# Fooly's Major Glory



## dacosta (Jul 23, 2010)

After months of procrastination I finally have a working design. I would like to present my work in progress:

Fooly's Major Glory - 650b Titanium Soft Tail, Rohloff/Gates belt drive.


If I can get my butt in gear, I should have this frame completed by end of January 2013. And parted up by end of February or early March, just in time for the Sol-Cal Kenda Cup.

Over the next few weeks I hope to document some of the progress on the project. I hope you enjoy it.

Dan "Fooly" Acosta


Edit: added some pictures of the parts I've been collecting.
Edit: added some pictures of some of the custom parts I've been making
Edit: added some pictures of more bits that came in. Added the Chain Stay and Seat Stay tube from the tube bender.


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## dacosta (Jul 23, 2010)

Edit: Recycling old artwork for new frame.
Edit: Added linkage design


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## dacosta (Jul 23, 2010)

*Graphics are done*

The graphics are done!

I hand anodized the head tube logo, the name of the bike and rear triangle. Not sure if you can tell from the picture but the rear triangle has a gold tint to it. The head tube logo is the simplified version of my disk wheel.

Need to finish collecting parts. Had a small delay with some unexpected bills but should have the bike up and running by the end of November.

Enjoy

Fooly


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## OSKIN100 (Jan 2, 2008)

Reserved for congratulations! 

Really though it is about time. Good luck and have fun.


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## G-reg (Jan 12, 2004)

It's my understanding Rohloff are super picky about properly stiff chainstays when using a belt. Are you confident that your design won't allow tension to change too much?


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## StanleyJ (Dec 11, 2010)

G-reg said:


> It's my understanding Rohloff are super picky about properly stiff chainstays when using a belt. Are you confident that your design won't allow tension to change too much?


I suppose it does "pivot" around the bottom bracket... and the new/current CenterTrack belts should be more tolerant of changes in tension? *shrugs*


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## G-reg (Jan 12, 2004)

Ah! That's why I asked. It looks like it wouldn't pivot....it would bend.


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## dacosta (Jul 23, 2010)

Since it is a soft tail, I am not getting a lot of rear wheel travel. From the neutral position (mid travel) the chain is at its longest. To the fully extended position I am calculating the chain line to shrink by about 0.040 inches. And to the fully compressed position the chain line will shrink about 0.065 inches. My test bike with a more traditional rigid frame design this is just a few turns of the adjusting screw. My tests seems to show this will work just fine. May not be the best for the belt, but I confident that this will work better in the long run than the traditional chain.


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## Blaster1200 (Feb 20, 2004)

Reserved for comments.


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## Walt (Jan 23, 2004)

*Reserved*

Reserved for flame wars, posturing, and whining.



Seriously, I think you are going to have major problems with a belt on a softail. Even very small amounts of chain growth are going to be murder with those tension requirements. But you can always just throw a chain on it, so it's not the end of the world if it doesn't work out.

Care to share the geometry numbers?

-W


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## shiggy (Dec 19, 1998)

dacosta said:


> Since it is a soft tail, I am not getting a lot of rear wheel travel. From the neutral position (mid travel) the chain is at its longest. To the fully extended position I am calculating the chain line to shrink by about 0.040 inches. And to the fully compressed position the chain line will shrink about 0.065 inches. My test bike with a more traditional rigid frame design this is just a few turns of the adjusting screw. My tests seems to show this will work just fine. May not be the best for the belt, but I confident that this will work better in the long run than the traditional chain.


You need to learn the difference between chain line and chain growth.

It is not just chain growth than can cause issues with belt drive. Some rigid frames have problems because of lateral and/or torsional flex.


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## dacosta (Jul 23, 2010)

69ºHT, 73ºST, Eff TT 21.25", ST C/T 16.5"


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## estutjaweh (Jan 3, 2008)

What rear belt sprocket are you going to use? Rohloff won't sell theirs unless the frame is certified by Gates...and even then they won't sell the adapter, you have to ship you hub to them to get it fitted! 
As far I understand hub warranty is also void if you use anyone elses sprockets because these components incorporate the hub seal surface bit. How are you getting around all these hurdles?


