# Not Another Fat Bike



## Clockwork Bikes (Jun 17, 2006)

Started my first fat bike today. Mostly just to try it and due to a little peer pressure.


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## G-reg (Jan 12, 2004)

Well, you have my attention!


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## J_K (Jan 18, 2010)

G-reg said:


> Well, you have my attention!


Ditto!

That fork is very nice! I really like how you do the bends on the lower part of the legs.


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## Testmule (Jul 27, 2013)

J_K said:


> Ditto!
> 
> That fork is very nice! I really like how you do the bends on the lower part of the legs.


And what material you're using?


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## 88 rex (Aug 2, 2007)

Joel, beautiful work as usual! I'm guessing SG 4130 for the legs? 

Question on the steerer though. Any particular reason you went with a tapered steel steerer? Purely aesthetic? It's my understand that it was a Engin/Paragon creation for tandem use. Seems overkill, not that there is inherently anything wrong with overkill. Just wondering, that's all.


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## Clockwork Bikes (Jun 17, 2006)

The legs are 1" x .049" 4130 tube, 3" CLR and the crown pieces are 1.125" x .058" that I normally use for 1" LD stems.

I used the steerer just cause I wanted to try something new and it looks more proportional. This bike is all about trying new things. The steerer is way overkill for this bike but also for tandems.

This is the legs being bent. The crown pieces are done on a draw bender by a vendor.



















Thanks, Joel


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## todwil (Feb 1, 2007)

Cool lookin fork!


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## Feldybikes (Feb 17, 2004)

The first picture hurt my brain: miters 90 deg out of phase, and I couldn't understand it. Scrolling down to the assembled fork kept me from having an aneurism.


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## Meriwether (Jul 26, 2007)

Awesome Joel! That's such a sweet fork! Looking forward to the rest of the build...


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## Drew Diller (Jan 4, 2010)

Sweet, I was hoping you would make one eventually. Looking forward to it, looks great so far.


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## afwalker (Apr 26, 2012)

That bender is making me jealous, that's a tight clr for 1" tube. Diacro #3 perhaps?
cheers
andy walker


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## Clockwork Bikes (Jun 17, 2006)

Moving along. This will be a no-file frame to greatly speed progress.


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## TrailMaker (Sep 16, 2007)

Hey;

Nicely crafted, of course. I hope someone rides the crap out of it. I'll be interested to know if the SS/ST junction can withstand it.


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## Meriwether (Jul 26, 2007)

Very cool. Can you divulge the approx radius on that seatstay bend?


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## Clockwork Bikes (Jun 17, 2006)

The ST joints are plenty strong. It's not a high-stress area and plenty of bikes have a lot less holding them together.









The top bends and bridge are 3" radius and the bottom are 10".

-Joel


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## Eric Malcolm (Dec 18, 2011)

Joel makes a good point regarding seat-stay attachment. In fact, all earlier frames for the first half of the bicycles life were done this way. Although I had a Holdsworth Super Mistral as my first purchased frame in the early 1970's that was a Fastback, the current jointing did not really appear until BMX, then Mountain Bikes had it as standard practice.
This does not mean that the old style is irrelevant, it just seems to have been 'lost'. There are some really tight build situations where perhaps consideration to side attachment could/should be looked at again. 

Eric


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## todwil (Feb 1, 2007)

Looking good Joel can't wait to see it assembled!


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## Walt (Jan 23, 2004)

I've done stuff very similar (albeit with less extreme bends) and I can say definitively that it'll be fine. You can practically make the seatstays from balsa wood and hold them on with twine and they still work. English uses like 12.5mm x .028 or something for his. 

Really not an issue, and as others have pointed out - even pretty small surface area silver soldered butt joints on the sides of the seat tube is plenty enough that I've never seen one fail. There must be tens, if not hundreds of millions of bikes built that way, too.

-Walt


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## FTMN (May 10, 2010)

Clockwork Bikes said:


> Started my first fat bike today. Mostly just to try it and due to a little peer pressure.


Is it for you, or for a customer?


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## Clockwork Bikes (Jun 17, 2006)

FTMN said:


> Is it for you, or for a customer?


It's for me. I've gotten a few fat bike quote requests and have declined them since I've never made one. I'll call this R&D and take the tax write-off.


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## frankzetank (Feb 5, 2013)

Clockwork Bikes said:


> Moving along. This will be a no-file frame to greatly speed progress.


Ahh!! Your no-file fillets look better than my filed ones! Great work and craftsmanship; as always.


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## TrailMaker (Sep 16, 2007)

Well...

