Search all of my sites with Google

Monday, May 4, 2009

Phirst Phriday Phoenix Phreaks Ride

After fixing the motor, I had one other problem to fix--the rear tire was sunrotted (remember, this is all salvaged junk!) and the cracks bulged enough under the load of the bike, batteries, and me to make me worry I'd get a sidewall blowout of the tire itself, which would then let the tube shred itself against the frame, most likely.

I *had* pics of all this stuff, but something happened to the camera card on insertion into the computer to read it, and I ended up having to format it to use it at all. :-( So I took some pics of the things I could, to at least give an idea of what I'm talking about.

The tire itself was easy to replace, as I have a number of 24" tires. None are road tires like I'd prefer, but some are in better shape than the ones that came off the Roadmaster bike, and one is less knobby, and not quite as wide, with a completely solid center 1/8" or so for a bit less rolling resistance.

These are a couple of the ones I have, all are fairly similar, except others have even less continuity between center treads. One looks more like a waterfall scoop than a wheel. :-(

The one on the left is the actual rear tire I was using.

This is the tread on the one I now have installed.

As you can see, it's more continuous in the center, which hopefully reduces rolling resistance a bit. I couldn't really tell a difference, at the same 50PSI I keep them at, but the bike is really heavy with the batteries and motor, so it's possible there is a difference I could feel if I had just the bike and no motor/batteries/pods on there.

Changing the tire should have been quick and easy, but as things tend to be on this project, it turned into a sub-project all it's own. After successfully putting the new tire on, keeping the same perfectly-good innertube, and adding the Slime protective strip between the tube and the new tire's tread, I installed it on the bike and left it on the test stand.

The test stand is just a pair of Mac Plus cases (without any computer/etc in them) I put under the cargo pods to hold the bike completely off the ground, kickstand and all, to make it easier to work on the back end and to run motor and drivetrain tests, which I can't readily do with the kickstand down (it interferes with the chainline when down, but not when stowed). So there was no pressure on the tire other than the 50PSI I keep them aired up at.

Not long after I put it up there, I heard a hiss, then a quick rush of air. Upon taking the wheel and tire back off, I found a very large split (about 3/16" long) in the *inner* side of the tube, nowhere near a seam or anything else. I VERY carefully inspected the whole tire, rim, etc., just to be sure I had not missed a sharp edge or thorn on my first pre-install inspection. Nothing there, visible or tactile. The 3/4" wide spoke-cover strip was installed correctly, covering the spoke tensioners, no issues I could find. I even rechecked my tire-installing tools, which are heavy-duty plastic with very smooth ends, and found no damage or anything else to explain it.

Must be rotting rubber (remember, the tires were sunrotted), I guess. Digging around I found two other 24" tubes I could use, a couple of 20" that wouldn't by any stretch of themselves or the imagination fit on the 24" rim, and a small pile of assorted 26" tubes, including a new-in-box Slime Thorn Resistant tube I used to carry on the upright bike as a spare, until I'd gone a whole *year* without a flat.

These are the three 24" tubes I was working with.

The yellow patches were added by me, as were a few black ones you can't readily see (some made from other unrepairable totally-blown-out tubes, such as the batch of them I had more than a year ago that had valve stem failures). One patch on the right outer part of the rightmost tube, with a reddish outline, was already on that tube when I got it.

What was most frustrating about this is that the original tube had not had any problems before this, and that since the hole was on the *inner* edge, the slime could not seal the hole! I patched it but reinflating it found yet another hole, and holding a finger on that, another, and another, most of these on the sidewall or inner edge, really making me question if the tire tool was doing this (since the new tire seems to have a much tighter bead than the previous one, and is much harder to get on and off the rim).

However, the same was true of the other tubes, which I tested before even attempting install; I inflated the first and heard it hissing right away, without even 30PSI in there. The leak was on the inner edge. I patched it and tried again, only to find another and so on and so on. No inner-edge leak on the last one, so I tried it out, and only had to patch one other place on it besides the existing patch. Now I theoretically had a tube to try out.

Installed, tested, ok. Put on the bike, ok. Bike off-stand, resting on tire, ok. Rode around the block a few times, ok. I had the batteries and motor off the bike for the motor repair at the time, so it was lighter than usual by a lot. At this point, I was getting tired and frustrated, and hot at maybe 2pm or so, so I went to the store for some fake Dr. Pepper; in this case Safeway's brand of Dr. Skipper, as it was closer than any other store and they had a sale I could almost afford a 2-liter of, for 89 cents I think.

Almost halfway there, about 1/4 mile, and PSSSSSSHHHHhhhhh the tube pops. Ugh. I decided to walk it home and fix the tube first, so I wouldn't trash the tire I just put on there.

