Wednesday, December 10, 2008

23 Bizarre H Plus Son Rim Failure In Japan

Our friend from Japan was gleefully skidding on his track bike with what seems like a black, SL42 anodized deep section rear wheel from H Plus Son. Then he heard the explosion. Kaboooom! Damn, I need my props. Like KABOOOOOOOOOOOM!

A friend of his noted on his blog :

"Last night, we rode bikes and had tons of fun. But when he was doing skid, I heard big explosion I've never heard. Then, the rim has bursted. Inside of rim has collapsed and tube was bursted. But tire has not bursted. Rim was just only two weeks used. It's almost new."

It looks like he had a Latex tube on

If you study these pictures closely, you'll notice that the rim blew apart right across the centerline. I have not seen a failure like this before. Its almost as if it traced a prior crack or a groove along the bed of the rim. The data we have about the size of tire that was used, along with tire pressure are not available from the user or his friend, so I won't unnecessarily take a stab at why this happened. More pictures of the failure on his Flickr page here.

The Wheel And Cross Section. More rim specific information here.

The folks at RBT are discussing this failure in more detail, along with the usual digress. Some are alluding to excessive side hoop forces while skidding, while others are theorizing at heating of an overpressurized tube and subsequent bursting causing rim failure, all during the momentary skidding. I highly doubt that scenario but what else can you expect from a debate?


  1. Anonymous6:55 PM

    I respect people who ride fixed gears. bUT cant understand why they trash their bikes like this? tHESE idiots belong to the circus.

  2. Anonymous7:02 PM

    very interesting. im really looking forward for explanations.

  3. I can sum it up for you, Ron...
    The kid had too many useless cards in the spokes. Combine the weight (w) and the stupidity (s) of the cards, with the asinine-skidding or simply being and ass (a) and you get

    w+s(a)=Carbon fiber go boom!

    I can't feel bad... bikes weren't made to do stuff like that.

  4. Anonymous12:27 AM

    Thats a gaping vagina of a failure!

  5. You're about two weeks late into this discussion.

    Concentrating on the rim makes you miss the big picture. Look at the people and the bikes surrounding this split rim. The rim blew up in what we call a "hipster fixed gear trick session." It is most likely that the rim was abused way beyond the intended use before the skid that allegedly split the rim.

    My guess is that the rider damaged the rim (metal fatigue) by bunny hopping and riding down staircases and it finally blew up during a simple skid.

  6. Yup, this is chilled news. My news is always chilled. :)

  7. Anonymous9:13 AM

    Wonder when this will be picked up by BSNYC.

  8. Anonymous11:43 AM

    Interesting wheel section profile. This seems like a just released product from the company.

  9. @ Phil - Yes, it looks different and the wall thicknesses, for some reason, don't seem to be ideal to me.

  10. Anonymous1:49 PM

    I'm imagining the wheel made of dry cake, and if anything would break it along the middle of the rim bed, I think it would be an unusual pressure on the rim sides outwards..something that would come about my high pressure over sized tires the wheel is not rated for.

  11. Folks spend a lot of time skidding and abusing on the ubiquitous Velocity "Deep V", which has a very similar profile to the H Plus Son rim, yet I've never heard of any catastrophic failures like this.

    I suspect a manufacturing flaw or some other metallurgical failure, perhaps aggravated by abuse but not caused by such.

  12. I just wouldn't buy a wheel off some newcomer to the market however lightweight or flashy looking they may get. I think generally its these companies that would tend to have a lot of those beginner process inefficiencies in the upstream. The trickle down effect is defects and bad products.

  13. Anonymous1:56 PM

    For pete's sake, you buy a rim off a bunch of guys who don't even have a proper website, that's telling something about them. I understand your hurt whoever bought this wheel, but I won't cry with you.

  14. Ron, let me fix that for you: "I just wouldn't buy a wheel off the largest rim manufacturer on the planet however lightweight or flashy looking they may get."

    Seriously... the rims are made by Giant. They are stock rims for the 2009 Giant Bowery (with Giant branded stickers instead of HPS).

    You didn't really think that all these new bicycling brands are created by first investing into million dollar rim welding machines and factories, did you?

  15. Giant Bowery '84 to be exact.

  16. Really? Very interesting asb. I'll have to look into that.

  17. This is where I heard it from:

  18. Anonymous1:34 AM

    if you dont ride fixed i wouldnt expect you to understand, however, ill just say if you get the immense amount of pleasure out of riding your bike as i do "trashing" my fixed gear you may. the added aspect of skidding and other such tricks on a fixed (which may not be for everyone) makes it more than just riding a bike down a road. so if thats what you do..ride a bike in a line, im happy you get your kicks as well but as for the "hipster fixed gear trick session" wouldnt get it and have an unfair bias. oh and sorry my alleycat spoke cards bum you out ill take them out tomorrow morning.

  19. You can do whatever you want with your bike for all I care. However, the issue is doing what the design is limited to. Otherwise, you're just trashing it. I think thats the idea that some people were projecting. I think fixed gear culture, mountain biking, road, track and downhill are all various facets of the kaliedescope that is cycling culture. I'm pretty happy its this varied.

  20. Anonymous1:45 PM

    I had the same problem but was using a steel rim. My tube was over pressurized for the tire and it sounded like someone was poppin caps at me. Then I realized that I was in Belmont shore and my tube had bursted, blowing off my tire completely. Due to the strenght of the steel rim there was only need to replace the tube. To our friend that is uselessy wasting the tread on his skins, let some air out of your groovy pink tires.

  21. Anonymous11:03 PM

    This has little to do with tire pressure, or use, this is an extrusion flaw whereby the rim is extruded over a bridge die, the rim material re-welds along the tire well center, this re-weld went wrong. This combined with the tire well being much too thin (you can see clearly in 2 photos). Tire section can play a role but having made rims for decades I can assure you this is an extrusion failure. Under normal circumstances a rim will have high stresses at the spoke interface, and brake box area, with lowest stress at the tire well center. This tire well is extruded and when the rim is hooped the well thins out, how much it thins out depends on how thick the V section of the rim is. As deep as this rim is the well thins out too much. I can buy some and pressure test these to see what pressure they fail at. I will update here when I see the mode and point of failure.

  22. Anonymous8:14 PM

    So we're to believe this guy's rim exploded simply because he was skidding? Sorry, but I have to call BS on that. Anyone who lives in a city with ANY fixed-gear scene whatsoever or, for that matter, anyone who has EYES can tell you hipsters don't simply skid to stop. They bounce the rear wheel up and down as if they were in an arcade playing Dance Dance Revolution.

    Also, why does this kid have a carbon tri-spoke front wheel on a bike that probably weighs over 22 lbs??? Is it easier to brazenly run red lights while drinking PBR this way? Please help me understand.

  23. Anonymous6:48 AM

    because it looks good


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