# The Obsession (tons of pictors)



## c.o.d51 (Nov 7, 2005)

For one reason or another I didn't post this up here. Anyways, check it out.

So this is the frame my buddy has been designing for about two years now. Yup, two years. Here are the fully rendered CAD images, and I'll update this thread as the frame gets built. He also just picked up a nice new Miller Synchrowave 200, so TIG rocks. He's having a ton of parts machined right now, so I'll post those up in about a week. Any questions, and I'll do my best to answer for him. Anywho, the pics:




























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Oh, and here's a quick vid of the suspension.



_Hi everyone, I thought this would be a good time to chime in. I am the designer and builder behind the obsession. My friend posted this thread for me because I usually stay off of forums.

I will talk about the concept behind my design. As you know it is all 4130 steel TIG welded. The rear suspension is my own design and it represents about a year and a half of suspension designing.

The best way I can describe what I am trying to achieve is to compare it to a fork. When you push straight down (vertical) on your fork and try and compress it, it has much more resistance than when you hold your front brake and push in the direction of the fork travel.

What this means is that when you sit down on the bike the rear suspension remains firm and stable, but when you encounter a square edge hit the suspension "frees" up and allows the wheel to move over the obstacle rather than hitting into it.

Depending on the direction of the force that the rear wheel encounters the leverage ratio actually changes. When the bike hits a square edge hit and the force of the impact is in the direction of the axle path the leverage ratio increases (falling rate) and then becomes linear. This means that the velocity of the shock shaft decreases which should reduce the effect known as "spiking" felt during high-speed impacts.
When the rear suspension encounters a vertical force from a drop the leverage ratio drops (Rising Rate); giving the suspension a very progressive fell and increasing the bottoming resistance.

As for the rest of frame: All tubing is 4130 Chromoly and the linkage plates are 6061-T6 Aluminum. Bearings are 28mm OD EnduroMAX._

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Here are some updated screen shots of the frame:




































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OBSESSION BIKES said:


> The program is SolidWorks student edition.
> 
> I have the first set of build pictures and there is much more to come. Last week a spent about 40 hours at the lathe machining parts for the bike as well as doing some welding.
> 
> ...


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A.R.K. said:


> Ok so here it is. The latest build pictures. I still have lots to do, and I will continue to post pictures and progress until I have a fully built up and tested bike. I still have to weld the upper and lower pivot on the front triangle, but this is what I have so far.
> 
> 
> 
> ...


More pics coming too...


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## c.o.d51 (Nov 7, 2005)

Front triangle is pretty much done with the exception of the shock mount, so here we go:








































































The creator:


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## c.o.d51 (Nov 7, 2005)

A.R.K. said:


> Six of the eight parts came back from machining yesterday. I was fortunate enough to be able to oversee the entire machining process and watch exactly how fixtures were used and how the parts were cut. Hopefully that will pay off if and when I have my own CNC machine to make the parts. Right now I am looking for a small CNC mill that I could actually make payments on (maybe a Tormach PCNC 1100).
> 
> Pictured Below are the lower links, yokes, and dropouts. More to come soon....


More to come...


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## c.o.d51 (Nov 7, 2005)

And how it sits as of right now:



A.R.K. said:


> It coming! There is still a LOT of work to do in order to get it ready for the fast approaching season, but this is what I have so far. I still have to weld rear caliper mount, ISCG tab and a few other things.
> 
> So far I am happy with how it is coming out considering I had no JIG for the rear triangle!!!! The front and rear wheels are aligned and run true, so i am happy.
> 
> Also had a chance to feel the suspension and my initial reaction is that it feels really good. It is very stiff when you sit on it, but if you really put some force into it is "opens up". I cant tell you how it actually preforms until I have it built up fully. You will also notice how big it looks, until I stand next to it. Its going to be a racer for sure!


I'll keep this thread updated!


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## Rb (Feb 28, 2007)

some of the most ballinest of the baller work I've ever seen..


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## 08nwsula (Oct 19, 2005)

that is really amazing, are you going to powder coat the frame?