Another hole, about halfway around the outside part between the old patch and the new one. I gave up on it and started thinking about the 26" tubes.

Finally I decided that I could fold up the extra bit of tube in two places at opposite sides of the wheel, 90° either side of the stem and reflector.

That's not the tube itself, as its' in the tire and I don't want to unravel the other NIB one I used for the pic above, either. (they never go back in the box, do they?)

But basically like that, stuffed into the 24" tire, with the Slime protector strip around it. I inflated it a little bit, then bounced it till it stopped creaking and shifting inside, then fully inflated it, installed the wheel, and test rode around the block a while.

When I felt safe enough, I went after that soda with no problems.

Now, one thing I do figure is that the slime inside the tube wouldn't be able to circulate freely, due to the folds, so I used an extra dose of slime in it before folding it:

This is the chunky slime, meant for tubeless tires, and it will seal a much larger hole than the regular stuff, in theory. Works so far in my other tires on other bikes, and for a couple hundred miles on this one (until this tube problem).

I just had to squeeze it around in the tube till about half of it felt like it was in each half of the tube, fold and install.

I did a few other things before heading out to the Phirst Phriday ride downtown (about 10 miles away from my house), which included changing the chainring on the motor from a 24-tooth to a 21-tooth, while leaving the crankshaft end of that chain at 24-tooth.

This means that now the 120RPM of the motor at full speed, which currently turns the crankshaft at 120RPM as well, and thus is about 1/3 higher speed than what I would pedal at normally (90RPM), would be roughly 105RPM now. Pedalling along with the motor's full speed would now be much easier, without feet being knocked off of the pedals by any sudden burst of speed (caused by a slight downhill grade, for instance, like going out of a driveway, etc.). Also gives more torque to the motor for startup from a stop.

This chainring is of course smaller diameter, which means it will not be able to bolt directly to the face of the hub on the motor, or else the chain won't engage the teeth. I used a stack of washers on each of 4 bolts to keep it just far enough away from the hub to let the chain fully ride on the ring and not touch the hub. The hub itself had to be flipped over and then spaced a little away from the motor, so it would still line up with the chainring on the drivetrain crankshaft, and not rub on the next chainring there.

None of that would be much of an issue, except that since it *is* a smaller diameter, it also can't use bolts the size of the ones holding the other chainring on, and actually must be pretty small due to the tiny 3/16" overlap of the holes in the chainring vs the holes in the hub. I knew that this arrangement couldn't sustain resistance against the torque needed to drive the bike from the motor, even with my pedalling, but I didnt' really have any idea how long it would last.

I set it up, tightened the chain tension, and tested it just on the stand. No problems free-running. I setup a friction grip (leather welding glove) for the rear wheel, and put as much strain in jerky and smooth ways as I could on it, and still it held fine. Rode it around the block a few times, and still fine. Guess it was better than I thought, as I didnt' see any wear on the bolts yet.

Well, it did last a while--almost 5 miles. Then as I was riding south in the bike lane on 15th Avenue, I heard what sounded like a bucket of coins on the road, and suddenly had no motor assist, so I stopped. The sound was the washers spilling off the bolts, which had finally been cut thru by the hub vs chainring torque. Since I was expecting failure, I'd brought the tools and old chainring and bolts with me, and changed them out, setting off again after about 20 minutes or so.

My next failure on the way there was completely unexpected. The bottom wheel on the rear derailer just fell off.

The roller pin it's bolted in with had somehow unscrewed itself (I still can't figure out how), and the roller wheel was just yanked right out with the pull of the chain vs the springs in the derailer tensioner. I was still pedalling at that point, trying to figure out what the noise had been, but couldn't stop due to traffic, as I was coming up on a green traffic light and the bike lane had ended for the right-turners to get to the edge of the road, so I kept going thru the intersection and then found I couldn't shift up or down.

I braked to a stop and got off, looking at things, thinking a cable might've broken (but it didn't feel like that, it felt jammed), then I saw the derailer's empty bottom spot, and my jaw dropped.

I left the bike on the sidewalk with it's lights on, key pulled from the motor switch, on it's kickstand (no one is running off with *this* bike that fast without motor assist!), bike lock around the wheels and frame, and walked back along the path to see if I could find the roller. I did, but not the center-spacer or one of the two side washers.

Great. Halfway from nowhere to home, and I've got a two-speed bike. :(

But wait--I have a SPARE DERAILER!

Well, sort off. It's a Suntour, not a Shimano, so of course the parts don't match well enough to just put the unused bottom roller wheel's washer and center spacer on the Shimano, but the whole wheel, washers, and spacer did fit, being a tad larger in center-hole size than the Shimano.

