Uphill, Downhill, Skateboards and Steering Rods

Friday the 13th of March I spent being lucky, and fixing some stuff on the new bike. The basic result is that it's now MUCH more rideable, though I think I need to seriously shave some weight off of it. :)

The most fun part of the trip the next day was going downhill (really steep road) in traffic at 39.7 MPH (in a 45MPH zone), without pedalling (and no motor!). As heavy and low as this bike is, it handles REALLY nice and smooth at those speeds, though it's hard to keep balanced at low speeds below about 8MPH, and I end up riding in a gentle continuous side-to-side S-curve when going that slow. (I have some ideas on how to fix that)

I wonder how fast it'll be downhill once I shave a bit of weight off and put the partial fairing (top and front) on it? Here's some pics of it as it was on that day (taken by David Bluestein):


A trip to Deseret Industries thrift store to see what they had in the junk bins in the outside yard area, and found a few things, including a junky skateboard (warped, even!) priced at $1, which had pretty worn out wheels but some good (if a little rusty) bearings, made using machined parts instead of stamped thin metal ones (like the roller skate bearings I'd used for stuff before). When I got to the checkout, they only charged me for one item, and said I could just take the rest, because it all looked like crappy junk no one should have to pay for. I wasn't about to argue, as that saved me several dollars!

The bearings are easily removed from the wheels:

Once removed, they are the same size as the old ones, but much better-made. A little light oil fixed the rust problem and freed them up to roll smoothly.

To replace the poorly-made bearings in my steering tie rod, I first pushed out the old bearings from the eyes, which was unfortunately quite easy to do, even with the solder still in place on the front one. To ensure the new ones would not be able to come out, I needed to both close the eyes so they could not flex open with twisting, and cover the bottom so the bearing is enclosed by the eye and the pivot bolt's washer prevents the the eye from coming off the bolt.

I clamped the washer to the eye, ensuring they were centered and that the new bearings would be very tightly friction-fit inside the eye, barely able to be inserted at all.

Then I lightly tack-welded the washer to the eye, being careful not to heat the new bearings while doing it and immediately quenching the eye/bearing after welding. Removing the bearing, then finishing the weld of the washer to the eye left it ugly but functional.

Once the now-fixed tie rod was reinstalled on the bike, this tightened up the "rattling" and it now it steers very well and smoothly, with no jitter. Now I have a working steering solution I am confident of and can trust to both steer correctly and not come off while riding.


While checking the various bike systems and joints, etc, I also discovered the little plastic roller I'd made to guide the chain up to the pedals had begun to wear far more than I expected, as I guess it wasn't as hard a plastic as I'd thought. It wasn't all that bad yet, but it probably wouldn't last another 20 miles before it got chewed up by the chain too much to be useful. I didn't take a pic of it, though, and a few minutes after I took it off, while I was looking for parts to replace it with, Fred (one of the dogs) got hold of it and destroyed it pretty completely, making it irrelevant. :-(

So I came up with a metal roller made of the smallest sprocket off of a rear cassette, along with the leftover half of the rear hub I'd used on the motor-belt/chain power transfer axle contraption, to guide the chain the same way the little rollers in the derailer in back of a regular bike do. Works LOTS better than the other roller designs I've tried, and it isn't going to wear like they would.

I needed something inside the hub's core to fit around the bolt more tightly so it doesn't wobble, and had found a nice shiny recently-fired .45 shell in my yard (presumably from someone firing a weapon as they drove or ran down the street, but possibly tossed there by kids playing with stuff they find in the streets). I cut the shell into a few circular sections, cut at one end, and inset them inside each other and then inside the hub, which works well enough as a brass bushing.



One bad thing happened, though--I COMPLETELY forgot about a very important modification I needed to do, so I had zero hill-climbing power the next morning when I rode it out a few miles to test it on the way to a U.F.P. sci-fi club meeting at North Mountain Park here in Phoenix. It was bad enough that I had to walk it up the last half-mile or more.

The reason I had a problem was that originally I'd calculated all the gear ratios based on having 1:1 chainrings between the pedals and the main motor/pedal chainring cluster. Then I'd be shifting up or down from that with that main chainring cluster, just like any regular bike. But I had had to replace the small 16-tooth chainring I had used on the pedals themselves with a 24-tooth chainring to be able to properly fit it on there and clear certain things in the original chain path (which is different now), and neglected to also change the 16-tooth rear chainring at the same time.

Because of that, my 1:1 was 1.5:1, which meant that even in the lowest possible gear it was still a bit of an effort to start from a complete stop on anything other than flat level ground or a downhill slope! Going uphill even slightly was a very difficult proposition, and anything steeper than perhaps a 3% slope was impossible.

So I decided when fixing it today to overcompensate, and use a 28-tooth chainring on the rear to give me a 0.86:1 pedal chain ratio, which sort of makes it like I have a whole other super-low-gear for hill-climbing. If I'd had any bigger chainrings with the right size center hole, I'd've used them, up to about 32 teeth max, but 28 was the biggest I had.

Rode it around the yard, tested ok that way, but too much local street traffic today (several houses seem to be having quiet parties today), and will just wait till later to road test it.