Semi-Recumbent Recycled-Parts Cargo eBike: "CrazyBike2"

[amberwolf]

Guess what?

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At least it was a "slow" leak, keeping rideable pressure for about 1/4 mile, so I only had to stop 8 or 9 times on the way to work to re-air it up. I began to feel it just as I was heading out of my side street to 29th Drive, sort of a wallowing, and I had no time to try to stop and fix the leak, only to keep adding air when it got unrideable (around 10-15PSI).

Same thing on the way home from work. Although this part wasnt' really time-critical, I didn't feel like sitting in the dark taking the bike apart to deal with it, so I just rode home with frequent stops.


It was frustrating, because not only do I have the slime tire liner, I also have a cut-open-on-it's-inner-circumference nice thick tube as a secondary liner including for the sidewalls, and then chunky slime in the tube itself. So, basically there should be very little that gets thru in the first place, and if it does get thru it ought to be plugged up quick.

But this didnt' fail in any place that could be helped by any of that--it was in the valve stem, AGAIN:

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I carefully examined the rim's valve hole and found no irregularities or sharp edges, and the crack in the stem doesn't line up with either the inner or outer rim layers anyway. So I guess it's just one more in the long line of valve stem failures from poor manufacturing that I have had over the last several years.



I am SICK and TIRED (haha) of flats. So I decided to make myself a Twinnertube, as others have done before:

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I drilled a second valve hole in the rim, 180 degrees from the original. Then I went thru my four remaining mostly-usable innertubes, and found one with no patches yet, and one with only one, and both held air fine the whole time I had them stored in the wheel closet, since the previous flat problem a couple weeks ago, I think it was. There were actually seven tubes put away then, but one of those also had a failed valve stem, and two others simply had so many little holes that I don't have any way to patch them all.

So I took two of the four remainign ones, and installed them in the tire/slimeliner/tubeliner previously on the bike, and then onto the rim. I'll tel you--if you think getting a single tube and tight bead tire onto a rim is tough, doing it with what amounts to three tubes (the tubeliners and two actual tubes) in there is danged near impossible. Took perhaps 45 minutes to get the tire on there without damaging either tube.

Then I aired each up a little, 20-30PSI, let it all out, reaired, let it out, etc., to help them seat against each other. When I could feel/hear no more shuffling or "creaking" inside, as the tubes moved during air-up, I filled each about 30PSI for a total of 60PSI, and mounted it back on the bike.

This means that assuming there isn't any rubbing between them or the tubeliner or rim, and nothing wears thru, then when eventually one of these two fails suddenly and catastrophically, the other tube still has pressure in it, so I don't lose control, etc. Even if it's just a regular failure, slow leak, etc., I still have the other tube to keep me going, and if I need to I can just air that tube up to full pressure.

This is just theory, though, siince I've never tried this before. I hope I never get to test it.


While putting the wheel back on teh bike, I noticed that the rim is pretty deeply dented at one point. Basically a big flat spot. I can't true it out, either, so I'll just have to live with it.



Thankfully, I had the electric air pump with me since the last failure, as it would've been a lot of time and energy to handpump the tire on the way to work and back home. Possibly more than I could handle. I forgot to post it previously, but I took the Anderson-connector wires off of the old 12V NiMH lighting pack, and put it on the compressor. That way I can hook it up to my 12V pack on the bike, and if necessary also keep the ligths running. This was very handy today, and saved quite a bit of time.

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The wiring barely fits in it's little case opening.

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[texaspyro]

I hope I never get to test it.

Oh, you will. Yep, you certainly will. Something tells me it will fail. Sir Edsel Murphy seems to have the hots for you.

[amberwolf]

Well, it hasn't failed per-se yet, but it was low on my way home today. Maybe 40PSI? Aired it up and it was ok still when I got home, 2.5 miles of ride.