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## DHidiot (Aug 5, 2004)

Good looking geomety. It reminds me a tiny bit of the PDC 825, but the shock mount is slightly different. I've always wondered why someone doesn't experiment a little more with different mounting options with the traditional Karpiel/Parallel link design.

The physics behind that rear end behavior he outlined aren't 100% clear, but it's sure interesting. It sounds like he just gave the dumbed down version for everyone to get the idea of, but I'd be very curious to see or hear all the little mechanics behind it.


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## c.o.d51 (Nov 7, 2005)

DHidiot said:


> Good looking geomety. It reminds me a tiny bit of the PDC 825, but the shock mount is slightly different. I've always wondered why someone doesn't experiment a little more with different mounting options with the traditional Karpiel/Parallel link design.
> 
> The physics behind that rear end behavior he outlined aren't 100% clear, but it's sure interesting. It sounds like he just gave the dumbed down version for everyone to get the idea of, but I'd be very curious to see or hear all the little mechanics behind it.


Yeah, that's the dumbed down version. I'll see if I can get a hold of him later tonight for the better, far more confusing version

It's probably going to get some form of red powder coat.


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## cummings (May 21, 2005)

thats crazy. how much travel. sorry if you mentioned it, i didnt read all the words..


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## c.o.d51 (Nov 7, 2005)

cummings said:


> thats crazy. how much travel. sorry if you mentioned it, i didnt read all the words..


8" via a 9.5X3 shock.

65*HA, 14" bb height and stupid low standover height.


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## shredder111 (Jul 8, 2005)

That is a sick project, makes me wanna go build something. It's teh sickness seriously, you've got me interested. I love these DIY projects, good luck to you mate!!!!!!!!!!


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## geoffss (Mar 23, 2004)

c.o.d51 said:


> And how it sits as of right now:
> I'll keep this thread updated!


Are the bolts loose, or is the frame horribly out of alignment???


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## snow-man (Aug 19, 2004)

DUDE that's so mad scientist!
Looks killer, 
Rock on!:thumbsup:


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## jimage (Dec 22, 2006)

sick,powder it red and put dee max in it sweet


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## c.o.d51 (Nov 7, 2005)

geoffss said:


> Are the bolts loose, or is the frame horribly out of alignment???


For some odd reason, part of the front triangle slipped in the jig. What matters IS in alignment though, so there's no need to worry. And, the bolts aren't tight. The rear triangle on the other hand, is damn near perfect.The wheel is off because he's using the wrong axle.

Dee Max? I think not. Clapped out 823's? Yup.


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## tibug (Dec 5, 2006)

Holy crap!!! You actually did your own geo and everything. I've toyed with frame design and just use Cad with Santa Cruz single pivot specs or, if I feel ambitious, I'll try their v10 design (takes too long). I think you should design your own headbadge and powdercoat that frame forest green and put deemax like jimage said so it can be a FS tractor!!! Like if you're using a PC, the start button color. 

649 days, 7 hours, 4 minutes,
Tim


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## R1D3R (Jun 4, 2005)

Looking good! Whats the weight?


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## Godzilla (Mar 31, 2005)

That is super cool, is this a one time deal or does your friend have plans for it?


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## Sombrio69 (Apr 21, 2005)

damn. thast all i can say right now. the front triangle looks almost as if u fliped around a BMX frame. great work.


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## jimage (Dec 22, 2006)

what program did you use??


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## xKREDx (Aug 8, 2006)

Man that is sick!


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## c.o.d51 (Nov 7, 2005)

Godzilla said:


> That is super cool, is this a one time deal or does your friend have plans for it?


He's got some plans, and they're fairly large for the future.

It won't have Dee Max wheels.

Program was Solidworks. Good, easy program that just plain works.


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## ll 3nZo ll (Feb 15, 2007)

Wow that truly is AMAZING!! Props to you and your friend for doing such an awesome build.


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## Andrew2007 (Mar 11, 2007)

That's AWESOME :thumbsup:


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## austinb89 (Nov 6, 2004)

just amazing. i really waan build my own frame


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## BikeSATORI (Mar 20, 2004)

trickness with the sickness. props to your homey, he's goin' places.


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## SHIVER ME TIMBERS (Jan 12, 2004)

very sweet....nice job


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## lj17 (Feb 1, 2007)

What brand of seat clamp is that? I would like to get one of those...

