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Re: [rootsradicals] rim failure (was: Random stuff)

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  • gear.head@verizon.net
    I have actually seen that happen just from fatigue. Two in fact; the riders were in the 175-195 lb range who ride a lot. There is other factors that can
    Message 1 of 27 , Jul 9, 2011
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      I have actually seen that happen just from fatigue. Two in fact; the riders were in the 175-195 lb range who ride a lot. There is other factors that can contribute such as high spoke tension, aggressive riding etc. In both cases before they failed the rim was not staying true.

      Just some insight.

      Note: the bikes mentioned were ridden on and off road and were not long tails.

      Sent from my Verizon Wireless BlackBerry


      From: "jparks781" <joel.parks@...>
      Sender: rootsradicals@yahoogroups.com
      Date: Sat, 09 Jul 2011 15:57:00 +0000
      To: <rootsradicals@yahoogroups.com>
      ReplyTo: rootsradicals@yahoogroups.com
      Subject: [rootsradicals] rim failure (was: Random stuff)

       

      David,

      what rim was that?

      what tire pressure range do you try to maintain?

      how many miles approx.?

      was it on your Dummy? Did you move it from your previous X to the Dummy?

      Why do you fault the wide tire? I'm trying to figure out the mechanics / geometry of how the wider tire might have exacerbated the problem.

      I ask because I'm running Big Apples on Velocity Cliff Hangers, which are fairly narrow rims, 1.125" outside width. The Big Apples measure a little over 2.4" wide on these rims at 60psi.

      Although I weigh ~145#, so that may keep me out of trouble. Also you are a much more faithful cycle-commuter than I, I'm sure your putting a lot more miles on the bike.

      Joel

      --- In rootsradicals@yahoogroups.com, David Chase <dr2chase@...> wrote:
      >
      > A couple of things:
      >
      > ...
      >
      > It's a bad idea to run a really fat tire on a relatively thing rim. http://gallery.mac.com/dr2chase/100060/IMG_4810/web.jpg?ver=13091391700001
      >
      > ...
      >
      > David
      >

    • David Chase
      ... DT Swiss XR4.1. ... 60 psi ... 2500/year (but not all on those tires, snow tires in winter) ... No, I had bought it used to replace the dead hub from last
      Message 2 of 27 , Jul 9, 2011
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        On 2011-07-09, at 11:57 AM, jparks781 wrote:

        > David,
        >
        > what rim was that?

        DT Swiss XR4.1.

        > what tire pressure range do you try to maintain?
        60 psi

        > how many miles approx.?
        2500/year (but not all on those tires, snow tires in winter)

        > was it on your Dummy? Did you move it from your previous X to the Dummy?

        No, I had bought it used to replace the dead hub from last year. Guy who owned it before me had it on a recumbent trike for about a year, with skinny tires. Not a light guy either, but probably not so many miles on it (he has spinal stenosis, which makes many things difficult, and why he was selling the wheel).

        > Why do you fault the wide tire? I'm trying to figure out the mechanics / geometry of how the wider tire might have exacerbated the problem.

        My thinking is that the wide tire leaves the rim perpendicular to the rim edge, so the full tension in the tire is applied to the rim -- that is, pulling the rim apart, instead of pulling up off the rim. Because otherwise, there is "no difference" between a 60mm tire at 60psi, and a 30mm tire at 120psi (but note that 120psi 30mm tires are not usual case). The tension in the casing, is proportional to the diameter of the tire, times the pressure -- image slicing an inflated tire like a bagel, and the area of the bagel corresponding to an inch of bagel circumference.

        > I ask because I'm running Big Apples on Velocity Cliff Hangers, which are fairly narrow rims, 1.125" outside width. The Big Apples measure a little over 2.4" wide on these rims at 60psi.

        The Cliff Hangers are plenty wide, I think, 28mm outside width. The rim I broke was 17 mm inside width, 22 mm outside width.

        > Although I weigh ~145#, so that may keep me out of trouble. Also you are a much more faithful cycle-commuter than I, I'm sure your putting a lot more miles on the bike.

        I am not sure that the rider weight matters that much, though to the extent that the tire deforms to be even more perpendicular, that should spike the tearing force.