One problem I did have is that I didn't mount the wheel perfectly straight, so it rubs a teensy bit on the tire knobbies on the left chainstay, at that part of the rim that's bent / flatted inward in that video above, as the rim is also bent slightly leftward there, too--just enough that I can't fix it with spoke tension. So tomorrow before work, or tonight if I don't fall asleep first, I have to loosen the dropouts and axle nuts, then straighten the wheel. I was in a hurry when i put the wheel back on after fixing the flat above, and didn't check for rubbing, just basic alignment, and I also didn't test ride it, which I should have.


Anyway, we'll see if the tire is low again tomorrow before work, and if it is, I'll know there is a problem in one or both tubes, which will suck if true--they were perfectly fine before going into the wheel.


Oh, also, I thought I had fixed the turn signal switch, but the glue apparently doesn't work properly on whatever type of plastic that is. Normally it works on everythign except polyethylene (PE or HDPE), and actively dissolves it, so that the bond is plastic intermixed, and very strong. But the switch came off again today on the way to work, fortunately I had not yet taken the rubber band off (kept forgetting to), so I didn't lose the switch. I guess I'll have to drill it and put a pin in both peices.

[JohnC]

AW, Have you thought about going “ghetto” tubeless?
Home brew tire sealant: 50/50 Green nonpremix glycol (antifreeze) + Alumaseal radiator sealant (liquid version)

[amberwolf]

Now that could be useful...as long as I can still re-air it up on-road using the little portable no-tank compressor I've got, but it doesn't put out air very fast so it may not work for that. I do also have two little CO2 canisters with the adapter for Schrader in the kit that came in the seatbag on the Nishiki, but I don't know if they're sufficient for the tire on CB2. I could probably rig something up with one of the various CO2 bottles I have around for paintball, to make an adapter to Schrader for those.

At home I can just use my regular big compressor, but I would need a definite way to reair it while on-road, especially while loaded up with cargo.

I suppose my biggest potential issue is the stupid valve stems: It doesn't seem to matter what kind of tubes I use, I still have issues with them just splitting open, someitmes actually ejecting the whole brass stem!

One possibility is using a valve stem off a car tire rim, and forcing it to seal into the inner rim hole of the doublewall rim on my motor wheel. I would need to work out a different inner liner method than his, but I could simply cut out a regular bike tube's valve stem, and glue it to the car tire's stem, then force the stem down into the valve hole, and let the pressure of that keep the two together, with lots of rubber cement around the inside of the valve stem/tube connection to guarantee seal.

I already have some 50/50 antifreeze in the shed from back when I still had to maintain my mom's car. No alumaseal, but I think a friend has some I can use.

Either way, it would certainly make the wheel a bit lighter. Then I just need some moped tires to make them tougher. (rims, too, if I can ever find someone tossing an old moped out).

More stuff to ponder....

[amberwolf]

Well, Murphy is tagging along closely: I just did a grocery run, and just before I left, I checked the tire, down to about 20PSI by the compressor gauge. So one or both tubes is leaking a lot.

I reaired them to a total of 50PSI, went for the groceries, and came home, and it's at 45PSI.

I'm going to test by deairing one tube completely, then airing just the other, and seeing if I lose air, and how much. Then do the other tube. That'll at least tell me which tube is losing air faster.

Either way, it sucks.


I would like to take the wheel off, and take the tire off to examine the tubes for folds, wear marks, etc., and test them with soapy water for leaks, but I don't have another day off till Friday, and not nearly enough time today before going in for my half-day of work today. So I guess Friday I'm going to do that, unless somethign dramatically fails before then and forces me to do it earlier.


Ugh. Oh, well, that's the thing about experiments: they don't always work!

[ddk]

never had much luck with the slime tubes
I'm currently using the Bell version of the slime tubes but I haven't put on enough miles to tell.
After using (expensive) tire liners that failed I went for the "make the tire easy to change the tube" route.

