# Squishy bike. Frame #2.



## shirk (Mar 24, 2004)

PAD - Paper Aided Design









Old school Solidworks modelling.









Gluing it together with fire.









Jigs? We don't need to stinking jigs.









Walt gets credit here. His "What would I do different" comments on his 29'er DH singlepivot talked about using a 44mm headtube. Worked great.









Clearance is "Tight like a tiger". Single ring only, trendy just like the big guys are doing on their carbon bikes.









No machines were harmed in the making of this bike.









It's not pretty, but it worked.









Rattle can hides sloppy noob work.









Long, low, and slack.









Final frame weight was 3.39kg without shock or rear axle. Total as built in picture is 14.41kg.

ht - TT 44mm
tt - Nova 31.7mm .8/.5/.8
dt - Aircraft Spruce 38.1mm 0.889
st - TT 34.9mm
rear swingarm is 25.4mmx0.899mm with the lower portion of the elevated being 19mmx0.889mm

The leverage ratio came out feeling very linear, doesn't blow through travel with the LV RP23. The shock has a low compression tune and I am going to try something with a medium tune to see how it feels.

I've got a couple of big days in the saddle on it and no major complaints. It was originally designed as a full our "EWS race" bike. I wanted to have it done before racing the EWS in Whistler but I missed that goal. For that style of racing I think I am really close to ideal geo/fit. I'd like to shorten up the rear end to get a bit more loft out of the front.

Next up is a more trail/AM friendly version. Playing with actual CAD software this time and working on a beam style jig in 80/20. LOTS of headaches trying to build that rear swingarm without a jig.

Thanks again to all the guys that have shared knowledge on here over the years.


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## Eric Malcolm (Dec 18, 2011)

:thumbsup: Nothing beats building your own.

Eric


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## frankzetank (Feb 5, 2013)

Nice! Thanks for the inspiration to accomplish complex projects with simple tools! 

Enjoy the ride!


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## ktm520 (Apr 21, 2004)

Nice man! How much rear travel?


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## shirk (Mar 24, 2004)

It has 157mm of rear travel.


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## Feldybikes (Feb 17, 2004)

Homemade full squish FTW!

I'm interested in how you ended up having the pivot come together.

Also, none of my business, but in case you're interested, they do make clip on welding shades, since you wear glasses. I used to use 'em (along with didymium glasses) just for sparking and adjusting the flame, then flip them up. I find I leave them down all the time for brass and flip up for silver.


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## golden boy (Oct 29, 2008)

Congratulations Shirk! Very cool that you took on a full-susser for #2, and without a jig to boot. It has a nice, clean look to it. Thanks for sharing!


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## todwil (Feb 1, 2007)

Cool bike I was following this thread on that other site!


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## Montanadan (Sep 19, 2014)

shirk said:


> PAD - Paper Aided Design
> 
> 
> 
> ...


Wow...this is so impressive to me. I've done my fair share of welding/fab work, and this still blows me away. Someday I may try to aspire to this.


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## ktm520 (Apr 21, 2004)

Hey shirk, how has the frame been working for you? I think my next one is going to be a monopivot dually. It would be really cool to completely get away from riding production frames and I've got to have at least a 5" travel bike in the garage.

What specific headset did you use for the pivot? My other thought is to use Santa Cruz Superlight hardware for the pivot and turn a custom pivot shell.


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## shirk (Mar 24, 2004)

ktm520 said:


> Hey shirk, how has the frame been working for you? I think my next one is going to be a monopivot dually. It would be really cool to completely get away from riding production frames and I've got to have at least a 5" travel bike in the garage.
> 
> What specific headset did you use for the pivot? My other thought is to use Santa Cruz Superlight hardware for the pivot and turn a custom pivot shell.


It was an FSA 44mm headset. I got lucky that a local shop had one of the older versions that was 44mm inset upper and lower for 1 1/8th steer.

This is the same headset as I used.

FSA Orbit Z 1 1 8" 44mm Semi Integrated Headset Threadless w Top Cap Black | eBay

You'll need an extra split compression ring.

