Discussion in 'MBBO 2016 BIKES' started by tjwilson, Sep 7, 2016.
Thanks, that's quite a compliment.
To be honest I've been so concerned about the strength up and down that I haven't really considered side to side forces. It seems like that is were there might be an issue with the dimpled tubes. Not sure, I'm not an engineer and am just building by best guess. True though that dimpling of tubes for clearance on factory frames are (always?) horizontal along the tube instead of vertical? Once I have the frame complete I plan to take some measurements and run the bike through a few cautious test rides. I'll remeasure to see where and if there is any movement and then if required plan additional reinforcements. The good thing is that there is plenty of room on the inside of the stays to add material. The bad thing, it could potentially be a very short test ride!
After the rest of bars are there I'm sure you'll be able to even torque test it to see with the clearances u have going on .
I just checked my cranbrook.. the seat stays have no dimples... They are carrying the weight and load to the rear axle, top brace is a bit past the dimples of the chain stay.... In your case it's more like a fixed swing arm as far as how load will transfer.
Latest progress, bending the side stays. Symmetry is hard! They ended up closer to each other than the image of the tubing in the bender would indicate... close enough anyway. I added a plug to one end, packed the tubes with sand, plugged the other end, and welded the tubes together. Then I ran the twin tubes through the bender. (Probably important to note that I made sure that the plugs didn't seal the ends completely. This prevented pressure from building up in the tubes as they were welded.)
Bottom end reinforcement. I'll weld this in place after cleaning up the previous welds.
Side stays in-process and in position. I plan to make some adjustments. The rear end of the side stays will be trimmed and the sides rotated a bit. The upper ends will be trimmed and tube extensions added to follow what will be the bottom edge of the seat. I'm also thinking of tapering the tube from 3/4" to 1/2" along that edge and shortening the seat length a bit. These are the handlebars that are the winning choice... so far.
Love the flow of this bicycle it is unique for sure. Looks nimble
And there it is... Awsome..
Love those curves!
update update update...
sent from a crowded phonebooth...
Not a lot to update, was out of town this past weekend. Did get a start on prepping some of the pieces that will probably make their way into the side / seat stays. Also worked up a digital mock-up to experiment with how much I want to shorten the seat and refine how the seat flows into the side stays.
Here's a pict of the pieces and parts. The tapered pieces are donor chain stays, .75" to .5". Really thick wall, .120" x .5", tubing was used for the tight bends. These will be for the back of the seat, maybe. Might try for a tighter radius. The two longer bent pieces are .049" x .5". These were filled with sand, plugged, welded together, and sent through the bender.
This side view has the pieces in approximate position. For comparison the left side shows the pieces in mock-up, right shows the existing frame end digitally removed and the intended seat profile added.
No picts but, pulled everything apart last night and cleaned up the welds that will be hard to get to once the side stays and bottom brace are welded on. I've got time set aside this coming weekend so hopefully there will be more to show soon.
Really nice frame! i love how the seat flow with the top tube and there is nothing under it , makes it look light and fast
WOW!!! What a curvy work of art!!!
It's so surreal it is sorta like a Salvador Dali build!
Yep. All it needs are wheels like these....
I think I have some like that in my parts pile...
Flashback -> Daliesque -> "Persistance of Memory"
Oh how I wish I could say that was intentional.
A little weld clean up. Most of the tubing is relatively thin .049" wall so I was a little concerned about doing too much smoothing. Just enough to keep the filler from having to be too thick.
Most of the weekend was spent working on the seat/side stays. I started by making a cardboard template to find the angle of the curved sides extending back to the end of the seat. Then I tacked the pieces and parts previously bent together using the template as reference.
The sides were trimmed and solid rod inserts were used between the sides and the new seat base.
The frame backbone was trimmed and new pieces bent and cut to tie the end of the seat to the frame.
Next up will be final welding the tacks!
I like that shot between the handlebars. Symmetry.....
That's one smooth looking beast. Looks quick even when still. Excellent design
Excellent metalwork sir!
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