On a delta trike, this seems the most sensible as one can easily change rear tubes without dismounting the wheel from the axle.
I always carry a spare tube, tube patches and a stand-up manual pump (because I can LOL)
like this one, only mine's lighter and a few bucks cheaper (plastic tube -good up to 125 psi)

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[amberwolf]

never had much luck with the slime tubes
I'm currently using the Bell version of the slime tubes but I haven't put on enough miles to tell.
After using (expensive) tire liners that failed I went for the "make the tire easy to change the tube" route.

So far almost all the actual system failures I have had have been something that the slime and liners couldn't stop, because they're on the inner circumference of the tube, or on the valve stem.

All the normal failures were prevented by the liners for tread punctures, and the slime for sidewall stuff if it's not too high up.

The only out-of-bounds failure I had was when my tire completely ripped open in two places on the tread, alllowing the tube to fully push out of the tire and shred. Nothing would have stopped that one, besides changing the tire before that could happen, which I knew needed doing but just couldn't / didnt' get done.

On a delta trike, this seems the most sensible as one can easily change rear tubes without dismounting the wheel from the axle.

That's something I like about the trike wheels, at whcihever end has the pair. But the problem still remains on the other wheel, and that's most likely where I would be encountering the problem, just because of Murphy.

A single-sided swingarm or fork would fix that part, but present other challenges that would likely cause worse failures in my case, as I don't really have the right engineering or materials to do something like that safely without so severely overbuilding it that I think the weight would be too much.

I always carry a spare tube, tube patches and a stand-up manual pump (because I can LOL)
like this one, only mine's lighter and a few bucks cheaper (plastic tube -good up to 125 psi)

air pump.jpg

Yeah, I have all that stuff, (except the spare tube, right now) except mine's now an electric compressor, but the failures have been unpatchable last two times, on the valve stem, and a new tube wouldn't have done anything but shred on the one before that, with the destroyed tire.

I haven't carried a spare tube since moving the motor wheel to the rear and having the tire disintegrate, simply becuase it is such a job to get it off. But I have now got it down to only maybe 10 minutes to get off, and another 10-15 to get back on. Plus another 15-30 to get the tube changed, it's only an hour or so on roadside fixing it. Still, I do now have a spare tube in the toolbox, too, if I have to do it.

Having two tubes already in the tire hopefully will mitigate having to do this, but so far it's not working out so well.


Ideally, what I will have is a heavy enough duty wheel/tire to not have to worrya bout it. Short of that, moving the motor to the frame and using regular easy-to-swap-out bicycle wheels, I can actually carry a full spare wheel on the bike, kind of a "continental kit" sort of thing if I made it fancy.

But with the motor in the wheel, and the failures tending to concentrate there, it's not really practical to carry a whole spare wheel, even if I had one.

[ddk]

In Lincoln, NE there were these thorns I don't remember the name of, shaped like jumping jacks that could pierce about any bicycle tire/liner/tube or combination thereof.
I was always chiding my kids about riding off-road because of those (sometimes found 'on-road' also)
One can only puncture a slimed tire so many times before it cry's "uncle".

My last set of tubes in my 'new' location experienced the same type failures you've been experiencing (around the stems)
-any wheel, any time-
Judicious filing, making the holes slightly larger and smoother seems to have cured that, as it's been a few weeks since my last flatted tire.
Previous to the reshaping exercise I was getting a flat a week (caused mainly by road debris catching the stems)

needless to say I now have lots of tubes for those instances where an otherwise useless bike tube can be re-purposed.

[kevo]

Davis CA has those thorns in the fall. Makes for great business for the local bike shops.

[amberwolf]

In Lincoln, NE there were these thorns I don't remember the name of, shaped like jumping jacks that could pierce about any bicycle tire/liner/tube or combination thereof.

Yes, we have something like htem here, often called bullthorns or bullhead thorns, cuz they kinda look like a bull head with huge horns sometimes. They range from ilttle 1/4" types all the way up to nearly an inch, probably from different types fo teh same plants.

They suck.

