years. I've heard so many great things about the progressive, how I should be able to tune it so I can eliminate alot of pedal bob, my question is could it take repeated hits like the one I described. My other option is an Avalanche shock, which from all I've heard would laugh at 10' to flat, correct me if I'm wrong about the pedal feel being a little dismal using it though. Input on this will be much appreciated, I'd really like to hear the opinions of people that have rode these shocks.

Thanks

P.S. Being out for 6 weeks with a broken leg really sucks.

 

[Mr. ShockWave]

I don't know both shocks personaly, but from what I know about it you would be happier with an Avalanche than with an 5th Element.
An Avalanche is build to handle more abuse than an 5th Element.

 

[narlus]

"pedal feel" on an avalanche is absolutely NOT DISMAL. it's excellent. makes my DHi pedal way better than my joker.

that said, the DHi is a v. good pedaling design to begin with, but the av shock is a huge improvement over the fox.

 

[DHS]

I have a avalanche on my Disco Volante, and love it. i've done some 8-10foot to flat drops and its saved my ass very well.
but if i were racing i think i'd rather have a 5th element....maybe cause it lighter, not enough feedback on it yet. wait for the new fox shock, looks just like my avalanche.

 

[KonaDude]

You're designing a frame, eh?

How far along are ya?

 

[dbisers311]

Hey,

So far I've got a design in solidworks with everything modeled. Most of this was done by a friend of mine who was designing his, but abandoned the project. He knows what he's doing so I'll probably follow his design pretty closely, just changing geometry and adding a few things, like an integral chainguide and a floating rear brake. The front triangle will be made from straight guage 4130 tubing, just a conventional triangle with reinforcements for the bottom and top of the headtube and a little gusset. The swingarm will be a one peice box section made by welding steel plate. Frame weight with hardware should be somewhere around 10.5 pounds. Right now I'm learning how to TIG weld, construction wont be attempted until I feel proficient to do the job. This bike will mainly be used for freeriding in Rochester, NY which is pretty flat, except for our sick little mountain biking park, which has some very techinical riding with stunts, but none of the downhills lasts for more than a minute. Taking this into account I'm going to design it with a more upright headtube angle and a shorter wheelbase, but this will be adjustable a little with a movable shock position and rear dropouts that will allow for some adjustment in wheel position. I'll post some pictures when the bike is finished. Hopefully this will work out well, If not it won't be such a big hassle to weld a new frame up with modifications after I finish this one, evolving the bike into a really good design, or at lest that's the plan.

Dave

 

[emmaman]

I don't know much about the Avanlanche, but I just tried the 5th on a Bullit and that felt really nice and the Bullit became a whole new bike.
With all those adjustments I can't see why it shouldn't take big hits? Can the Avalanche be tuned just as much?

 

[dbisers311]

I'm pretty sure that the 5th element can be tuned to make the suspension progressive enough to eat up the big hits, but will it blow up. After hearing about every other Fox shock exploding on a big hit this is a major concern of mine, even if the company will replace the shock free it still means the bike is out of commision for a week or so. Has anyone had a progressive break on them?

Thanks for your help

 

[DHS]

hey Dave

i live in Rochester NY aswell. so if you want to feel a Avalanche, or ride for that reason, give a yell back. or a 5th element, my friend has a bullit with one and Towpath bike shop has a V10 coming in next week. so its up too you...

 

[gravity]

Originally posted by dbisers311
Hey,

So far I've got a design in solidworks with everything modeled. Most of this was done by a friend of mine who was designing his, but abandoned the project. He knows what he's doing so I'll probably follow his design pretty closely, just changing geometry and adding a few things, like an integral chainguide and a floating rear brake. The front triangle will be made from straight guage 4130 tubing, just a conventional triangle with reinforcements for the bottom and top of the headtube and a little gusset. The swingarm will be a one peice box section made by welding steel plate. Frame weight with hardware should be somewhere around 10.5 pounds. Right now I'm learning how to TIG weld, construction wont be attempted until I feel proficient to do the job. This bike will mainly be used for freeriding in Rochester, NY which is pretty flat, except for our sick little mountain biking park, which has some very techinical riding with stunts, but none of the downhills lasts for more than a minute. Taking this into account I'm going to design it with a more upright headtube angle and a shorter wheelbase, but this will be adjustable a little with a movable shock position and rear dropouts that will allow for some adjustment in wheel position. I'll post some pictures when the bike is finished. Hopefully this will work out well, If not it won't be such a big hassle to weld a new frame up with modifications after I finish this one, evolving the bike into a really good design, or at lest that's the plan.

