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Wednesday, November 14, 2007

Blowout from hell

Today, I thought it was time I trued the rims on the bike, since they've been fairly wobbly, with too much space having to be left for the brake pads to not scrape on the rims when not braking, etc. That took a while, since I've never done it before, and I dont' have a truing stand, so had to settle for the on-bike method, which is not as good. Now they're straight, with less than a millimeter of rim side-to-side wobble.

I can't fix the radial wobble yet, since a large part of it appears to be the tire itself, even without the tube in it. Perhaps up to 3 or 4 millimeters radial wobble, which is likely being damped by the pneumatic action of the tube/tire in actual use, but is taking energy out of my forward motion that I'd like to keep.

I wouldn't have messed with the wheels at all, if it weren't for having to replace the tube in the rear wheel, though. During my last overnight shift Monday night/Tuesday morning (till after 4am), the bike was "safe" in the warehouse of the locked building that all of us were inside, 3 regular workers including the store manager, plus maybe a dozen or so outside workers brought in to help with the stock reset. It was fine until sometime after midnight or maybe 1am, which was the last time I actually was at the bike, getting some snacks out of it's cargo container for a break. When it came time to go home, I wheeled the bike up to the front and noticed it dragged, and that the rear wheel was flat. Didn't think much of it, because often thorn flats would leak fast until the slime plugs them up, which can take a few air-ups, but usually last long enough to get me home.

The situation with people I didn't know waiting out front was a little wierd, so I deicded to ride a bit away first, to a well-lit area in clear view of a BofA's cameras, and an intersection with at least some traffic (it was after 4am, so it was starting to pickup a bit). I took out the pump to air it up, and discovered it didnt' have a stem--it had been completely cut off! Looks like a box knife cut. Can't have been the rim cutting it during my ride, because I have silicone around the valve stem partly to hold it in place, and partly to prevent nicks and such--I checked the silicone today, and it's intact. Even if it wasn't, I filed the rim edge smooth and round around the stem hole long ago, since it needed deburring when I got it. Someone didn't want me to get home that night, and I am pretty sure it was one of the outside workers, and I think I know which one it might be--a creepy guy that was asking where I lived (which I didn't answer with anything useful).

Except that I had to ride all the way home on a flat tire, with slime making the rim slide around on the tire's bead so I had no traction, nothing happened; it just took me a bit longer to get home, and I was worried the whole way that either the rim might break (it was undamaged, thankfully), or someone might see my trouble and help themselves to me as a victim--something I never want to go thru again, having been mugged once back in 2003 was quite enough.

That, however, wasn't the blowout. *That* happened tonite, about 20 minutes ago. I'd replaced the tire and tube with new ones, slimed the tube, and aired up the new tube hours ago, and left the bike in it's usual spot in the front room near my door. then 20 minutes ago, I heard what sounded like frying eggs, then a whistle, which all freaked the dog out. I got up, then as soon as I got to the door I could tell it was coming from the bike--turned on the light and saw it was almost flat on the rear!

Closer look shows the tube blew inside (can't tell where yet, gotta take it off the bike and wash slime off of it). But I am flabbergasted that a brand new tube blew at 60PSI without any load or ride, with a new tire around it that I had checked for sharpies or defects. The rim itself I have coated with silicone inside, to help stop air leaks around the spokes and such, as well as protect against sharp edges, plus the spoke belt normally there. So there ought to be nothing to cause something like this even during a ride, much less just sitting there! Heck, the air temperature in the room is probably 10 or 15 degrees lower than when I aired up the tire, so the PSI would actually have been *less* than 60, and the tire is rated for 65PSI. The tube does not list a rating, but being a thickwall anti-thorn tube, constrained by the tire, I would not have expected any kind of problem at these pressures with no load.

I guess I'll just have to air up all my spare tubes to see if they're gonna do the same thing, *before* I have to ride them. What sucks is that I don't have time to do this before leaving town for a few days, and I will probably have to work the very next day once I'm back in town (won't know till next week, because their schedule isn't made yet, so far never till Friday and sometimes not till Saturday or even Sunday the week of!). So I will probably lose much sleep time when I get back to testing and fixing the tube problem, so the bike will be rideable for work the next day.

I have been looking at airless tires for a while now, and I tell you that if I had the money, I'd buy a set just to keep from dealing with this problem at the last minute all the time for workdays--I've had three tubes from different makers and different stores, in two different rims, which blew around the stem itself, either at the base of the stem where it joins the tube, or at the top where the brass stem and valve are joined to the rubber stem. I've had over a dozen tubes blow along seams leaving holes too large to be patched. Probably 8 or 9 that were repeatedly patched for thorns until they blew somewhere else or tore from too many holes in one area.

Another one was destroyed by a roofing nail that went right thru the Slime-brand teflon strip that's supposed to be nail-proof. Yeah, right. I guess their slime sealant works well enough as a temporary seal, but those strips are useless. Maybe they could stop thorns, but certainly not a nail, despite their pictorial advertising that it will do so (they show screws, nails, thorns, glass shards, etc, all stopped by the thing--the nail went right thru the strip, leaving a bigger hole in *it* than in the tire!). "Slime Tube Protectors" product page.

I just wish companies didn't make such junk, and instead made well-designed, well-manufactured products designed to last. Instead, it's all made in China, by slaves that don't care (and I don't blame them), and there's no consistency in any of what's manufactured. Certainly msot things don't meet advertised claims, and are very very far from ever meeting customer expectations.

I don't expect miracles, but I'd like to at the very least have tubes that don't blow by themselves with no load, at nominal pressures (way less than max), when the bike is just sitting in my living room.

Update: see my new Slime post up above this one. This is actually one *good* company that holds to their guarantees! So while I still hold many companies in contempt, Slime isn't one of them. I'll freely continue to spread the good word on their products. I'm not removing what I posted in this entry, because it was still true for me at the time I wrote it.

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