The frame has been riding great. I've done some big rides on it with no issues. I don't baby it, the bike gets ridden hard in the rain and just put away, sometimes hit with the hose and just hung up.

I am planning to build another one soon. I want to make something less EWS enduro race geo and more trail friendly. This one is really long and slack, it's as long as many XL dh bikes yet.

Design wise on the next one I might move the pivot back and do an offset seat tube. Also looking at a non elevated chainstay design. Recently started learning how to use FreeCAD so it's in the drawing stage.

Also going to do a jig in the same manner as yours. I had a hell of a time doing the rear end.


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## ktm520 (Apr 21, 2004)

Very cool shirk. Did you put much thought into the shock orientation and the resulting leverage curve. Looking at your pics, it appears to be more toward the progressive side.

I've been working on a little 2d layout and it should be pretty easy to get a linear with slight progression curve. I never have understood why Santa Cruz likes digressive leverage curves so much.


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## ktm520 (Apr 21, 2004)

shirk said:


> It was an FSA 44mm headset. I got lucky that a local shop had one of the older versions that was 44mm inset upper and lower for 1 1/8th steer.
> 
> You'll need an extra split compression ring.


An alternative would be to buy two upper Canecreek's. It looks like the stack height is lower for CC compared to that Fsa by 9mm as well (16.9 vs 8), if that ebay description is right. That is probably a little off.


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## ktm520 (Apr 21, 2004)

How did you keep the swingarm bosses tight on the pivot spindle? Pinch bolts?


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## shirk (Mar 24, 2004)

I did some playing around in Linkage to try and get linear to progressive. I got a good enough idea of where it would need to be then just kinda winged it. I think it turned out with a bit of progressiveness as it does not blow past the end of it's travel.

Pretty sure that 16.9mm spec includes top cap or is just inaccurate. I am not running any caps on the bearings. Stack would just be the width of the lip on the cup then maybe a 0.5 mm for the height the split compression ring sits above the cup. I wanted to have the shell as wide as possible.









Here you can see the top cap almost acts as a inner chain guide. There is not much room in there with the chain on and in the tallest gear. Would be neat to mill a custom top cap that acted as a mini jump stop guide.









Pinch bolts are used on the pivot spindle. A friend machined them up for me and I brazed them on. Once brazed on I then cut the stem tube/nut combo to create the half pinch unit. Funny story is that the bits of tube to make that pinch system came from an old brazed Salsa stem that a friend gave me, he bought out an old bike shop and it was a NOS stem that he gave me a number of years ago. It got hacked into bits and stripped of it's paint for this.


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## ktm520 (Apr 21, 2004)

shirk,

Any updates? Have you put some miles on this frame? Did you use a thru axle on the rearend? I'm rocking back and forth between going with some simple plate drops like you used and boning up for x12 drops.

I'm starting to gather parts for mine. Will start a thread here shortly.


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## shirk (Mar 24, 2004)

I've got a ton of miles on it. 

It is a ghetto 142 thru-axle rear end. The plate dropouts have holes drilled in them and I just sandwich the 142 hub, no fancy lip for it to sit in. It is a bit of a pain to take the wheel in and out. 

I don't notice rear end flex when I am riding, but when you grab the wheel and move it there is more than I'd like. 

v2 I've draw up a rear end that is triangulated instead of elevated chainstays. 

The pivot is stout, no bearing issues. Needing to do caps complicates things a touch but it's not the end of the world. Again for v2 I've draw up a part that I will get a friend to machine that will make it cleaner. Basically plates that tie the pivot to the uprights and the chainstays. 

Shock rate feels really good, I still need to put a better shock in there and really get it dialed. Leaning towards a CCDB CS for the adjustment range. The new Fox X2 would also work. 

Since those original pics I've gone to a 40mm stem and an 160mm Suntour Auron RC2. The 160 is taller than my old Fox 150 36.


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## Drew Diller (Jan 4, 2010)

I might have creeped this thread repeatedly.

I'm working on a fully. #7 for me. You know how many people give me this _look_ when I tell them what I'm aiming for?

GGGRRRRRAAAAAAAAHHHH F*CK THAT SH*T

You made a fully as your *second* frame. I mean that's amazing.