Hachi hates them too, because they go right thru the pads of her paw, and stick; she just hops on three legs until she finds me, and holds the afflicted paw up to me with "those eyes"; you know the expression I mean, if you've ever had a dog. Often the sticker already fell out, but she hasn't realized it cuz it still hurts so much (had them in my foot, i agree whole heartedly). I wipe the bottom of the paw with my hand to find/dislodge anything, and then she's ok.

There are areas of teh yard that they end up in from somewhere, that she will not go thru. She'll head right around mcuh of the center of the yard, and just looks at me disgustedly if I throw a toy and it lands there. She sneeze-snorts and sits down, waiting for *me* to go get it instead.

Nana is smart enough to wipe her paw on grass to pull them out, but she doesn't worry about going thru those areas herself--guess it doesn't hurt her as much or something. Loki and Fred never complain so I don't know if they have problems with them or not. Bonnie would usually pull them out with her teeth.


They're not as bad as the mesquite thorns Dogman has to deal with, which can be inches long, like wooden needles.

One can only puncture a slimed tire so many times before it cry's "uncle".

True, but I've never run into that limit--something else always destroys the tube long before then.

Judicious filing, making the holes slightly larger and smoother seems to have cured that, as it's been a few weeks since my last flatted tire.
Previous to the reshaping exercise I was getting a flat a week (caused mainly by road debris catching the stems)

I wish that was the problem, but I have not only long ago usually sanded the holes on the rims I use, I also have tried various types of protective material around the stems, from tape to drinking straws to teflon strips, etc., all to no avail. It isn't something from outside damaging the stems, AFAICT, it's the stems failing from inside--the material itself separates from the brass valve shell, and then tears at the really thin area there. At least once I remember haivng the whole brass section separate and blow out like a bullet, whiel I was in the bedroom sleeping I think, and it scared the crap out of Bonnie (only dog at the time).

needless to say I now have lots of tubes for those instances where an otherwise useless bike tube can be re-purposed.

Yeah, I have at least a dozen or so still-stretchy ones with failures that can't be fixed, saved for whatever purposes might come along.

[amberwolf]

Well, I suspect the tubes are rubbing and causing leakage in each other, because now either tube will deflate over a few hours to less than 20PSI, from about 50-60PSI starting, even with teh other tube left empty.

My next day off isn't till the middle of the week, so that's when i will probably have to take teh wheel off adn find out what is happening inside the tire, as I have not had time to do it yet. As long as the leak is slow enough to last several hours, I'm actually perfectly happy with that, compared to having to air it up several times a mile. I expect it to get worse quickly, so I need to take care of it as soon as possible.


Good news is everything else is still working fine, including the clamping dropouts, the tire, the motor, the freewheel, etc. Even the disc and rim brakes are working well enough--could be better but are almost sufficient. Much better than any other brakes I've used so far. I expect if i had the correct brake levers for them they'd work even better, but I am not sure which levers I have are the right type for these, so I will experiment as I can find different ones, and see which types improve or degrade performance.

The front wheel and fork and whatnot are all working very well. No tire or tube or wheel problems there, especially.

[amberwolf]

Well, two really bad things today:

First, as expected, the tire is worse to the point it doesn't even last the ride home. I guess I have to fix it before I leave for work tomorrow late afternoon.


Second, much worse, I have killed my 12V 3-cell experimental pack. I *ALWAYS* unplug the battery connectors from the system when I leave the bike, but today I apparently forgot that, and someone played with the switches on the handlebars, leaving the turn signal on rightside, and the headlight on highbeam (which is both filaments, something like 6A I think, maybe more).

Since the signals don't automatically blink right now it isn't apparently attention-grabbing enough for anyone to point it out to me, and I was working in the bakc of the store all shift, and thus didn't see it myself.

It probably didnt' evne last an hour after being turned back on before draining down to the cliff point, since I had not recharged it in a couple of days or more (would have been doing that tonite).