Dave

so you're just gonna buy some tubes, measure and cut them, and weld em all up eh? no offence, but i think you'll find it's a LOT more complex than that, even just to get a head angle within 2 degrees of what you want is very hard. all parts on bikes are extremely precisely measured, you have to be a very skilled machinist to do it all properly.

i could be wrong tho...... however KD has invested a huge amount of time and money (how much money, he can tell you if he wants, but it's TONS) in developing his frame, and it's not even done yet. then you gotta buy parts etc for it.....

i would really like to see KDs bike when it's done tho..... should kick arse!

 

[KonaDude]

Originally posted by gravity


so you're just gonna buy some tubes, measure and cut them, and weld em all up eh? no offence, but i think you'll find it's a LOT more complex than that, even just to get a head angle within 2 degrees of what you want is very hard. all parts on bikes are extremely precisely measured, you have to be a very skilled machinist to do it all properly.

i could be wrong tho...... however KD has invested a huge amount of time and money (how much money, he can tell you if he wants, but it's TONS) in developing his frame, and it's not even done yet. then you gotta buy parts etc for it.....

i would really like to see KDs bike when it's done tho..... should kick arse!

You're definitely right. This has so far been a huge process for us getting everything we need. We've sourced custom tubing, pivot hardware, shocks, hubs, all the parts we need to check for fit, and we hire specialists to do our work. Even after 2 years of work, I have really nothing except a pile of machined parts to show for it!

I probably shouldn't disclose company spending, but I'll say it's between 10 and 50 thousand dollars spent so far. Probably on the low-side of a yearly family income. There will be more spending down the road too, we're only part way through.

But, as you go along you'll discover the subtleties of frame design and manufacture. I wish you luck, and look forward to seeing some pictures!

Thanks, Gravity, for the comments! I am really looking forward to it myself, hopefully lots of progress will take place in the next few weeks. I'll start taking pictures as we move along and post them up.

 

[dbisers311]

Lets clear some things up.

The original design was done by a riding buddy who works as a mechanical engineer. The frame with a fox shock and all hardware right now, which includes a Mr. Dirt fork, 24 and 26 X 3.0 Gazzis, MRP chainguide, raceface cranks, etc. has been modeled in 3D using SolidWorks 2001+ and interferences have been checked and fit up. FEA analysis has been done on the front triangle with test forces at the headtube, swingarm pivot, and shockmount. The test forces were 3 times the max expected force. FEA hasn't been done on the swingarm yet but it is very beefy and should probably be fine. Right now, without a floating disc the frame is designed to use the dropouts/rear hub/axle from a kona stab primo. The main pivot will use standard cartridge bearings, big mothers though. As I'll probably change the angles and wheelbase and shock I'll have to play with the shock pivot points and swingarm ratio to get the rate for the speced shock.

As for construction I'm a Computer Engineering student at the Rochester Institute of Technology in Rochester, NY. I'm also on the Mini-Baja team, which designs, builds, and races a one seater off road race car. RIT's team is one of the best in the country. The frame of the car is built from 4130 tubing and tig welded. The brake system, throttle, shock mounts, gear reduction box, hubs, and all other little bits are machined in the full machine shop we've got, including a TIG welding rig. Though the frame is not designed to use any CNC crap we've got that too and could get stuff made here. I also have my teamates that have designed and built this car to go to for advice and help building it.
Jigs will be made for the front triangle and swingarm for welding, and I have the resources to make very precise miters for the tubing.
Another riding buddy, the good John Frame, founder and CEO of Draco Industries, is currently making some lexan bashguards with a full guide in the works. Very soon he's have 5 super burly steel hardtails welded up, we'll see how this goes, it'll give me a look at how his design works, points to check out etc.
I'm not sure yet about the floating disc or integral chainguide, but there's contigencies for that right now. I'm not sure how well this will work but I'll most likely initially just clearcoat the bare steel, should look pretty bad ass. I should be able to strip off the clear coat and weld more tabs or grind **** off as far as putting a integral chainguide in.
This is gonnna be a pretty down and dirty frame, single pivot, standad straigh guage 4130 steel tubes and plates from aircraft spruce. After some time spent on this I should be able to build
a new swingarm, or front triangle, or both, to implement improvements.
As I haven't built a frame before mistakes could definietly happen, but I'm not in a huge hurry, I think I have a good design now that will receive some refinements, and I certainly think I have knowledgeable people to go to for assitance.

