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Thursday, April 23, 2009

Tube-and-Mesh Seat V1.0 and 1.1

After the last post, I worked some on the seat, cargo pod supports, etc, but had too many other things to do to really finish them up. Today I didn't have a lot of time either, but had to at least finish the seat a little bit so I could ride it to work.

The frame for the seat isn't anything special.

This was the way I test mounted it at first, but as I found during my ride to work, it didn't work very well as it was too far forward by a couple of inches, preventing full extension of my legs (one of the problems with the plywood seat, too).

Because the tube intersects *under* the top tube above, in order to move it back any, it had to go back at least a couple of inches to clear the top tube. I don't have a pic of it yet (the camera's card was full just as I was trying to finish stuff, and I need to back it up before erasing anything), but it really doesn't look much different from the above.

V1.0 had it laced with separate laces on each side, between the edge of the mesh and the tube.

This didn't work very well, as I simply couldn't get it tight enough to not slip down, and it wouldn't keep me from banging on the tubing below for more than a few seconds.

I also cannot find the brass eyelets I had to make this seat with, so I ended up having to use an old worn-out soldering iron to *melt* holes in it, such that the edges of the holes in the nylon mesh are solid, to keep the cords from ripping thru the mesh.

That part actually worked fairly well, for now. As soon as I find the eyelets I'll put them in, though, because I'm sure this won't last long like this.

V1.1 came pretty quick, where I unfolded one layer of each edge, so it would be wide enough to go beyond the edge of the 19" wide seat tubing, and be able to lace shoe-style around the tubing instead.

This works MUCH better, and aside from not yet having it tight enough, lasted almost the whole ride to work before beginning to sag.

After I got home, I took the seat off and sat there for a while tensioning the cord (parachute cord from a box of assorted stuff I got from's mailing lists last year). Starting from the front/bottom edge, I pulled each diagonal as if drawing a bowstring, then pulled the next diagonal to take up that slack, and so on all the way to the top end of the seat. I can get a semi-musical tone from the bottom half of the cords, they're so tight now.

Works very well so far. We'll see how the next few days' rides go.

I didn't have time to put the cargo pods back on, so I rode it with a backpack hanging off the top rear tubes of the seat. Since I didn't have the pods, I also couldn't carry the batteries. Without that weight, the bike is still pretty easy to ride, as long as the motor gearbox clutch is disengaged.

I also did end up using that heavier square tubing on the bike--I needed *something* that would make a good seat mountpoint that was parallel, flat-surfaced, etc., and the only good way to do it was with either L-shaped bar, or the square tubing. The latter was lighter by a fair margin, and stronger in torsion, so I just used it as I would have for the bottom ones, on the shorter top bars--that's the rusty bars across the top of the rear wheel.

They stick out in back just about right to use for a trailer hitch mount, too, made from that black fork I have on the upright Columbia bike right now. Might even be able to make something lighter and just as stiff; I'll get to that after I build the flatbed trailer for this bike, which is probably weeks away unless I come up with a sudden real need for it.

More pics in a later post, showing how the seat now looks, as well as the permanent lighting setup--the one above is just zip-tied into place, as I only had a few minutes left before I had to get to work. :-( The way it is now is much more interesting (read: strange) but more functional and more visible. The way it was in the pic above created a problem hanging the backpack on there, because it blocked the taillight and brake light, though not the two scooter turn signals.

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