Nobody turned on the main power breaker for the traction pack, so it didn't get any drain, but the 12V pack is 0V now.


Now, neither of these things would be a total disaster by themselves, but since my air pump is 12V-powered, and I needed to air up the tire more than once to get home.... Before leaving work I had a coworker help by letting me power the compressor off his car battery for the less-than-a-minute it took to air it up to 50PSI, but then about 3/4 or more of the way home, the tire was down to maybe 10-15PSI based on it feeling pretty squirrely in turns, and probably doing more damage to the tire or tubes than they already have.

By the time I got home, it was pretty much totally flat. Since the tire I have on it now, plus the innertube "liner", plus the two innertubes, is a lot of material compared to the previous thin tire and single tube, it didn't feel like I was riding on teh rim, at least, and I had traction and the tire stayed on the rim, etc.. I'm posting this while I eat somethign, and then rest a bit, then I'll have to take the wheel off and see what's what.



As for the 12V pack, since it isn't straight LiCo, and it's toast otherwise anyway, I decided to try slooooowly recharging it at 100mA current limit, back to 4.0V/cell. So far there is no unusual behavior, and it's up to 6.3V after a half hour. Charging is being done outside on concrete, where the dogs can't get to it, with a metal trashcan sitting over the top of it just in case.

We'll see what happens. Since I won't be able to trust these cells until thoroughly tested, even if they recharge, I'm going to ahve to use the little ex-military-type pack from GMUseless for the 12V lighting power for now, until I get the chance to test out some of the RC LiPo packs for good/bad cells and build up at least a 3s-3p pack for it, preferably 4p.

[amberwolf]

The good news is that the battery hasn't exploded, and was at 9.6V when I unplugged it just before leaving for work today. It hadn't lost any voltage by the time I came home 5 hours later, and in fact had gained nearly 3/4 of a volt. It is now continuing to charge, no visible signs of failure either.


The other good news: there is nothing wrong with either innertube, valve stem, or valve. There are no leaks even in an soapy-water immersion test of the bare tube, even inflated to stretch the tube out quite a lot, far enough I was worried I might burst them. I squeezed and rubbed their entire surfaces including the valve stems while underwater, and no signs of bubbles, or of escaping Slime.

I even left them sit to dry for around an hour, and there was no change in inflation during that time.

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I did manage to break a tire lever for the first time, trying to get the Maxxis knobby tire's bead off the rim, though. Bad because I only have two (since the others, the better ones, were all in the toolkit I lost by leaving it on the sidewalk months ago (has it been a year yet?)). Had to use a wide flatblade screwdriver with rounded edges from much abuse as a prybar to finish getting the tire off and then back on.

The bad news: They still deflated from 50-55PSI total down to 20PSI during the time I was at work.

I'm baffled.

Unless there is a leak in the valve core itself in *both* of them, that only happens when they're pressurized inside the tire, I really don't know where they could be leaking from. I'm gonna stick some different valve cores in there to see if that makes a difference while they sit overnite.

[amberwolf]

So...I fell asleep and forgot to swap out the valve cores, so it sat all night and then all of today unused but aired up to 55PSI. Then earlier tonight I checked the tire and it was still fully aired up, no pressure loss.

I'm definitely baffled.

[amberwolf]

No pressure loss today, either, even after sitting a couple hours now after i got home from work. I'll take it as a good thing, but I'm worried because I don't know why it lost pressure before, even after being taken apart and put back together, but now suddenly doesn't.


So far the slow recharging of the killed lighting pack is going normally. It is up to 11.1V. Early yesterday I decided to more than double the current to 250mA (from 100mA). Once it had gone fine with that all day, I turned it up to 500mA, and it is still workng fine with that. I've still been disconnecting it when I have to leave the house, but it's reached about 12Ah recharged now, of a nominal 20. It is always holding it's voltage after disconnection from charger and meter.