DHS, you know who I am, dave on the black hardtail, i live right by the jumps. haven't seen your new disco yet though.

What are all you guys spending time on this site anyhow, I've got a broken leg right now, you should be out riding.

Dave

 

[dbisers311]

Again, the original purpose of this thread was to see if people have had their progressives blowing up on them on the big stuff. If I have doubts of its strength after this I'll most likely get an avalanche. A friend of mine has the new bullit, but he hasn't done anything real huge yet on it. So any help will be realy appreciated.

Thanks,
Dave

 

[DHS]

oooooohhhhhhhhhhhhhh

makes much more sense there

hi dave.......

anyway, go avalanche.

um, what stroke you going to use?

 

[DHS]

also for a better chain line, you should copy the trek diesel chain guide design, road one last week at whiteface. works very nicely with single pivot

 

[KonaDude]

Originally posted by dbisers311
Lets clear some things up.

The original design was done by a riding buddy who works as a mechanical engineer. The frame with a fox shock and all hardware right now, which includes a Mr. Dirt fork, 24 and 26 X 3.0 Gazzis, MRP chainguide, raceface cranks, etc. has been modeled in 3D using SolidWorks 2001+ and interferences have been checked and fit up. FEA analysis has been done on the front triangle with test forces at the headtube, swingarm pivot, and shockmount. The test forces were 3 times the max expected force. FEA hasn't been done on the swingarm yet but it is very beefy and should probably be fine. Right now, without a floating disc the frame is designed to use the dropouts/rear hub/axle from a kona stab primo. The main pivot will use standard cartridge bearings, big mothers though. As I'll probably change the angles and wheelbase and shock I'll have to play with the shock pivot points and swingarm ratio to get the rate for the speced shock.

As for construction I'm a Computer Engineering student at the Rochester Institute of Technology in Rochester, NY. I'm also on the Mini-Baja team, which designs, builds, and races a one seater off road race car. RIT's team is one of the best in the country. The frame of the car is built from 4130 tubing and tig welded. The brake system, throttle, shock mounts, gear reduction box, hubs, and all other little bits are machined in the full machine shop we've got, including a TIG welding rig. Though the frame is not designed to use any CNC crap we've got that too and could get stuff made here. I also have my teamates that have designed and built this car to go to for advice and help building it.
Jigs will be made for the front triangle and swingarm for welding, and I have the resources to make very precise miters for the tubing.
Another riding buddy, the good John Frame, founder and CEO of Draco Industries, is currently making some lexan bashguards with a full guide in the works. Very soon he's have 5 super burly steel hardtails welded up, we'll see how this goes, it'll give me a look at how his design works, points to check out etc.
I'm not sure yet about the floating disc or integral chainguide, but there's contigencies for that right now. I'm not sure how well this will work but I'll most likely initially just clearcoat the bare steel, should look pretty bad ass. I should be able to strip off the clear coat and weld more tabs or grind **** off as far as putting a integral chainguide in.
This is gonnna be a pretty down and dirty frame, single pivot, standad straigh guage 4130 steel tubes and plates from aircraft spruce. After some time spent on this I should be able to build
a new swingarm, or front triangle, or both, to implement improvements.
As I haven't built a frame before mistakes could definietly happen, but I'm not in a huge hurry, I think I have a good design now that will receive some refinements, and I certainly think I have knowledgeable people to go to for assitance.

DHS, you know who I am, dave on the black hardtail, i live right by the jumps. haven't seen your new disco yet though.

What are all you guys spending time on this site anyhow, I've got a broken leg right now, you should be out riding.

Dave

Well, that looks pretty cool! I'm interested to see how it works out for you, and wish you luck with it in the future. You seem very prepared and have a good backing from the sounds of it.

As for the shocks. 5th Elements are getting good reviews from the racers who've been testing them, apparently. I've heard of spring collars snapping. They originally used cast aluminum, although new ones are apparently shipping with machined aluminum ones that should not fail.

Avalanche shocks have been on the market for some time now and I think have been proven more than worthy! Every single one gets custom set up to the bike and rider, and you can't beat that. Now, some other people who've ridden them say they're better for big hits and freeridish stuff, but it all depends on how it's tuned. Tell Craig to tune it for pure racing, it'll be good for racing. Even MENTION drops, and the tuning gears towards freeride.

You've got time to investigate, so watch as things unfold.