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## dacosta (Jul 23, 2010)

"You can not make anything full proof, as the world will simply make a better fool."
(unknown)

I reserve the right to be that fool.

Rohloff hubs and Gate's belt drive are both available from QBP and BTI. All you need is an understanding bike shop that is willing to order the parts for you. Since I am building the frame all manufactures warranties are voided, including Shimano, Sram, Rockshox ect. As a result I take on the responsibility, and the reliability of the design rest only on my shoulders. If it does fail I have no one to blame but myself.

Since I have no intention of starting a buisness, nor do I plan on building this frame for anyone else. I can design this frame for the singular purpose for myself. I choose to build a bike that can not or should not be built, as an intellectual and creative challenge. 

The design was done in Solidwork, the analysis was done with Cosmos. I built a test bike with the Gates Belt and Rohloff hub. I've tested an intentional miss alignment and incorrect tension on the belt. With all of this I am confident that this will work.

Fooly


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## estutjaweh (Jan 3, 2008)

So where do you get the rear sprocket adapter thing from then? QBP have the gates and rohloff stuff yes, but these won't fit together without some adapter that only rohloff themselves make...and won't sell separately (GGGrrr)...god knows I've tried to get one!


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## TrailMaker (Sep 16, 2007)

estutjaweh said:


> So where do you get the rear sprocket adapter thing from then? QBP have the gates and rohloff stuff yes, but these won't fit together without some adapter that only rohloff themselves make...and won't sell separately (GGGrrr)...god knows I've tried to get one!


If a part can be made by one entity - Rohloff, say - it can be made by another. To paraphrase, overcome and adapt!


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## febikes (Jan 28, 2011)

dacosta said:


> Fooly's Major Glory - 650b Titanium Soft Tail, Rohloff/Gates belt drive.


Why belt drive?

It seems to me that it will be problematic because even on hardtails belts seem to be fairly problematic. For a suspended bike the movement in the rear end could cause issues.

What is your motivation for running belt?


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## dacosta (Jul 23, 2010)

Have you tried Cycle Monkey? It seems to me that he is the guy for Rohloff service in the USA and he also sells parts for the Gates belt drive. If you are still having problems you may just have to buy a new hub with the cog already attached. ($$ouch)

I've been riding mountain bikes off and on for the last 20 years. I've been riding the same mountain bike for the last 12 years. I'm getting really tired of the constant chain maintenance. I want this next bike to last another 12 years with out all that chain maintenance and all that shifting issues that go along with the chain. My test bike is almost a year old now, and is now my road bike and daily commuter. Sure it was a pain to set up but I now I just pump up the tires and roll out.

If the belt doesn't work I can always swap out the belt back to a chain. And I can always swap out of the Rohloff for a more traditional chain-gear system. The point is to try the belt and see if I can get it to work for me. This project is all about the journey and not so much about the destination, although the destination is also pretty cool too.

Fooly

PS. Mark I really like your web site. If I wasn't so lazy I would be following in your foot steps.

Fooly


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## febikes (Jan 28, 2011)

dacosta said:


> I'm getting really tired of the constant chain maintenance. I want this next bike to last another 12 years with out all that chain maintenance and all that shifting issues that go along with the chain.


I feel you on the chain maintenance headaches but the past couple of weeks I have been pretty happy with my monster chain. I am running a motorcycle chain on a single speed bike but there is no reason it would not work for belt drive.

My chain is the one on the left 









It runs on a special custom chain ring and cog that we made from motorcycle sprockets.









I am hoping it will give me improved chain life so if your belt does not work and you want an extra tough chain think outside the box.


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## dacosta (Jul 23, 2010)

Again Kudos to you Mark Farnsworth, very nice.