I dunno how well it will still work after the abuse of discharging it to 0V, but we're gonna find out. I'll be putting it in one of my almost-sealable metal boxes (so it can vent gases without exploding the box, if it does fail dramatically), and then run it at various discharge rates. I may first try using the Venom charger to do this, so that I can log the cell voltage response on the computer, though it doesn't use very high discharge rates.

Assuming it survives that, I'll recharge at 1A or more, and then discharge at higher rates, using just a wattmeter to monitor the pack, and whatever good "bench" loads I can come up with, that are at least equal to my lighting rig, which at most would ever draw 10A or less. I'd like to test at much higher loads if I can make one up easy enough for 12V.

So far the cells are staying in balance even when they were at extremely low voltages (0V up to 3V), from my periodic checks during the recharge cycle. They have been within 0.02V of each other each time I check, using the Fluke 77-III.

[Solcar]

I've often wondered about particles getting between the seating surfaces of my valve cores and the stem bodies. I noticed that on car tire valve stems, they leak less with good caps screwed over them. My bike tires might not have as good caps on their inner tubes because they seem to leak down pretty fast with or without them. Needing air once a month is what I mean by pretty fast leakage, though that is slow compared to what was happening to your inner tubes.

[amberwolf]

Have to be careful with valve caps; Iv'e had them actually CAUSE leaks before, from little bits of flashing inside leftover from the molding process. Metal ones don't usually have this problem, and also often have gaskets to help seal better. but I don't usually use valve caps anymore, because when I have a roadside flat, I often forget to put the cap back on and end up losing it. I used to have a bunch of really nice ones, gasketed, with a conically-curved tip that was slotted to let you use it to tighten or remove the valve core, too. Most of those were left accidentally as donations to the roadside gods.


FOr now the leaks seem to have stopped, as it still works today even after a couple trips out this morning, including a grocery run for about 40lbs of stuff, before Jasonf150 stopped by to pickup the old 36V NiMH pack to borrow for a couple weeks or so, till his Cell_man battery comes in. No pressure loss at all, AFAICT.

That battery is now up to 12.2V, with 12.3V as the final goal (4.1V/cell). Still in balance, still no problems charging, no sign of heat or swelling or anything unusual. Charge current has dropped to 0.49A with the voltage rise. Has about 18Ah in it now. Things are going much better than I expected.

[amberwolf]

Leaky tire problem came back today; they were down to 20PSI when I left for work.

I aired them back up to 55PSI, and about halfway to work I heard a hissing for a few seconds, which stopped (slime plugging it up probably), then when I had a chance to pull over and air up again, they were at about 10PSI.


I aired up the main one (original valve hole) and at about 40-ish PSI, air suddenly vented hard from inside, pushing slime out the valve hole. I don't know which tube that came from yet. Then it stopped, and air pressure increased again. So I guess the Slime helped reseal the hole, or something.

I rode another 1/3 of the way to work, and had to stop to add more air, this time in the opposite tube (in the vavle hole I drilled). No hissing, aired up ok to 55, rode on, but I could feel the squishiness before I even reached work. It was pretty well flat by the time I got there.

I had to air up about every 300-400 yards on my way home. It pretty much sucked, but at least I didn't have to do it by hand.

I took the wheel off after getting home and feeding dogs and giving them all their greetings and whatnot, but I was so tired I couldn't do more than that, and sat down to eat and rest while I browsed ES. Now I'm typing up this post, and will probably have to have a nap before I can get up and go take the tire and tubes off the wheel to see just what the heck is going on in there.


Over the last few days, anticipating more problems, I patched some more innertubes, including the most recent valve-stem rupture. I don't expect the stem patch to hold, but I figured it is worth trying, as if it does work, I might be able to fix a couple of other nice tubes that failed only at the stem.

Most likely I am just going to take both current tubes out, replacing with two patched ones, including that stem-patch to test it.