For those more familiar with Fatbikes, Surly has quite apparently had some different experiences with that junction than everyone here. I'm not sure anyone knows why. It may have had nothing to do with the tube layout, but they had a rash of failures... like almost every frame made, for a while. I would not have thought being fat would have made any difference, but it was only on the Pugs, so... Just curious.


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## smudge (Jan 12, 2004)

TrailMaker said:


> Well...
> 
> For those more familiar with Fatbikes, Surly has quite apparently had some different experiences with that junction than everyone here. I'm not sure anyone knows why. It may have had nothing to do with the tube layout, but they had a rash of failures... like almost every frame made, for a while. I would not have thought being fat would have made any difference, but it was only on the Pugs, so... Just curious.


Interesting...I wonder why. Perhaps a batch of them used a tube with too thin a wall where it counts?

Great looking build Joel.


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## Damon777 (Jun 11, 2012)

Nice bike, and I like the bender, too.


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## Clockwork Bikes (Jun 17, 2006)

Done! To the painter on Monday. They use a really cool primer from PPG made for Airbus to coat the inside of fuel tanks. It just happens to be Clockwork green and is super tough. Example.














































-Joel


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## J_K (Jan 18, 2010)

Amazing!
what size tyres it will take?


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## aerotugpilot (Dec 1, 2010)

That is so gorgeous it is making my head hurt. Simply stunning.


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## Meriwether (Jul 26, 2007)

So cool, love the racks! You can go fill up your tanks with that thing


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## Clockwork Bikes (Jun 17, 2006)

J_K said:


> Amazing!
> what size tyres it will take?


It's designed around Surly Nates.


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## m-gineering (Feb 5, 2012)

Clockwork Bikes said:


> The ST joints are plenty strong. It's not a high-stress area and plenty of bikes have a lot less holding them together.


Only thing is you made it a high stress area! With straight stays the braze joint is only loaded in shear, but to get clearance you've changed the joint design with a great big lever. The bend in the seatstay will flex if the stay is compressed, and the stress in the joint will be very uneven. The bridge triangulates things a bit, which helps though
/Marten


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## TrailMaker (Sep 16, 2007)

m-gineering said:


> Only thing is you made it a high stress area! With straight stays the braze joint is only loaded in shear, but to get clearance you've changed the joint design with a great big lever. The bend in the seatstay will flex if the stay is compressed, and the stress in the joint will be very uneven. The bridge triangulates things a bit, which helps though. Marten


Yes;

Quite possibly what Surly has discovered. I'm not saying the OP design is destined to fail, just that there is some precedent for problems in this area, that Fat might be a unique contributor to that, and that past precedent does not always play out, especially if it misapplied. The Surly stays cracked around the welds, on the inside of the weld joint, I believe. I imagine that this may be a result of the angle at which the stays are coming into the SS creating a side twist in the joint back and forth, over-stressing the ST. The second notion is that - since the cracks were always on the inside of the stays - that this same approach angle saw each stay bowing outward under linear compression, spreading the two simultaneously, and cracking the insides.

Whatever the cause, it is interesting to speculate.


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## davesauvageau (Jan 8, 2010)

BEAUTIFUL! I'm digging the cable guides and that headtube! Keep it up Joel, you always make me stop and stare!


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## Clockwork Bikes (Jun 17, 2006)

*Pics!*

Turned out pretty nice. I could've brought the rear wheel in closer but unfortunately I started the frame before I had the wheels and used internet tire specs. The racks also accept Ortlieb panniers. All fillets have not been touched with a file.
































































More pics: Flickr: Joel Greenblatt | Clockwork Bikes' Photostream

-Joel


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## J_K (Jan 18, 2010)

Yeh, I'm speechless.
That thing is a beauty, but what else you would expect from Joel!


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## aerotugpilot (Dec 1, 2010)

Amazing. Are the rear dropouts spaced at 170 or 190mm?


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## Clockwork Bikes (Jun 17, 2006)

aerotugpilot said:


> Amazing. Are the rear dropouts spaced at 170 or 190mm?


170mm


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## todwil (Feb 1, 2007)

Holy Shite Joel very nicely done!!!!


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## G-reg (Jan 12, 2004)

Love it, the former aircraft mechanic in me double loves the color. Shouts "Function before Form!!"

Details on the front brake hose routing? I think I've had similar things in mind but have yet to execute. 

I had blown off the gumwall Nates as a way to charge folks 3k for a Pugsley.....But damn with the rims and Zinc Phosphate they really look snazzy.


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## Clockwork Bikes (Jun 17, 2006)

Thanks, everybody.

You can see how I did the internal fork routing here. The fat steerer makes it possible and there's no extra drag in the cable.


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## Meriwether (Jul 26, 2007)

Raised the bar, wow...


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