        David
      • sh8knj8kster
        ... ~~~Cara, I think you re talking about Sue Brown...here s her big dummy blog http://xtrasue.com/category/thebd/ Best, Jake Reddick Fla. He was a very
        Message 3 of 27 , Jul 12, 2011
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          --- In rootsradicals@yahoogroups.com, Cara Lin Bridgman <shokulan@...> wrote:
          >
          > Somewhere on this list, another woman posted about outfitting her big
          > dummy with smaller wheels because she was so short. I don't think she
          > bothered with shorter cranks. She posted links to pictures. Sorry, but
          > I can't remember when or key words.
          >
          > Frankly, pedal strike when cornering is an over-rated problem. It's
          > definitely easy to learn to adjust pedals for sharp turns. I find I do
          > it automatically.
          >
          > CL
          >





          ~~~Cara, I think you're talking about Sue Brown...here's her big dummy blog http://xtrasue.com/category/thebd/


          Best,


          Jake
          Reddick Fla.
          He was a very cautious man who never romped and played
          He never smoked, He never drank, Nor ever kissed a maid
          And when he up and passed away his insurance was denied...
          For since he hadn't ever lived, they claimed he never died


          http://www.shakinjake.blogspot.com/
          http://www.flickr.com/photos/26137108@N04







          > doreavc wrote:
          > > I love this list! All these ideas are extremely helpful. Hadn't thought of smaller wheels. I got a measurement of 24" to the lowest point on the Sun at the bikeforum Sun Atlas thread, which is encouraging, and I'll be taking a look at these suggested frames. @David -- thanks specifically for the local shop suggestion.
          > >
          > > --Dorea
          > >
          > >
          > >
          > > --- In rootsradicals@yahoogroups.com, "doreavc" <doreavc@> wrote:
          > >> We currently ride with a mountain-bike type frame and a free-radical extension, frequently with our two kids loaded on the back, see here:
          > >>
          > >> http://carfreecambridge.com/wp-content/uploads/2010/07/3885459958_e1df437a74.jpg
          > >>
          > >> (we've since swapped out the handlebars and added a kickback but you get the idea)
          > >>
          > >> For the most part, this has worked well, but my very short (5'1") wife is getting frustrated with getting on and off, and is wishing for a step-through frame, especially since our kids are little, so we have to load them first so she can't just swing her leg up over the back.
          > >>
          > >> So we're trying to find a more step-through option. In comparing the more "pre-fab" choices out there, it looks like the big dummy is out. It doesn't look like the radish, yuba mundo, kona ute or the new sun atlas are truly step through. Does anyone have standover heights on any of these? As in measurement from the ground to the frame at the lowest point you could get a leg through to mount? The Sun Atlas looks like it *might* be the lowest (our current bike is about 26"). We don't really have space for it, but I'm seriously considering a Madsen since it looks like one of the easiest to get on and off.
          > >>
          > >> I'm also considering using our existing free-radical on a different bike, in which case we'd be looking for something with 26" wheels, ideally disc brake compatible. I got a recommendation for the Breezer Uptown 8, but am not so sure about the aluminum frame with such a low step through when we'll be riding it pretty heavily loaded. Has anyone found a step through frame that works really well with the free radical? Has anyone tried one of the Linus bikes?
          > >>
          > >> We're in the Boston/Cambridge area. If anyone in this area has something they think might fit the bill that we could test ride, please let me know.
          > >>
          > >> Thoughts welcome and thanks!
          > >> Dorea
          > >> Carfree with Kids: http://carfreecambridge.com
          > >>
          > >
          > >
          > >
          > >
          > > ------------------------------------
          > >
          > > You're getting this message because you signed up to be an Xtracycle roots radical.
          > >
          > > To Post a message, send it to: rootsradicals@yahoogroups.com
          > >
          > >
          > > ride to believe.Yahoo! Groups Links
          > >
          > >
          > >
          > >
          >
          >
          > --
          >
          > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
          > Cara Lin Bridgman cara.lin@...
          >
          > P.O. Box 013 Shinjhuang http://megaview.com.tw/~caralin
          > Longjing District http://www.BugDorm.com
          > Taichung 43499
          > Taiwan Phone: 886-4-2632-5484
          > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
          >
        • Cara Lin Bridgman
          Thanks Jake, that s the one. At her blog, she explains the sizes and all the things that got cut down to her size. CL
          Message 4 of 27 , Jul 12, 2011
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            Thanks Jake, that's the one. At her blog, she explains the sizes and
            all the things that got cut down to her size.

            CL

            sh8knj8kster wrote:
            >
            > ~~~Cara, I think you're talking about Sue Brown...
            > here's her big dummy blog http://xtrasue.com/category/thebd/
            >
            > --- In rootsradicals@yahoogroups.com, Cara Lin Bridgman <shokulan@...> wrote:
            >> Somewhere on this list, another woman posted about outfitting her big
            >> dummy with smaller wheels because she was so short. I don't think she
            >> bothered with shorter cranks. She posted links to pictures. Sorry, but
            >> I can't remember when or key words.
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