Then we'll see how things go over the next few days. I hope well, because my next day off isn't till Friday, and I have at least one day that I must close and then open again the next day, with less than 12 hours from when I leave work to having to be back there again. Including time to get home, time to do all the stuff I must do when I get home and then getting ready to leave the next day, that's only about 9 hours or so to eat, sleep, or do anything else, whcih is why I really hate schedules like that. I may not even get any real sleep, just fitful stuff for an hour or two, in bursts of a few minutes at a time--that's typical for nights like that. I definitely wont have time to fix anything on the bike unless it's really dire.

[ddk]

Captain Obvious Here:

I'm gonna have to ask the o-o-o-OBVIOUS question

-are the valves tightly screwed into the valve bodies?

[mdd0127]

I think it would be a good idea to look into some maxxis downhill tubes. I might have given you one at some point.....can't remember. They're extremely thick and even though I ride through fields of goatheads and cacti, I haven't had a flat with one yet. I slime them anyway though. I'll dig through my stuff again to see if I have any more spares.

I'm making good progress on getting the new solar setup installed on my little rv so I might be able to come down soon. Maybe in a week or two. Everything's taking longer that I expect it too but it's moving along at least. Wilbur chewed that cyst off of the back of his leg so now he's got a big gaping hole in it. I took him to the vet and the vet said the stitches would just rip out and sent him home with antibiotics. Hopefully it heals up soon. I'll email you that asr manual tonight. Been so busy I forgot about it!

[amberwolf]

Captain Obvious Here:

I'm gonna have to ask the o-o-o-OBVIOUS question

-are the valves tightly screwed into the valve bodies?

That's a very good thought, but yeah, that's the second thing I checked.

I slept fitfully but tiredly enough that I didn't end up getting up until a couple hours before I had to leave for work today, so I simply pulled both tubes out, and put in a much thinner one I'd patched before and has been sitting since the day I setup the Twinnertube 1.0 system.

I did not put in a second one, as it takes some time to work them both into the tire evenly. I didn't have that kind of time before work, especially if for some reason the first tube I tried didn't work, but thankfully it did. It has held 55PSI form the time I installed it until I just checked a few minutes ago, so a little more than 13 hours now, including my ~5-mile commute today.

I did put a spare tube in the toolbox on the bike, but it is one that had the valve stem leak, and I patched it, but have no idea if it will hold.


I examined the tubes briefly when taking them out, and found a pinky-sized hole in one (the one using the secondary valve hole). That hole is almost lined up 180 from the valve stem, and is on the inside circumference of the tube, so my theory is a "pinch flat" on the primary valve hole with the valve stem of the other tube. I do not think that there is enough room for it to expand into the hole normally, but if the other tube went flat first, it could've allowed the still-full tube to expand very slightly into that hole's edge, and then when I tried to air up the flat one on the primary valve hole, it might've pinched the other one, and then later could've cut thru the tube despite the tape/etc I had around the hole.

What is interesting is that I was able to inflate this tube several times after that point, and it held air for a while, even though I'd've expected the Slime to be unable to reach that part of the tube. But I think because the tubes are side by side, the more-inflated one squishes the less-inflated one so narrow that it lets slime ride up the walls and into leaks even on the inside circumference, allowing it to plug holes up there. I see no way it could've plugged a hole this big if it hadn't been being pinched closed by the valve stem of the other tube, though, so that's another part of why I have the theory above about how it was caused.


I didn't see a hole in the other tube, using the primary valve hole, but I haven't tried to air it up outside of the tire yet. Hopefully I'll have time to investigate the tubes in the next few days.

I think it would be a good idea to look into some maxxis downhill tubes. I might have given you one at some point.....can't remember. They're extremely thick and even though I ride through fields of goatheads and cacti, I haven't had a flat with one yet. I slime them anyway though. I'll dig through my stuff again to see if I have any more spares.