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## Francis Buxton (Apr 2, 2004)

Really? Chain maintenance on a singlespeed? Lube it every two weeks and ride it until it stretches, and replace it with another $35 chain. Seems easier than all the intricacies of belt drive to me.


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## Yogii (Jun 5, 2008)

How much does the motorcycle chain weight? Must be a boat anchor.


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## Walt (Jan 23, 2004)

*Chain wear, really?*

I have SS drivetrains with plain-jane PC951 chains on them that have lasted years and years, thousands upon thousands of miles, with nothing but the occasional squirt of lube. I don't understand how people have these crazy chain wear problems...motorcycle chain, really?

Occasionally I have a friend come to me with chain problems on their SS and it's inevitably an issue of running a 3/32" cog with a 1/8" track/BMX chain (which they usually bought because it was bigger/burlier looking). If you avoid that, you should be golden for a LONG time.

-Walt



Francis Buxton said:


> Really? Chain maintenance on a singlespeed? Lube it every two weeks and ride it until it stretches, and replace it with another $35 chain. Seems easier than all the intricacies of belt drive to me.


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## febikes (Jan 28, 2011)

Walt said:


> I have SS drivetrains with plain-jane PC951 chains on them that have lasted years and years, *thousands upon thousands* of miles, with nothing but the occasional squirt of lube. I don't understand how people have these crazy chain wear problems...motorcycle chain, really?


A chain will last 10,000 years or more if it is not used but I call BS on the millions of miles claim.










The chain above was less then 2k miles using good quality 3/32nd drivetrain parts.

In off road conditions a chain will last at most 2k miles before bad stuff starts happening. With adverse conditions like mud and rain chain life is reduced.

The moto chain is crazy overkill but it is going to last a while. I tend to do around 200 miles a week on my single speed. Most of my riding is off road. Some weeks I do more while other weeks I do less. Chain stretch usually means an adjustment every week or two and end of life after a month or two. The idea with the moto chain was just to have fun and do something a little over the top but it sure rides nice and is perfect for my training bike where I don't care about weight.

p.s. sorry for the thread hijack. It will be fun to see Fooly Major Glory come to life, I think belt drive is interesting but still not so sure it will work on a full suspension bike.

-Mark


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## Walt (Jan 23, 2004)

*Really?*

I don't think "thousands upon thousands" is usually understood as "millions". That would be "thousands OF thousands".

Well, YMMV, I guess. I have ridden a lot of singlespeeds a lot of miles over the years, though certainly nothing like your ~30 miles offroad per day average (wow!). If I had to estimate, I'd say the average chain lasts me 4-5k miles (for me, a couple of seasons). At a retail cost of ~$25/chain for a 951, that's peanuts.

But if you're trashing chains every month, I can see why you'd go for something beefier. That is the most riding (you've gotta be doing 30+ hours a week!) I've ever heard of anyone doing on a regular basis who isn't a full-time pro!

-Walt



febikes said:


> A chain will last 10,000 years or more if it is not used but I call BS on the millions of miles claim.
> 
> 
> 
> ...


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## febikes (Jan 28, 2011)

Ya, I got more the my average amount of miles this year by a long shot so chain wear was also more then expected. I do ride a lot though but mostly junk miles with 12 miles to work in the morning and then another 12 miles back home most days so it really just replaces time that would be spent in the car. Bikes are fun so weekends and evenings are sometimes more miles although I ride less when I am building a frame on the weekend.


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## NEPMTBA (Apr 7, 2007)

Chains?...
...let me ride it!:eekster:



NEPMTBA said:


> Works like Stink...
> ...now if I can just figure out how Stink works


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## zipzit (Aug 3, 2005)

I'm curious about the combo lathe mill. Is that a Shopmaster ? Cnc Milling Machine, Metal Lathe Mill Drill, 3 In 1 Machine is that a CNC version?


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## kosayno (Sep 7, 2006)

Some have mentioned about chain growth. I fail to see how it would have any chain growth if it's pivoting at the bottom bracket. I think the adjustable dropout is unnecessary since your chainstay will shorten when it flexes during compression. I would use a regular dropout along with a chain and tensioner.


