dogman wrote:I didn't like much the extra length of your first try, where you connected the head tube of one frame to the seat tube of the front frame.
I ended up not liking it either, if you mean the schwinn sierra front /trek 900 back plus orange swingframe rear.
Would still work for a bolt-together, that I may someday still do just to see if it is possible. Someday.
Love the big shock! I may have to get an air shock on mine if I really load it up. For street though, 1 inch of travel will be enough to prevent broke spokes.
If I had a smaller *working* damper, I would use it, but these big orange ones are the smallest ones that will do any good.
But the spring that is on there in that pic is not the one to be used--instead it'll just be an 850lb MTB shock (whcih is harder than the one that came on these). At least, that's the theory. Should be a pic of the new method in that thread's last page or two. Twin MTB shocks would work if the dampers I have were working (might be fixable, have to figure out how to open them up). I think I'll get up to two inches of spring action this way, maybe, but I forget how much vertical travel taht will actually give. 3 or 4, I think. (including whatever sag there is from bike/rider weight and load)
I dorked around with it some more last night, and found I will need to rotate the whole rear frame down some, possibly a lot.
So that the cut-off front end mates up with the back of the seattube? If possible, grind out slots so that you can butt it up right where the seatstays meet the back of the seattube, so all the force is transferred into the toptube. Much stronger than if you put it above or below that point.
What I really dug about this one, was the way the bottom bracket fits right into the rear dropouts nearly perfect. With some grinding, I could even bolt on.
As long as you use hard washers between the square BB spindle and the dropouts, it would work. Someone pointed that out to me on my own attempt at this.
I am planning though, to weld it. I'll have nice fat thick steel even I should be able to weld. Should be very strong.
Since you won't need the BB to turn at all, you might want to first tighten up the BB cups really hard, so that there can be no wiggling of the spindle. Also check if they are plastic retainer rings and replace them with metal ones or remove and weld them in, before you do the welding on the spindle-to-dropout connection. Otherwise it might start coming apart later.
Because I like saving things for other uses, I'd probably cut off and save the entire BB shell unit for a jackshaft for something, or spare parts for regular BBs, and just weld a set of tubing or plate from the dropout area to where the BB used to be. AFAICT, the only things that mount to the part you'd be removing are the derailer for the cranks and the kickstand, neither of which you'd be using on this bike. (better to use a different kickstand and mounting place)
What will be interesting, is if it can handle at all, or turns out to be a death wobble bike. I do expect to have some tail wag. I might end up with a lot of extra metal added on later. I'm thinking of how I can turn the rear rack panniers into extra bracing the entire length of the bike.[/quote]
This is one way you can minimize wag, and make the rear rack a lot stronger:
On teh right is a "rear view" of the rack, which would have an X brace across it's top, and a short one at it's rear, so it would be just above and behind where the rear tire would be at full bump.
The extra bracing wouldn't add much weight if you use small-diameter tubing, like seatstay/chainstay stuff, and still be very strong. Could be uber strong if you use old ten-speed top and downtubes, but many of those are thin-wall and hard to weld without burnthru (at least for me with my crappy HF welder, which I am damned sick of at this point). But the stays on them seem to be thicker metal for the smaller diameter. Especially on the cheap ten-speeds. If you get the really tall bikes, like for 6-foot-plus riders, the stays are super-long. That's where I got my thin tubing for the currently-in-progress bike.
If you prefer, you could mount the tubes like this instead, for bracing across the entire top of the bike (also usable to mount batteries from in the triangle, but they will be in the way of your legs while pedalling):
The thing I don't like about this is you don't get that nice V of a rear rack, unless you start spreading it out before the seattube, making it wider at that point than your legs may like. This is one of the problems I had trying to figure out how to do the cargo rack on mine.
Since I don't necessarily need a rack across the top of the wheel on mine, just the boxes or bags on the sides, I planned mine like this:
where it will come to a point in the rear (view from the sides) and have space for an X brace behind the wheel for anti-wagging (I hope).
Oh, here's the pic of the shock as it currently is:
with the post about it and more pics here:
http://www.endless-sphere.com/forums/vi ... 76#p389876