I don't think I got any tubes from you, but the tire I'm using probably did come from you, as well as the one I'd like to use but has knobbies that make it too wide for my frame. I don't rmemeber any tubes in any of the tires. (except for the two mongoose basher wheels, but IIRC those were normal tubes, possibly even originals).


The thickness of the tube itself I'm not so worried about, but more the quality of the bond between the brass valve stem core-holder, and the rubber of the valve stem part of the tire. That is where I am getting too many failures, unrelated to the rim's hole (not caused by wearing or cutting, it's just a rupture from within the tube, or in some cases complete separation of rubber from brass!).

Mold-line separation is the other place I have had repeated problems, where the tube casing simply splits right along one of the molding lines, usually on the inner circumference where they tend to be thinner.

I generally don't get "normal" flats, as the tire liners and such tend to keep the gnarly road debris stuff out of the tubes, but I sure do get some doozies from all the abnormal sources.

I was looking around and saw that even Michelin offers some DH tubes; and that DH tubes in general don't seem much more expensive than crappy standard or even walmart tubes would be (8-20 bucks, vs. 4-15 bucks), at least online. Might be different at an LBS, so I will have to call around and see. If DH tubes have better valve stem bonds, and are rated for at least 70-100PSI or more, then I am willing to go out and buy at least one to test with.

Any recommendations for good DH brands regarding valve stems specifically would be helpful. I doubt MadRhino follows this thread, but if he does, I'd like to hear his opinion, too.

I'm making good progress on getting the new solar setup installed on my little rv so I might be able to come down soon. Maybe in a week or two. Everything's taking longer that I expect it too but it's moving along at least. Wilbur chewed that cyst off of the back of his leg so now he's got a big gaping hole in it. I took him to the vet and the vet said the stitches would just rip out and sent him home with antibiotics. Hopefully it heals up soon. I'll email you that asr manual tonight. Been so busy I forgot about it!

Poor Wilbur...Bonnie used to do the same kind of thing when she had owies, as did another dog I had a couple of decades or more ago, who got them alot because he was so alllergic to various things that he chewed holes in himself a lot. I'd usually just smear people-antibiotic cream on the owie, then wrap a bandage around it. Then I'd soak another bandage in water and cayenne pepper, and wrap that around the first one after it dried. He pretty much didn't pick at those. Another dog I'd had long before that didn't care what I put on them, she'd eat any bandage I put on her. At one point when she really hurt her leg, I had to make a little metal "cast" for it that I bolted togehter around the leg to keep her from licking it till it wore thru to some major blood vessel. She was kind of a neurotic dumb dog, that was pretty smart in some ways.


No hurry on anything; life is always a mixed bag of fast and slow and hurry-up-and-wait.

The ASR88 is still sitting on the table awaiting time enough to poke at it's guts again, to see if I can hand-wire across all the corroded traces and thru-holes, once I figure out where they go. Hopefully that will bring it back to life, instead of having to buy a new or repaired board.


Also, I forgot to get your static mat/strap and your Meanwell back to you when you were here last. Remind me about those when you are here next!

[Alan B]

Are the tubes with fully threaded metal stems better?

[amberwolf]

I don't know; the schrader ones I have had always look like the pics in recent posts, with a rubber tube from within the tube's shell up to the threaded part of the stem, and a brass hollow core inside that rubber tube, with internal threads for the valve core.

I *have* had a couple of Presta tubes, with fully-metal stems, bought because there weren't any schrader ones in the size I needed, and I was out and about with no other way home, thanks to yet another blown valve stem, back when I was riding DayGlo Avenger as just a pedal bike, before I started motorizing things. I don't recall a valve or stem problem with those, so maybe that would make a difference.

Are there specific brands that use all-metal stems?

If so, how do they setup the interface between the stem and the tube casing? That interface is what fails in each of the cases I have had so far.

[Alan B]

The schrader stems I have that are fully metal are Schwalbe. They have a nut to hold the stem in place which makes airing them up easier.

Looks like my moped tubes are metal also, those are kenda. Looks like a particular style.