BTW, awesome job :thumbsup:


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## balfabiker22 (Feb 26, 2006)

Sweet, STEAL IS REAL...how much is the wheight? of the frame.:thumbsup: 

Great job btw.


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## Ithnu (Feb 16, 2007)

As an engineer I have to say, that pretty F'n cool. I saw you used Solidworks, did you run any FEA? Or just some hand calcs? Either way, nicely done.

I used to ride with guys who built their own head sets and brake mounts, but nothing like that.


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## todd_freeride (Aug 9, 2005)

thats so totally awesome. I wish I had skills to do that kind of stuff.


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## kuksul08 (Oct 8, 2006)

Wow, that's awesome. Chromoly steel is very strong and the whole design looks nice overall. 

I'm a mechanical engineer in training. I learned how to weld a few months ago and use a lathe just a few days ago, so this is awesome! Oh yea, I'm learning solidworks now too, awesome!

If I had all those tools, , looks like fun


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## VooDoo13 (Jan 29, 2005)

In 1948 everyone thought Preston Tucker was either crazy or a con man yet many of his innovations have been used in modern automobiles for the last 50+ years. This could be the beginning of something. Way to go fellas :thumbsup:


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## pvflyer (Dec 7, 2004)

Good work, I wish i could do it! Congrats on your Bike i don't know if that is your first time trying doing it a bike from scratch, but it looks pretty darn nice.


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## c.o.d51 (Nov 7, 2005)

Ithnu said:


> As an engineer I have to say, that pretty F'n cool. I saw you used Solidworks, did you run any FEA? Or just some hand calcs? Either way, nicely done.
> 
> I used to ride with guys who built their own head sets and brake mounts, but nothing like that.


Yep, he ran FEA.










This first frame, which is completely overbuilt, weighs in around 12.5-13lbs, with shock and mounting hardware. Next one, which will be aluminum, will weigh in hopefully in the 9lb range. The next version is basically going to make this one look like crap, and hopefully ride like that too. It's going to be sick.


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## Havefaith (May 8, 2006)

Nice work guys! Just as a tip, from one engineer to another, dont put all your trust into FEA. That analysis looks flawed in the use of your constraints. The bearing bores should be cylindrical supports (or bearing loads for that matter) rather than constrained in all directions. I know cosmos is limited, but you should be able to do something about that. Just a tip for the future.

Nonetheless, everything looks solid and reliable! Good luck for everything to come. I wouldnt mind ripping that thing, thats for sure....


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## ehansen007 (Sep 8, 2006)

This is the coolest damn thread I've ever seen.


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## dirtydownhill (Aug 11, 2006)

That is simply amazing. The design looks like it would perform really well. So inspirational, I think weve all dreamed about designing and building a frame but you actually did it. Good on ya' Definitely keep us posted and get that linkage patented really soon.


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## AltitudeDude (Jun 22, 2005)

Really nice work. Are you majoring in mechanical engineering?


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## AKRida (Feb 26, 2004)

that bike looks pimp dude! good job.. i'd ride it


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## Fox787 (Jun 2, 2005)

isg mounts?


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## xR1DeRx (Jan 21, 2007)

Thats awesome....looking forward to seeing this beaut compete!!!


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## c.o.d51 (Nov 7, 2005)

Fox787 said:


> isg mounts?


Weren't mounted yet because he needs to replace the bottom bracket shell.

He will be majoring in mechanical engineering. Should be sweet when it's done!


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## rep_1969 (Mar 25, 2004)

WOW! That's pretty cool, good job.


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## CharacterZero (May 19, 2004)

Incredible work!~


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## taw69 (Apr 15, 2007)

Hi'
amazing project...cant wait to see the final product!
is it done yet??? can we get some more info on how its going?
anyway - I realy understand how much work it is as i'm also studying CNC and solidworks right now, and would love to see more of the project!
Thumbs up!
Tim


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## ljsmith93 (May 16, 2007)

so awesome:thumbsup:


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## mrpercussive (Apr 4, 2006)

yea... i forgot about this thread too... updates???