 

[Dirt rider]

well I think dbisers311 and konadude should compeate in a deathrace

Ive seen KD and Dhdecenders frame design on paper and a ton of CNCed bits at Hammerfest ( im still mad I didnt hold the avalanche shock).

it will be great

steel vs. Aluminum

complex linkage vs. single pivot

east vs west

canada vs U.S

 

[gravity]

Originally posted by dbisers311
Lets clear some things up.
...
yadda yadda
*clears things up*
yadda yadda
*cool pic shown*
...

right, well you're obviously further into it than i originally interpreted, my bad. if you really CAN get all that stuff done well, props to you. what i was sorta thinking was that if you don't know how to weld or are still learning how to do it, you will probably not get a good result if you weld it up yourself. TIG welding is very difficult too, i've tried it, and compared to MIG or arc or oxy, it is much harder. i would only advise (who am i to advise, but hey) that you get someone who is REALLY REALLY good at welding to do it..... otherwise it might not be strong enough/precise enough and so on.

the frame design looks good, but i don't really understand the point of box-section bits...... do you mean monocoque, or just box-section?

 

[dbisers311]

Hey all, forgive me for my bitchy attitude from the last post, a fit of "who could doubt me!" to the old ego. Anyway, DHS I'm probably going to be using a 2.75" or 3.0" stroke shock since everything I've read said that the smaller the ratio the better, and I'm going to be using a slightly shorter swingarm than most people probably, still have to get the pivot geometry set up for rising rate for the avalanche if used. I read somewhere that you should have the frame design with a more linear rate linkage for the suspension when using the Progressive, that it has a more rising rate than a normal shock.
Gravity, I guess I've never really been properly informed to the specifics of monocoques, i can describe the swingarm though. Each of the totally flat sections will be cut from a peice of steel plate. the more mild angles, like at the top of the side peices, will be bent into the metal, that is probably where I'll have most trouble in fabrication. After the 6 or 7 peices are cut out they will be welded together into a closed wishbone shaped box for the swingarrm, after FEA I might put angle iron type peices on some of the butt joints. This design offers the most strength for weight and space, i.e. tire clearance, as long as it doesn't develop a wrinkle it is really strong, once it does wrinkle though you're screwed, the whole thing will just fold up, plan is for that never to happen though.
As far as TIG welding goes I was told by the guy I'm learning from that I'll probably need about 100 hours total for me to get to the point of me making trustworthy welds for the bike. Right now I'm still practicing running beads on scrap plate, trying to get the right heat penetration.
KonaDude good luck with your design, hopefully you get it done soon and built and its awesome. As for me, the goal is to have a bike before winter most likely, as that is when I've got the time for this venture.

Dave

 

[dbisers311]

Actually that's an older pic, the down tube is bigger diameter now, so that tube that run through it for the pivot only sticks out a tiny bit on each side. The big downtub also is there to resist the twisting forces between the pivot and shockmount.

 

[crazybastard]

I would look into avalanche and romic too they got some sick shox
as about building the frame that is one of those practicly impossible tasks.
so good luck send me a pic when its done

 

[DEMON]

looks really good i,m a longtime rider and fan of single piviot design frames , the cromo is a good start for a prototype , you don,t need to heattreat the frame after welding , and the material does not move around as much as aluminum does , when you go to weld your frame don,t forget to purge the frame with what ever gas you are using to sheild the arc ( argon, co2, etc.) a friend of mine and ex-coworker has 25+ years as a A class tig welder and says purging with make a big difference in the weld and penitration .

as for a shock i would give the 5th element some more time in the hands of the public ( some people are having problems , besides the spring collars breaking ) i would go with a AVALANCHE or ROMIC both of these companies will help in getting a shock best suited for your design and requierments .

it,s good to see people designing and building their own bikes , in the past 2 weeks i,ve seen to designs that were owner design and built , one was a single piviot design ( the guys works at JOHN HENRY in northvancouver , and the other design was to hard to describe , it was a design i,ve never seen before , and i did not get a close look at it , the designer was a young from ontario or quebec , i saw it at whistler when i was up there for the JOYRIDE competion , maybe BROCK or some of the other ,s got a shot of it or had a better look at it .

anyways keep us informed on your progess and try and post some images on the dh/ds forum as well

 

[dbisers311]

After what I've heard so far I think I'm leaning towards the avalanche shock right now. My cast is coming off on wednesday, I think I'll try and test out the avalanche on DHS's disco sometime soon, and my buddy has a new bullit so I'll have to do testing. Avalanche sounds like a really standup company that can tune the shock exactly the way it needs to be, plus its indestructible.

