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Discussion Starter · #1 ·
And frame #2 is done! This time around, I went for a full suspension bike.

I wanted a high-pivot bike and I wanted to keep it single pivot to simplify maintenance. As it ended up, it's basically a single pivot, but with pullrods to reduce the shock's effective eye-to-eye length in order to be able to package it (kinda) vertically. This only adds 2 additional bearings, bringing the total up to 4 (plus 1 shock bushing, at the lower mount), so the bearing count is still low compared to other designs.

I designed the kinematics using a homemade spreadsheet, aiming for 100% AS, or a little over, around the sag point in the larger cogs. I was also aiming for as linear a motion ratio as possible ( I ended up with about 6% variation over the whole range).

The frame is chromoly for both front and rear triangles. I'm not super good at documenting what I do, but I do have a few pics of the build process which I included below.

Specs:
~63° HTA
~77° STA
450mm reach
~350mm BB height
435mm chainstays
160mm F/R
 

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Discussion Starter · #4 ·
Thanks Walt! It's appreciated.

Shirk, here's a video of the suspension cycling:


Basically, the pullrods don't move relative to the shock. They're bolted directly together up top at the trunnion mount, and there's a bearing at the lower end where the pullrods connect to the rear triangle.
 

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Awesome Build! I want to make a high idler bike for my next build. I used a similar method for the front triangle jig, seems to be a easy and inexpensive way to build a jig. Let us know how it rides!
 

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Discussion Starter · #7 ·
Yeah the front triangle jig worked super well and was really easy to make.

I took the bike out to Highland & Burke, as well as a couple of days in local trails, and I'm super happy with how it turned out. The high-pivot rear end and the super slack front make it a real tank, it just wants to plow through everything. Surprisingly, it climbs pretty well; the steep STA keeps weight on my front wheel. I'd even say it's an overall better climber than my old bike, a 2014 Devinci Atlas. Although I can definitely feel the extra drivetrain friction, the slower handling makes it easier to point the bike where I want it to go, and I haven't had any issues with wheel flop. I'm super happy with it so far!
 

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Discussion Starter · #10 ·
The bike is still going strong! It's been my main ride this season, with on average 3-4 rides per week. Structurally, there haven't been any problems with welds, undersized tubes, etc.

However, I did kinda gloss over bearing protection in the linkage, so the tiny 608 bearings connecting the shock plates to the rear triangle are finished and will need to be replaced.

All in all, I'm pretty satisfied with the results.
 
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