The plot thickens

"HammerheadFistpunch" (hammerheadfistpunch) 05/18/2015 at 23:04 • Filed to: Bike life

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So a little while ago I posted about how I discovered my mountain bike rim, hanging from my ceiling since last fall, had exploded. At first I blamed myself, but as I looked closer I noticed that the failure was an impact from the side as I had imagined....nope, it exploded from the center.

The “smoking gun” was a piece of rim I found that was from the missing side and it was bent OUT with no signs of external trauma.

The rim...literally...exploded from inside. I have my theories but the fact that its right near the hoop seam looks like it just pulled apart slowely until it fatigued and the 100+ KgF of the spoke pulled through an ever expanding oval shaped spoke hole. OR the material was bad to start, which it looks. Either way...glad I wasn’t riding and it looks like its back to wheel building mode for me.

MLGCarGuy > HammerheadFistpunch 05/18/2015 at 23:07

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Idiot. Everyone knows that using a digital tire pressure gauge could have prevented this. Just 1.5 psi lower and this wouldn’t have happened.

HammerheadFistpunch > MLGCarGuy 05/18/2015 at 23:07

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The irony, of course, is that they were flat when it happened. I know because they weren’t holding air at the end of the season.

MLGCarGuy > HammerheadFistpunch 05/18/2015 at 23:10

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I don’t want to be racist but this sounds like quality only China could produce.

HammerheadFistpunch > MLGCarGuy 05/18/2015 at 23:11

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WTB is a top tier brand, but I can’t say that they DONT outsource to china. This was a few years ago when all the outdoor companies were doing it and BEFORE they realized that they had to keep a close eye on QC by keeping a man there.

TwinCharged - Is Now UK Opponaut > HammerheadFistpunch 05/18/2015 at 23:15

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It’s entirely possible. An race engineer I once met before told me about the quality control issues that Cosworth had whenever they outsourced any components to the Chinese. Generally Cosworth products are top-notch solid but whenever a component like a camshaft fails it’s usually a China-built product.

TheOnelectronic > HammerheadFistpunch 05/18/2015 at 23:29

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KgF? The hell kind of unit is that? Kilogram-feet?

HammerheadFistpunch > TheOnelectronic 05/18/2015 at 23:30

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Kg force, its tabled that way on my tensiometer, so I use it.

Frank Grimes > HammerheadFistpunch 05/18/2015 at 23:39

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thats really wierd. at least it didnt happen when you were riding and nothing to prevent sharpnel in the nuts except for some sheer spandex pants.

TheOnelectronic > HammerheadFistpunch 05/18/2015 at 23:45

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That makes more sense.

I’ve seen plenty of mixed units before, I was just hoping they hadn’t spread further.

RallyWrench > HammerheadFistpunch 05/19/2015 at 00:43

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Wow, that’s unusual! What model WTB? I’ve only had 1 wheel start to come apart at the seam, an old Syncros that I rode well past it’s life expectancy.

HammerheadFistpunch > RallyWrench 05/19/2015 at 01:09

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Frequency i19 team. Ive built and worked ALOT of wheels in my day...this was a first for me

Highlander-Datsuns are Forever > HammerheadFistpunch 05/20/2015 at 19:22

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That is totally fucked up, never ever seen that kind of failure. If you seriously over tensioned the spoke, the nipple or the spoke would break. I have never seen a wheel explode like that and I have ruined countless wheels. Usual rim failures are longitudinal cracks along the rim radiating out from the nipple hole, and they give you lots of warning before they crack all the way.

HammerheadFistpunch > Highlander-Datsuns are Forever 05/20/2015 at 19:34

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I’ve been wrenching on bikes for nearly two decades and this one was a first for me. the spoke was propeprly tensioned, it was balanced using it calibrated tensiometer

Highlander-Datsuns are Forever > HammerheadFistpunch 05/20/2015 at 20:42

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looks like you have a DT hub so you could do a rebuild with a Stans Arch or Crest rim.

HammerheadFistpunch > Highlander-Datsuns are Forever 05/20/2015 at 20:47

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Ironically, this was the rebuild. New spokes, nipples and rim for both wheels. the factory wheels had a hub defect in front that broke at the flange...bad luck with these wheels i guess

Highlander-Datsuns are Forever > HammerheadFistpunch 05/20/2015 at 21:01

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My best luck with hubs are Chris King or Shimano, I know King is expensive but you can hand them down to your great grand children after a drip of lube on the free hub.

HammerheadFistpunch > Highlander-Datsuns are Forever 05/20/2015 at 21:03

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I have 240s on my other bike and they are timeless. These were their branded hub built offshore and have shown it