DEMON, I've been told that you don't need to backpurge when welding steel, a debate went on about it on the framebuilders email list a while back, I'll have to check it out. A little money on argon will certainly be worth it to have good welds on a bike i'm gonna be hucking.

Thanks for all your help people

If someone wants to try and defend the progressive, do it now.

 

[DHS]

Negative Captain

 

[DEMON]

Originally posted by dbisers311
After what I've heard so far I think I'm leaning towards the avalanche shock right now. My cast is coming off on wednesday, I think I'll try and test out the avalanche on DHS's disco sometime soon, and my buddy has a new bullit so I'll have to do testing. Avalanche sounds like a really standup company that can tune the shock exactly the way it needs to be, plus its indestructible.

DEMON, I've been told that you don't need to backpurge when welding steel, a debate went on about it on the framebuilders email list a while back, I'll have to check it out. A little money on argon will certainly be worth it to have good welds on a bike i'm gonna be hucking.

Thanks for all your help people

If someone wants to try and defend the progressive, do it now.

a friend i meet while going to BCIT for my machinist apprenticeship used to build Ti frames for mtb use and they back purged all their frames, but it,s like most things in life some do and some don,t , i guess it wouldn,t hurt to try , from what i,ve been told the penitration weld will look even better than the weld on the outside due to the fact that there is no air to contameinate the weld .

good luck and keep us informed.

 

[draco]

so dave, still going to do it? we've got those plans for the big bike still... and The Vacancy Crew has just begun theirs... I believe it to be a large messy project, but I've been hired to head it up I guess.... So it better work!

for any and all catching up, those five hardtails came out beautifully, and have held up to a RIDICULOUS amount of abuse. in fact, now we are fighting to see which will last longer: frames or body parts.

 

[Repack]

I've never ridden an Avy, but the 5e is great. The rebound damping is awesome for drops. It doesn't unload on you all at once throwing you over the front (think Bender ). It works well for sucking things up. The same aspects of the shock that make it good for racing and drops is what makes it a poor dirt jumper, if that helps explain it. I weigh 200+ and have had no issues. Why not go to a race and take a poll? Did I read that you live in NY? If so, go to PKill next weekend.

 

[CTR]

db, it sound like your trying to build somthing simlar to this

http://www.hoodbikes.com/mussle.html

best of luck with your bike, i like the idea of stress testing everything on computer then beating the crap out it in real life to fine tune it, seems like lots of good products start that way.

anychance of a updated design pic?

 

[draco]

well, we started ona frame today similar to what dave and I had discussed. its a mid to high single pivot... shady and fun. anyone going to plattekill weekend of the 12th will get a peek

 

[Rustmouse]

Well, being a big guy with a bullitt (225 lbs) and the fifth element, I can say I've not been able to do anything wrong to it.... including accidental 10' drops to flat....

I would say longer stroke is better, personally... a shorter stroke shock would have more mechanical leverage against it than a long one. (if the rear end moves 8 inches and the shock only moves 2, that's a 4:1 ratio... if the rear moves 8 inches, and the shock moves 4, then it's only 2:1) if you think about it in terms of weight, if you drop 200 lbs on the rear wheel, on a 4:1 ratio, that's 800 lbs on the shock! (I'm not sure about the math on a bike, but when climbing, a person falling 10' on a static line can generate 1000lbs of shock load on a rope!)

using that logic, I'd want the shock as close to 1:1 as possible, since materials being what they are, they don't have to try that hard if there's less load.

Last, I would say to go for a shock that is designed as a "Big Hit" shock. The fifth element is an awsome piece of engineering, but I don't think they designed it around big hit freeriding (even though I'll bet it would perform admirably) With all the engineering in it, I'm pretty sure it's not gonna do as well with the huge overpressure you're talking about...

 

[draco]

yo rust.

thats the basic idea, but that brings into light a need for shocks with as much stroke as travel! most shocks are capable of 3:1 ratios. lower is better, yes. but within current shock standards (2.5-3.5" strokes) your max travel ends up being 10.5" at 3:1.

now for example. i designed a frame with 6" travel. uses a 3" stroke shock. 2:1 ratio allows for super soft spring, and is awesome to tune. downside: shock needs to be effectively mounted halfway down the swingarm... hard to do.

but yeah, i agree!