Johan Bornman Posted May 3, 2011 Posted May 3, 2011 I have now broken my 3rd spoke on the rear wheel. since December 2010I am getting frustrated as this to me does not seem normal. Perhaps i am doing something wrong - i have had no major offs (i sometimes cant clip out quickly enuf - but this happens to most i assume xt hubs with dt swiss spokes. the spokes all break just above the nipple. it's a PITA to replace because the tyre needs to come off, slime replaced etc... If the spokes break at the nipple, then the wheel is either designed with the wrong number of crosses or, the wheelbuilder didn't take care in improving the spoke line at the nipple. Have a competent wheelbuilder address the issue for you. If he doesn't know what "improving the spoke line" means, then he's probably a hairdresser, not wheelbuilder.
Johan Bornman Posted May 3, 2011 Posted May 3, 2011 Have your chain ever come off between the casette and the spokes? If so, often the spokes get nicked by the chain within a few centimetres from the hub. That weak place then sometimes breaks later. Remember that the drive-side spokes take a lot more strain. Check the spokes behind your casette carefully and replace the ones that look like some clumsy guy took to them with a file. If the breaks happened on the rim side, I cannot help much except to ask about things like jumping and weight..... The OP did tell us that the spokes break at the nipple. This kinda excludes events like the ones you describe. Jumping has nothing to do with the problem either.
Johan Bornman Posted May 3, 2011 Posted May 3, 2011 Apparently the rim was expanding faster than the spokes could handle when the sun hit it. How close to the sun was the bike?
Johan Bornman Posted May 3, 2011 Posted May 3, 2011 I'm having the same problem with my back wheel. LBS told me it may be that my rims are old and flexing too much and I need new ones? Not sure if I can believe him but my MTB is now 5 years old and done fair milage.He's talking through his nose. Find another mechanical confidant.
Cois Posted May 3, 2011 Posted May 3, 2011 One thing... Not sure if it was named, but get a shop that knows how to build wheels. It is not a DIY job if you are not 100% sure of what you are doing.
Johan Bornman Posted May 3, 2011 Posted May 3, 2011 I have also had a spoke shear just as it enters the nipple (XT hub with DT Swiss spokes and DT Swiss 420 rims). I think there may be a bit of corrosion weakening the spoke where it is in contact with the nipple. I doubt it. Stainless steel is impervious to anything a cyclist can throw at it. I had multiple DT Swiss spoke nipples corrode to failure (They eventually crumble and pull out of the rim) on a DT Swiss 455 rim a few weeks ago. Replaced all spokes. This happens with alu nipples but not brass ones. Get brass and be done with it.
RocknRolla Posted May 12, 2011 Author Posted May 12, 2011 ok, so i have gathered from this thread that my wheel was built by an incompetent fool at 4:45 on a friday afternoon, and the only remedy is to have the whole thing rebuilt by a wheelwright guru. but until i can get this sorted, i am still frustrated. I have now (sinse my last spoke fix) broken another 3 spokes. the type of riding i have done: rode around the cradle last weekend, some nice dirt highways, and 5km of the avianto xc singletrack. and then some easy dirt twice a week in the morning. maybe it breaks because it is so cold.... anyhoo, wheel back to the LBS this am, will have to get it sorted before lionman and sani.
Shift Posted May 12, 2011 Posted May 12, 2011 (edited) I had a little incident this weekend at the TruCape race...hit a deep hole at high speed, my entire body weight and bike weight was taken by the frontwheel. I did a few rolls and tumbles down the mountain as I went over the handle bars, the bike stayed in the knee-deep hole. As I walked back to the bike I was expecting the worst...but it was still true, with all the spokes intact! My wheels are Shimano XT... I need to say that it was a great buy,as they have taken quite a beating but still performs brilliantly! Edited May 12, 2011 by Shift
RocknRolla Posted May 16, 2011 Author Posted May 16, 2011 well, the final installment of my spoke saga is that my LBS have finally tired of replacing my spokes, the whole wheel has been re built, with thicker gage spokes Big up to eben from Westrand Cycles. He is sorting the issue out with the importer, as he has had a similar incident with another rider's bike. did the lionmand this weekend hand had 0 issues with my rear wheel.
Johan Bornman Posted May 18, 2011 Posted May 18, 2011 well, the final installment of my spoke saga is that my LBS have finally tired of replacing my spokes, the whole wheel has been re built, with thicker gage spokes Big up to eben from Westrand Cycles. He is sorting the issue out with the importer, as he has had a similar incident with another rider's bike. did the lionmand this weekend hand had 0 issues with my rear wheel. Don't get too excited, too soon. Thicker spokes are almost never a good idea. Double butted and stress relieving is the only combination that will give you wheel durability. The only reason ever to go with straight-gauge spokes or so-called triple-butted is when the wheelbuilder doesn't have time to build the wheel properly (think 8-day races at Ghent or such) or, budget is an issue. A third reason is if a machine is building your wheels but that's another story altogether.