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## dacosta (Jul 23, 2010)

Zipzit:
A friend of mine has a hobby shop in his garage, I am simply borrowing some time in it. Here is what he has to say about it.

"The basic info is the larger machine is a 2008'ish Shopmaster with DRO (no CNC), acme or non-ball screws (that was a mistake...really should have gotten ball-screws) and constant speed motors (i.e. not Variable Frequency Drive (VFD) so to change tool speed you need to change belts).

The smaller mill and lathe are Sherline CNC. Around 2006'ish. This system has been abused but with replacements parts (that where a reasonable cost) it effectively operates as new. The abuse was from learning and machining parts too fast or too heavy. Not production type work.

So basically the big machine is for hitting big stuff hard or rough cutting items for the little machine. And of course the paradigm you need a second machine to work on the first machine does apply at times"

kosayno:
The main point of this design is to get away from the chain. A chain tensioner (or belt tensioner) would not be ideal in this application due to the nature of the belt limitations. I guess I could design the bike with the proper chain stay length.... but alas I'm not that good.....yet.....


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## Drew Diller (Jan 4, 2010)

dacosta said:


> I guess I could design the bike with the proper chain stay length...


I was told that trying a magic gear setup wouldn't be great as "even a quarter turn" on a Paragon style dropout positioning screw creates a measurable difference in tension.


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## febikes (Jan 28, 2011)

A magic gear setup is never a good idea. After a couple hundred miles you would need to replace the chain. Sure it can be done but generally you will be riding a chain that is too loose most of the time or you will be replacing your chains very often to maintain the magic length.


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## Drew Diller (Jan 4, 2010)

Kinda what I figured... I had an White Brothers Eccentric Eno hub on my last MTB, mated "dingle" speed style to a Hammerschmidt crank. I had to adjust the hub pretty frequently. In one case it was hub slip, but over the longer haul it was chain wear (also chain *stretch*, literally, on a half link chain, the plates would bend slightly straight).


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## dacosta (Jul 23, 2010)

Here is a 29er version that I was originally working on but abandoned.


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## dacosta (Jul 23, 2010)

Here are some updates on the bike project. Updated the design for a different fork than what was originally selected, Also corrected some minor design flaws.

Other pics:
The intermediate linkage is done, still need to fit and finish.
Upper pivot sleeve.
And lower pivot spacers.

PS. Bah can't edit old posts


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## dacosta (Jul 23, 2010)

Another update.

Hub and parts for the rear wheel came in.

Also finished some detail work on the linkage. Installed the bearing and bolts for show.


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## thunderzy (Jul 23, 2010)

Phenomenal


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## MnMDan (Nov 14, 2011)

Can't wait to se that bad boy in action trying to keep up with you.


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## Rantz (Dec 20, 2012)

I like that motorcycle chain idea.


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## dacosta (Jul 23, 2010)

Disaster!

This week was the week planed to do the actual building of this frame. All the parts and all my tools that I needed for this project was packed away and sent on ahead of me, to the shop upon I had previously arranged to build my frame. Also I had sent my luggage with all my clothes I would need for a week. Upon my arrival, only my bike had arrived on time. Most of my parts were delayed. I had tracked my packages most were scheduled to arrive on Monday, with the rest strangling behind. But come Tuesday, the packages were lost and delivery could not be determined. At this point my trip is a bust and my project is lost. I have spent the remainder of Tuesday traveling back home. I am now expecting a fight with UPS for reimbursement of all that I have spent on this project so far. 

Fooly


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## Walt (Jan 23, 2004)

You might look into a local metalworking collective - many cities have them. You usually pay a small membership fee and then can use the tools. Where were you planning to do your building?

Sorry to hear, but don't give up on us!

-Walt


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## pvd (Jan 4, 2006)

That sucks. Sorry bro.


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## Yogii (Jun 5, 2008)

> You can not make anything full proof, as the world will simply make a better fool.