Here's a guy who could do it, and he did. I hope I refer back to this thread later after someone insults me again, it'll be all _look at this guy's bike, in yo FAAAAAAAAACE_


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## shirk (Mar 24, 2004)

Hey uh thanks.

I honestly don't know why people are so scared of making a full suspension frame. The actual work ie brazing and mitering the tubes is the same. The 44mm headtube pivot is super sweet as no special machining is needed. 

Go for it. Build it. Ride the living daylights out of it. I have.


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## Eric Malcolm (Dec 18, 2011)

Drew, you finally building that Sus'er?

Don't give in to those mockers, they don't matter. What matters is that you enjoyed yourself doing what you love.

I turned up for my first MTB ride/event on an old 1992 Marin rigid with cantilevered brakes and 7-speed freewheel. Got laughed off at the start, kept asking them red faced puffing sweat wheelers if the pain levels were sufficient, then rode away. Satisfaction isn't measured by who made it or how fancy it is but by how you handle it.

Keep cool.

Eric


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## shlammed (May 19, 2015)

what bearing/bushing and pivot did you use in the 44mm HT pivot?


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## shirk (Mar 24, 2004)

shlammed said:


> what bearing/bushing and pivot did you use in the 44mm HT pivot?












This is a pair of upper 44mm inset headset cups pressed in. Then I used a length of 1 1/8th steer tube as the pivot axle. The angular contact bearings do a great job in the pivot.

The steer then has a starnut pressed in each end and endcaps are used to pre-load the bearings.

Just think of taking your headset and moving it to a pivot.


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## Feldybikes (Feb 17, 2004)

Out of curiosity, have you taken the pivot out ever? Since you're using two top headset cups, each split collar is going to press in and (in theory) not want to press out. However, I would guess that it practice a little rattling it around and it would loosen up.


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## shirk (Mar 24, 2004)

A little tap on the axle with a rubber mallet unseats the split ring just fine. Slide the one side split ring off and remove axle. 

Again same as a headset, I've had to tap a steer many times to unseat a split ring and it's never been an issue.


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## Feldybikes (Feb 17, 2004)

Pretty much what I thought. Thanks.

To clarify, the difference with the headset is that when you tap on the top, the fork falls out the bottom. In this case, when you tap of the left side, the right side (theoretically) just tightens up and doesn't actually move enough to let the left side loosen.


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## shirk (Mar 24, 2004)

The split ring on the side opposite that tapping always stays with the axle. So as I drive the axle from the left it loosens the ring on the right. 

It takes very little to unseat the split ring, then it can just slide off the side opposite the tapping.


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## Feldybikes (Feb 17, 2004)

Of course you're right. I was totally thinking of it sdrawckab. I think I'm getting dummer.


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## shlammed (May 19, 2015)

does the swingarm clamp to the short portion of the steerer tube "axle" like a stem would on the steerer tube, is the swingarm a solid part that this is just a skewer for and it doesn't need to clamp this pivot point or is it just the star nut holding it in place?

Edit: reread thread and found my answer there. there are pinch bolts.


interesting.
If you had a drawing of the frame, or just a list of the specs you used to build it, I would love to have a peek. I will likely be building something like this for myself at some point.

Cheers
Matt


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## shirk (Mar 24, 2004)

I did a full scale drawing on my drafting table that also doubles as my work table. Not sure what seeing it would help you with. All the fit and geo numbers are specific to me and my wants. 

The suspension geometry I worked out with cardboard bits to replicate the rear swingarm. I knew from playing around in Linkage roughly where I needed the shock mounting points to be to get a decent leverage curve.


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## shlammed (May 19, 2015)

just a project I am undertaking. putting a bunch of geometries into CAD and seeing how they compare.

aka nerding out.


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## cerebroside (Jun 25, 2011)

Looks like you made the Pinkbike frontpage: Pinkbike - Crankworks Whistler Randoms 2015.


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## Feldybikes (Feb 17, 2004)

whoa. that's pretty rad.


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## Walt (Jan 23, 2004)

Congrats Shirk!!!