Chavez Posted May 20, 2011 Posted May 20, 2011 I'm struggling with the same issue. I've had my Giant Composite TCR (road bike) since Jan and snapped my second rear spoke (on the hub) on this mornings ride We were 30km from the start riding out. Wheel warps and I can't ride the bike so landed up walking back while my mate Dommisse went to fetch the bakkie. I'm not a rough rider on the bike...my weight is a little on the heavy side, 102kg, but was told the wheels can easily handle my size. Bike's going back to the LBS today so that they can have a look.
DaLoCo Posted May 20, 2011 Posted May 20, 2011 How close to the sun was the bike? Somewhere between 147 million to 152 million kilometres, I would hazard a guess of around 148 million kilometres, as it happened around February Oh...uh sorry You were trying to mock me Then explain how a bike that has not been ridden offroad till that point breaks spokes whilst standing next to a glass door that catches the morning sun. I was within 2 m of the bike when the last one snapped, so I know it was not knocked, handled, even touched. It was just merrily standing in the morning sun. I do remember checking what the noise was, and finding the rim quite hot, and then only saw the broken spoke. I am not questioning your vast experience and knowledge (not being sarcastic, as you do give sound advice) but I am calling it the way it happened. My reasoning says that the spokes should have expanded as well, thus not causing any issues. After the first few breakages I did take a closer look at the wheel, so did the LBS, and they did not see any damaged spokes, but yet a few more broke.
MoreTrails Posted May 20, 2011 Posted May 20, 2011 A question - was / is this wheel a parts picked (and agonised over), hand built variety or is it a standard factory / machine built individual? If it is the latter you may have got a dud, inferior material quality??? If it is the former, well then I am not sure cause if the wheel is built correctly it should last yonks. Maybe just have the wheel respoked by a wheel builder and go for some straight gauage 2.0 spokes? It may boil down to the way you ride. Maybe you move on the bike or the bike moves in the air that puts more loading on the wheel developing weak areas in the spokes....if this is possible?
Johan Bornman Posted May 20, 2011 Posted May 20, 2011 Somewhere between 147 million to 152 million kilometres, I would hazard a guess of around 148 million kilometres, as it happened around February Oh...uh sorry You were trying to mock me Then explain how a bike that has not been ridden offroad till that point breaks spokes whilst standing next to a glass door that catches the morning sun. I was within 2 m of the bike when the last one snapped, so I know it was not knocked, handled, even touched. It was just merrily standing in the morning sun. I do remember checking what the noise was, and finding the rim quite hot, and then only saw the broken spoke. I am not questioning your vast experience and knowledge (not being sarcastic, as you do give sound advice) but I am calling it the way it happened. My reasoning says that the spokes should have expanded as well, thus not causing any issues. After the first few breakages I did take a closer look at the wheel, so did the LBS, and they did not see any damaged spokes, but yet a few more broke. My comment was truly in jest, no malice intended. The whole mechanism of spokes that break is so poorly understood that I had to smile when I saw that comment of yours. With breaking spokes, lots of people will tell you that the spoke broke when they hit a bump, yet that is seldom the case, since spokes are at their lowest tension when hitting a bump (I'm talking about the spokes at the bump zone now) and therefore, they didn't break when you hit the bump but when you came out of the bump and that one last extension was what they couldn't handle. If you analyse the break, you'll notice that it is absolutely flat and straight as if a laser cut it. If you look closer, you'll see two different zones in the break. The one zone is grey and has directinal arcs across it, indicating the direction of the crack's travel. The other zone is small and shiny and actually has a little point to it. This is the last bit to break and the only bit to break in tension. The rest (99.9% of the surface area of the crack) all broke through fatigue, not tension. Have a look at the photo. The break is clean, typical of a fatigue break. The crack travelled from the bottom to the top. The last little silver bit is the bit that broke when your rim expanded in the sun. It just goes to show how little action is acqually required to break a spoke. Truth is, it was broken before the sun shone on it, it just wasn't separated yet.Thanks for sharing your story, it illustrates a point I should have made earier, very well.
Johan Bornman Posted May 20, 2011 Posted May 20, 2011 A question - was / is this wheel a parts picked (and agonised over), hand built variety or is it a standard factory / machine built individual? If it is the latter you may have got a dud, inferior material quality??? If it is the former, well then I am not sure cause if the wheel is built correctly it should last yonks. Maybe just have the wheel respoked by a wheel builder and go for some straight gauage 2.0 spokes? It may boil down to the way you ride. Maybe you move on the bike or the bike moves in the air that puts more loading on the wheel developing weak areas in the spokes....if this is possible? Why do you believe straight gauge 2mm spokes will be better? Also, the scenario in the last sentence is not possible.
DaLoCo Posted May 20, 2011 Posted May 20, 2011 I neglected to look at the breaks closely, but I suspect you are right Johan, I probably would've found signs of metal fatigue. But the bike did stand in the morning sun for about five months whilst I was playing around on my road bike (and waiting for selfish mtb'ers to me take out on trails) What I did not understand though is that the bike had not seen any dirt roads up to that point. The first time I went off road (fairly rough and corrugated) three spokes broke, so I had the wheel rebuilt like you suggest. I have not had any issues since
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