TAG, your it......


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## GMF (Jan 10, 2004)

I really dig the simplicity of your design, but having had a soft tail with a nearly identical chainstay setup, i'll caution you about going down that path. Chain forces will naturally want to compress the suspension and you'll get a sort of inch-worm effect. Now, my frame was built like 10 years ago before all the fancy platform valving, so that may address the problem, but just know that is an inherent issue with with this kind of design.
Having said that, i really dig it and hope it works out well for you!


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## dacosta (Jul 23, 2010)

*Back at it*









Sorry for the long delay, UPS did not corporate.

Jim Kish of Kish Fabrication, teaches the UBI titanium frame building class. I figured that if anyone would let me use his shop it would be the guy who taught me. Unfortunately Kish's shop is in North Carolina and I am from Southern California. Hence the shipping parts by UPS and all that hassle that went along with that.

By chance I recently found retired frame builder Josh Ogle, he happens to still have all of his frame building equipment. He also letting me rent time in his shop to build my bike. And luckily he recently moved back to Southern California.

Day one was spent on practice, practice and more practice. His equipment is a little old and has some issues that I need to learn to work around. Either that or I am rusty around machine equipment. (I mean no offense Josh if you are reading this! Really your equipment is great I am just glad that you let me into your shop!)

Day two was spent on more practice, but I was able to miter the tubes and fit them in the frame jig. (see the attached picture) I still need to fine tune the fit, tack weld, and start welding, but that is on the plan for day 3.

Day three will be in two weeks. Hopefully I will have a lot more pictures to show off.


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## MnMDan (Nov 14, 2011)

Glad to see you're back in production.


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## dacosta (Jul 23, 2010)

*Day 3 & 4*

opps added post in the wrong spot... how did I do that?

ugh...


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## dacosta (Jul 23, 2010)

*Day 3 & 4*

Back at it after another long delay. Day 3 was spent first with some practice welding, especially after the long delay. The afternoon was spent welded the seat tube collar onto the seat tube. Then welded the seat tube on to the bottom bracket shell. Then Drill out the vent holes and water bottle holes in the seat tube. Also I was able to weld the tips on to the seat stays.

Day 4 was spent prepping the top tube for the suspension bits. Then welding the suspension bits to the top tube. Also I drilled out the vent holes in the head tube.

Back at it again next week.

Enjoy

Fooly


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## dacosta (Jul 23, 2010)

*Day 5, Starting to look like a bike*

Had to re-cut the down tube as I had screwed up the first one. Got all the tube set up in the frame jig, tacked it up and welded up the front triangle. Its starting to look like a bike!


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## dacosta (Jul 23, 2010)

*Fit and finish the linkage and shox*

Spent some time fitting and finishing the linkage and shox mounting.


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## dacosta (Jul 23, 2010)

*Day 6*

Some more work this week. Got the chain stays all jigged up, tacked up and welded to the frame. Also started with some of the smaller bit, like the water bottle braze-ons.

Enjoy

Fooly


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## Walt (Jan 23, 2004)

Looking good! How did you ovalize/flatten the stays? Are you worried about breaking them at the flat/round transition area? 

I want to see this thing assembled and ridden before the 1 year anniversary of the thread!

-Walt


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## golden boy (Oct 29, 2008)

What's the story on the linkage? Was it cast?


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## dacosta (Jul 23, 2010)

Thanks Walt

I am shooting for that date, but this is a labor of love for me and I want to savor each step of the way. Plus who knows what I might screw up next…

As for the chain stays, there is about a one and a half inch gradual transition between the full round and full oval’ized section of the tube. I am not worried at this transition, if it does fails it will be a fatigue failure just after the weld at the bottom bracket. I tried to limit the stresses at this point to the fatigue limit of titanium (about ½ the yield strength). But fatigue calculations is never certain and just an approximation. I tried to simulate what I can remember from looking at a Moots frame, and tried to keep similar stress on this design but increase the travel with the shape of the chain stay. I should get about 1 ½ inches of travel from this design.