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## ktm520 (Apr 21, 2004)

Very cool! Congrats man.

You planning any geometry/travel changes for v2.0?


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## shirk (Mar 24, 2004)

Thanks.

Pretty stoked to see my garage hack build on Pinkbike.

This frame was originally planned for the 2014 Crankworx EWS, really happy to finally ride it in the 2015 EWS and have it feel great.









GLC drop at the end of stage 5.









Shot from practice on Saturday pre-riding Top of The World for Stage2.


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## Walt (Jan 23, 2004)

That race looks amazing. Gotta get my kids up and shredding and make a family vacation out of it... unfortunately they are 1 and 3, so it'll be a while...

There is nothing more fun than building something and then riding it on awesome trails!

-Walt


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## shirk (Mar 24, 2004)

ktm520 said:


> Very cool! Congrats man.
> 
> You planning any geometry/travel changes for v2.0?


I have two bike planned to replace this one.

A more trail oriented bike with less travel. It will bring the wheel base back into something reasonable and steepen up the ha. Also thinking a shorter travel shock.

The other will be similar to this one, 160ish travel and still as slack. Shorter chainstays to get it a bit more playful in lofting the front end. A touch shorter in the reach and a bit more stack. I found that for the steep local courses I have had to add 20mm of spacers under my stem, I'd prefer no more than 5mm being a "custom" frame it really shouldn't have a stack of spacers. Also will look at going to a longer shock but need to do some research to see if it's worth it. Currently using a 7.875*2.25


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## shirk (Mar 24, 2004)

Walt said:


> That race looks amazing. Gotta get my kids up and shredding and make a family vacation out of it... unfortunately they are 1 and 3, so it'll be a while...
> 
> There is nothing more fun than building something and then riding it on awesome trails!
> 
> -Walt


If you've never been to Whistler it really is mtb paradise.

I have a 10 week old little boy so I've been off the bike for about 12 weeks leading into the event. Felt great to get a weekend of riding in again. Hurt like hell trying to push on the pedaling sections. No snap in my legs.

I placed 15th in the 30-39 amateur class, pretty happy with that. Last year I was 19th and 10:23 behind the class winner, this year I knocked that down to 7:35 (the winner is my friend that is ahead of me in the pre-riding shot above a Whistler local). Cut some time off and I think some of that can be attributed directly to the bike.


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## ktm520 (Apr 21, 2004)

Right on. That is the same approach I'm leaning towards. I've decided to dial my frame back from 140 to 120 because that better suites 95% of the riding I'll do with this frame. I'm lucky to hit a park once a year and even shuttling doesn't happen that frequently for me anymore. To much driving involved to get to those trails. The big killer is that I don't a 140/160 fork right now and really don't won't to buy one. I do my own revalves so I'm really picky when it comes to forks and Manitou doesn't currently have anyting in their lineup that fits the bill.

A few things to consider on the shock. At 160 with a 57 stroke, you are on the higher side of leverage ratio. This gives you lower shaft speeds which equals cooler temps, but can be harder to tune, if you do you're own revalves. Jumping to a 63 inverts those characteristics. But really, it's not that big of deal. I'd look more at what options it gives you when shaping the leverage curve. With a 63, you'll end with a straighter curve. Or the big factor for me is economics. If I have a 57 shitting on the shelf, I'll design around it.

Your current bike has both a long front and rear end, and this gives ample room to shape the curve anyway you want. As you start shortening the front and rear, the possible shock orientation start moving toward the flat to flat-regressive side of the curve shapes. That's the comprise I had to make with my frame have 29 wheels and 415 stays.


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## shirk (Mar 24, 2004)

This was build around the 57mm as that is what i had, then I ended up buying the CCDB Air CS in that size. Was thinking more today and not sure now if I should do two bikes...I do enjoy riding the hardtail in the wet winter months and I don't have any issues pedalling around the slightly extra weight of the 150+mm bike. If budget for build kits wasn't an issue I'd build all three (new HT and the two fullys). 

The great think about the CCDB is no need to revalving a shock. I kinda wonder now that Fox has the X2 if RS will be coming out with a new replacement for the Monarch with more external tuning range.


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