Wow. I'm really glad I didn't actually take the derailer off of that chainline now, and instead just left it as the tensioner, even though it isn't the best way to do that. :-)

It'll hopefully never happen again, so now I should be safe to replace the derailer-tensioner with a purpose-built one with my throttle in it. :)

After seeing a few of the bikes on the FreakBike Nation forums, I think I might scrap my idea of a box with all the throttle stuff in it, and instead just use a brake-arm with the roller mounted on the end where the bolt would have been to hold the cable tight, and the pivot point one of the brake-studs welded onto the frame along the chainline somewhere. It's simpler, and the parts are already pre-made for torque in those directions.

The Phirst Phriday ride itself was interesting, though I found the bar-hopping part of it at the bars themselves not fun, as I'm not really a bar-type person. I did like the gallery we stopped at, and I really liked the riding around in a group, and talking with the few members I managed to for any length of time. Wished I'd been able to talk with more people, but I'm still new to them, and they already have friends and people they know in the group, so it'll take a while before I can really become part of their conversations. I'm also not a very good in-person person; I do much better via text formats, like blogs, forums, and emails. Gives me more time to think about what is being said, and what I'm going to say, so I don't sound quite so much like an idiot. :-)

The Crazybike2 was a pretty big hit, apparently--it's not quite like any of the other freakbikes there. Lots of people interested in it, at least in passing. The lighting was an oft-touched on topic, as was the reuse and repurposing of so many odd components.

A pic by Stephon from the forum, from outside the first bar:

I liked quite a few of the other bikes I saw there, and some of them gave me specific ideas I will have to use myself eventually. One in particular that I liked was the black delta trike by "lostideas" with the airtank seat and airshocks on the front fork, which can even be bounced up in the air. Even has a rack for a big jambox on the back. It's too small a trike for my own purposes (hauling cargo, etc.), but it's definitely interesting, and I will likely research more on it's design when making my own.

The chopper-style ones had interesting points, but I really wouldn't want to ride one. :) Looked cool, but not my style.

One thing that I have seen on several bikes there and on the forums is a front shock arrangement that does not use the "shock absorber tube" style of fork that is common to all the MTB designs I've seen, and the roadbike I have now (and the fork I am using on the Crazybike). Instead they use a double fork--the bottom fork appears to be the load-bearing/steering fork, while the upper fork ties a pivot point on the dropouts to a shock-mounting plate near the headstock, with various kinds of shocks between that plate and the headstock swivel hardware. I never even imagined such an arrangement before, even though the idea itself appears quite simple, and I can't see why I didn't think of that. It's like not being able to figure out how to open a pop-top soda can, or something! :-(

Now I know how I will revise the look of my curvy version of the Crazybike2 frame, the one a couple dozen posts or so back, with the leaf-spring rear shock. Maybe I'll do a leaf spring shock front *and* rear. :-)

The ride home around midnight was nice, and very uneventful. The batteries lasted the whole way home, though they were pretty well dead by the time I got to my house. Since I hadn't charged them at all at or during the event, after having ridden the 10 miles or so to get there, plus at least a couple of miles or so during the event, I'd say that's a pretty good range, of about 22 miles. I'm sure if they were new batteries, and I had the bugs worked out of the drivetrain and throttle control, making it more efficient, I'd get a lot more than that.

Now I've got about a hundred miles on the motor/battery setup since first install, well over two hundred miles on the bike as a whole. Still working very well considering it's literally a ridable pile of junk. :-)

I rode up Central Ave, right thru downtown Phoenix, with barely a motor vehicle in sight, and more than a few other cyclists, in groups and alone, usually on sidewalks rather than the road, mostly without any helmets, lights, or other gear, dinging their bells when they saw me riding by. I didn't have a bell to ding back, just my car horn, which didnt' seem appropriate to use in response.

I think I will have to finish that teletype-bell idea I was working on a couple of months ago but gave up on after realizing no car would pay attention to it, if they could even hear it. Since I ride only on the road, and bells are more commonly used to warn pedestrians or other cyclists of a cyclists approach, I didnt' see the need for one until now. It would be useful for responding to other bells in a friendly fashion, though.

If there are future gatherings, I'll go if I am not working, and they're close enough to bike to.

No comments:

Post a Comment

Alternate suggestions or improvements to anything that's been posted is very welcome, and extreme detail is preferred to brevity.

Keep in mind that unless you leave an email address in your comment, I haven't any way to reply to you except to reply to your comment here. That means if you want a reply, you'll have to come back to *this* blog entry and it's comments to see my reply to you, unless you leave some method of contact within your comment.