As for the design… I shot for the moon and barely hit it. I started with ¾” x .035” thick Grade 9 annealed. (I think most frame builders stick with CWSR (cold worked stress relieved), but you will see why I choose annealed in a minuet.) I started with enough tubing to make 12 pieces, 6 seat stays and 6 chain stays. For simplicity the s-bends were identical for the seat stays and chain stays, right and left. The chain stays would just have the additional feature of the oval’ized ends. I took the tubes to a local professional tube bender. My yield was terrible, from my original twelve pieces I only got two chain stays and two seat stays. Most of the chain stays split at the edges trying to create the oval section. I was too aggressive in the design for the tubes to deform to the shape that I wanted.

Since annealed is not a strong as CWSR, and fatigue life is dependant on yield strength. Although annealed is formable while CWSR is not. It was foreseen that I would have to heat treat the chain and seat stays. There is some discussion about whether or not Grade 9 annealed can be heat treated. Through my own research, and my memory of my old metallurgy class in collage (I’m a mechanical engineer by training). I believe that Grade 9 can be heat treated, and I was able to find information on a process called STA (solution treated and aged). The process can bring up the yield strength of titanium close too CWSR, though not as strong as CWSR. After calling around for some time I found a heat treatment shop who would do the process that I described and in a manner fitting for titanium. Since destructive testing is outside my budget, and no parts to test with. I have no idea the resulting yield strength after heat treatment. Therefore this is somewhat a leap of faith that the strength is adequate. 

Sorry for the long response, but this step was a challenge. I am happy that I can share this.

Fooly


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## dacosta (Jul 23, 2010)

Goldenboy

The linkage is DMLS (direct metal laser sintering), 6/4 titanium and its hollow!

I was originally looking at doing an investment casting. However for just one part no one wanted to switch over to the high quality metal, and to make the bearing holes required secondary machining. Next I considered having the part CNC'ed, the cost was lower than having an investment cast plus the secondary machining.

I was working with a local prototype shop who specialize in small run stuff. But the salesman kept pushing to run this part on his new 3d printer. I had made parts in SLA (stereolathagrophy) and SLS (selective laser sintering) before for my regular job. But I absolute didn't want this part in plastic, no matter how good the process has improved since my last few time I had made some parts.

But this got me thinking, has SLA/SLS improved enough to start making parts in metal?
After doing some research, indeed they do! And in Titanium! I was sold, I redesigned the linkage to take full advantage of the DMLS process. And there it is!

Fooly


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## golden boy (Oct 29, 2008)

Thanks, Fooly. Every custom bike frame is a labor of love, but you have taken it to a whole new level. These new fab technologies are so cool, giving us the ability to have one-off parts made without expensive tooling. Speaking of expense, I am curious what this part cost you. No problem if you don't want to say in this thread. You could shoot me a PM if you like. So was this done by the 'local prototype shop' that you mentioned? Or did you have to look further afield to have this done? My bachelor's degree is in industrial design and I find this stuff fascinating. Thanks again, and good luck!


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## dacosta (Jul 23, 2010)

*Day 6.5 and Day 7 - Its almost done!*

Day 6.5 was spent at my friends shop doing some prep work, mitering both ends of both seat stays.

Day 7 is spent tacking the seat stays to the frame and welding them in place. Also checked alignment, and more braze-ons.

All that is left to do is finish the Braze-on bits, and ream out the seat tube, head tube and bottom bracket. After that, then the graphics, and parts.

Enjoy

Fooly


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## dacosta (Jul 23, 2010)

*Day 8 - Construction Complete*

Finished welding on all the braze-ons. Mounted the shox and welded on the "Brain" tab. Reamed out the seat tube, heat tube. Chased and faced the bottom bracket.

Next up is the graphics, then parts.

Enjoy

Fooly


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## Walt (Jan 23, 2004)

The old-school brain shock with integrated tab takes this over the TOP. Awesome!