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## kenbentit (Jan 2, 2003)

How's the shock clearance working out? The animated vid. seemed to show the reservoir hitting or getting real close to the vertical section at full compression.


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## SHIVER ME TIMBERS (Jan 12, 2004)

very good work


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## hiredgun (Jun 6, 2007)

I didn't join MTBR until this June and first saw this thread today so i'm behind the times to add my comments; but I will anyways.

First off cool project :thumbsup: .

If I had a less demanding professional life I would be doing similar projects.

Secondly; the picture of the head tube in the lathe (below) scared me and if that is how you mounted the head tube to machine it then you placed more stress on the chuck than you should and that is probably why it failed and exploding lathe parts can cause considerable damage.

I am an amatuer machinist and have learned that the tooling is everything when it come to making good parts. the cool thing is that you can often make what you need and therfor it doesn't have to be a big financial drain.

If you don't allready know this do anything you can to mount your work betwen centers and do not support work soley in the chuck unless you are working very close to the chuck and have almost nothing protuding past the chuck. work done between centers will be more precise as there will be less tool delfection and it is safer.

For mounting hollow parts between centers I use a live center with interchangable bits to fit different shape parts.

The pic below is from MSCs catalog of an economical live center kit.


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## derfernerf (Jun 25, 2006)

thats CRAZY!!!! mad props on DIY frame.....i dont like the seat tube angle, but hey, im not making it so i guess i cant be picky....its very nice tho, i like the shock location ALOT


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## =ChrisB= (Aug 8, 2006)

****ing... ****ing.... **** that is some realllllly cool stuff!


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## unclegreaser (Jul 21, 2006)

i just saw this thread too....

had the same concern as hiredgun.

also in your design that rear triangle is gonna wag like a happy puppy tail when subjected to side load forces(turns with bumps and heavy pedaling, maybe braking forces too).

if it doesn't tear the bearings out it may cause premature bearing failure.

i would really like to hear from you after it gets some rough testing. if it holds up i have a dual shock frame idea thats like that but different cause everything is much lower on the frame.


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## 317000 (Mar 2, 2007)

wanna be a bro and send me that solidworks complete frame file?


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## Gonz (Feb 8, 2004)

*Nice Job*

Mechanical Engineer here ... 20 years in Aerospace, mechanical flight controls. Seattle WA - we got some way sick trails out here, plus Whistler is just up the road.

You want a job ? send me a PM.


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## renderedtoast (Dec 6, 2006)

Its cool to see the actual mechanics that go into bike frame building. Most people (myself included) just throw a leg over them and ride. You never think about what it takes to get it all to function. Thanks for the education lesson.


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## Jake0521 (Jun 15, 2007)

This thread is awesome, I wish I had the know how to make my own frame any updated pics?


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## coghi (Jan 5, 2007)

what kind of engeniring is needed, for designing a bike? ive been always curious. 
cool job, awesome bike.


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## tacubaya (Jan 27, 2006)

Mechanical engineering


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## thatdownhillkid (Mar 11, 2007)

i wanna build my own frame
even if its just like copying an already established frame design i still wanna build my own


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## William42 (Oct 29, 2006)

the guys over at ride monkey have this same thread, just with the outcome.

check it out

http://www.ridemonkey.com/forums/showthread.php?t=175469&highlight=obsession


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## derfernerf (Jun 25, 2006)

hes not going to finish it....atleast not for awhile :bluefrown: :sad: :sad: :sad: :sad:


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## monkeyfist23 (Dec 7, 2005)

There is a guy who has been riding at Diablo the last few weekends with a home built square tubing 11" rear travel steel frame. Its awesome, you can't miss it with the bare metal and square tubing. I'm not sure why he doesn't post here... Mad props to those who can do this kind of work. Truly an art form!!!


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## Wizard4620383 (May 12, 2007)

wow i didnt saw that post .. but good work men ! seem to be a good geo .. can you tell me whats the Head Angle ?


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## DickemDown (Jun 23, 2004)

dope.


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## toyota200x (Sep 9, 2005)

That bike looks amazing. :thumbsup:


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## dustyrider (Feb 19, 2004)

just checked the link from ride monkey the bike building appears to have stopped....


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