Let us know how it rides!

-Walt


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## dacosta (Jul 23, 2010)

*Small update*

The frame is back from the Etcher. Stencils and spoke cover back from the printer. Also a few parts came in.

Enjoy

Fooly


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## dacosta (Jul 23, 2010)

*Graphics are done*

The graphics are done!

I hand anodized the head tube logo, the name of the bike and rear triangle. Not sure if you can tell from the picture but the rear triangle has a gold tint to it. The head tube logo is the simplified version of my disk wheel.

Need to finish collecting parts. Had a small delay with some unexpected bills but should have the bike up and running by the end of November.

Enjoy

Fooly


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## dacosta (Jul 23, 2010)

*Parts are in - Fit and finish (fixing mistakes)*

Parts are in, now just need to put it all together.... and finding all my mistakes and fixing things to make it work.

Fooly


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## kosayno (Sep 7, 2006)

Carbon belt looks slack and the nose of the saddle is really pointed downwards.


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## whydomylegshurt? (Jul 28, 2004)

kosayno said:


> Carbon belt looks slack and the nose of the saddle is really pointed downwards.


The guy just designed and built a full suspension-single speed-titanium-belt drive bike and all you can comment on is the belt tension and saddle position? My gut feeling is the picture of the bike is still being built, not the finished product. It seems likely that if someone knows enough to make it as far down the road as fooly has they can probably take care of the saddle position.


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## afwalker (Apr 26, 2012)

Did you have to notch room for the chainring with your mill?
How'd you fill the defect, weld or braze something in there?
Why not dimple?
Your hold down clamps for the chainstays look like they would hold it pretty good.
cheers
andy walker


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## dacosta (Jul 23, 2010)

Its not quite finished yet. While assembling the bike I discovered that I have to much wheel clearance and not enough chain ring clearance. My CAD model suggested that this would have worked if I had made the chain stays perfect. But I was sloppy with my inexperience. 

Since the frame is titanium, I am limited on what I can do at this point. Perhaps I could have dimpled the chain stay if I had more fore site in the beginning. But at this point I can not not heat the frame to dimple without contamination. Therefore I machined out a slot and this coming weekend I will weld in a new piece to fill the hole.

More pictures to come.

Fooly


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## ohpossum (Dec 19, 2003)

Ok, I'll bite..

No split in the CS or SS for the belt? I admire your "all or nothing" commitment


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## dacosta (Jul 23, 2010)

There is no "break bridge," removal of the belt it thought the suspension linkage. I'm just being lazy and not removing the belt while I make the slot in the chain stay. 

Fooly


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## whydomylegshurt? (Jul 28, 2004)

ohpossum said:


> Ok, I'll bite..
> 
> No split in the CS or SS for the belt? I admire your "all or nothing" commitment


Looks like you would just unbolt the suspension link to slip on the belt.

Edit: Fooly beat me to it.


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## afwalker (Apr 26, 2012)

Thanks for the reply, been there done that, but not in ti.
Makes sense to me, it's gonna be great since ti will weld up pretty
Bikecad's been a learning curve for me, but if you put all the right numbers in it models up the stays pretty good. What cad are you using?
BTW, super amazing ti sintering over the top stuff! Makes all of us jealous!
cheers
andy walker
Flickr: afwalker's Photostream


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## dacosta (Jul 23, 2010)

Thanks Andy

I'm running SolidWorks 2005. Its a little old by now, but I am still proficient at it. Plus it comes with Cosmos. Cosmos is a simple stress analysis solver that I used to calculate the stresses on the bike before I began building this project. Which is a good thing as for this repair I could quickly see if I am not introducing any stress concentrations above the allowable limit.

Also with SolidWorks there is quite a library of parts that people have drawn up over the years (Free 3D CAD Library and Collaboration Tools for Engineers - GrabCAD). I was able to download the Rohloff hub, 650b wheel and a few other small items that I used to help with the design.


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## kosayno (Sep 7, 2006)

whydomylegshurt? said:


> The guy just designed and built a full suspension-single speed-titanium-belt drive bike and all you can comment on is the belt tension and saddle position? My gut feeling is the picture of the bike is still being built, not the finished product. It seems likely that if someone knows enough to make it as far down the road as fooly has they can probably take care of the saddle position.


It's a beautiful bike. I wasn't criticizing. Just stating my observation and trying to make a joke. With the amount of detail and hard work he's put into this project, it's obvious he's more than capable of tensioning the belt properly (yet the belt is slack, hence the lame attempt at humor) and the saddle is personal taste if that's indeed how he wants it to be positioned. Next time I will use a smile-e. Carry on.


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## dacosta (Jul 23, 2010)

*Bawah ha ha.....*

Its done. It ride like a dream come true! My face is cramping I am smiling so much!

No pedal bob, no inch worming, the Brain effectively keeps the rear end like a hard tail. Once I start riding over the rough the brain unlocks and the suspension opens up. The front end is so much more stable than my old 26er. The 650b wheels just floats over the rock gardens. Everything I wanted in the bike is delivered!

Fooly

PS. I should have taken a picture while on the dirt, but I was having such a good time I didn't want to stop.


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## TrailMaker (Sep 16, 2007)

Hey;

It's so cool when a plan comes together, and yours took patience for sure. Glad it is all you wanted it to be. Very rewarding!


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## melster (Sep 11, 2009)

In case you guys don't know Dan very well, this guy is a monster rider. He routinely rides entire 40 mile rides beating every single one of my PRs in every segment of said 40 miles on Strava. And it's not even close. He's fast uphill, downhill and sideways too, I'm sure. ;-) 

I'm scurred to see him riding this new bike now.

I know it was a joke, but with all those miles under Dan's wheels, if anyone knows how to fit his bike, it would be him. ;-)


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## dacosta (Jul 23, 2010)

Thanks Mel!


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## MnMDan (Nov 14, 2011)

Damn nice build. Its going to be hard keeping up with you now that your rig is going to keep you fast no matter what the terrain might throw at you.


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## builtboosted (Dec 16, 2013)

does anyone notice that the rear triangle at the bottom where it mounts to the crank bearing housing is solid? how is the rear going to travel up and down if it doesnt have a second pivot point?


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## melster (Sep 11, 2009)

It's a softtail. Even though it is solid, the metal will flex enough for a limited amount of travel.

Sent from my SGH-T999 using Tapatalk


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## dacosta (Jul 23, 2010)

builtboosted said:


> does anyone notice that the rear triangle at the bottom where it mounts to the crank bearing housing is solid? how is the rear going to travel up and down if it doesnt have a second pivot point?


Hence the term "soft tail." Not a true full suspension but a hardtail/suspension hybrid. This is not a downhill machine but a full on cross country race machine. Without the lower pivot I am limited on the amount of rear wheel travel. On this design I am pushing 1.5" (40mm), very mirror compared to normal full suspension bikes. But plenty for my intend purposes.

The design is not unique as there are a few similar designs on the market today. Most notably the Moots YBB, and Cannondale Scalpel. I think Gary Helfrich of Merlin came out with the first titanium soft tail back in the early 90ies, and he is undoubtedly the king of titanium mountain bike frames. The design has been proven as either Moots/Dean/Litespeed wouldn't still be around today if it wasn't.

Its all about doing the research, knowing the materials, and doing the math that makes this possible.

Fooly


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## dacosta (Jul 23, 2010)

*Pictures in Action*

Some pictures in action.


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## eng (Apr 9, 2014)

Nice one, I just wonder how does it feel to ride it in the countryside.


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## dacosta (Jul 23, 2010)

Thanks! its a nice ride.


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## andrepsz (Jan 28, 2013)

Just typing something here to get updates on my phone...lol...Man, terrific job to say the least! I'm doing some prototyping for some bike parts myself and I understand how rewarding it is to get a project successfully accomplished! good job!


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