Capcha Posted December 9, 2012 Share for the second time in a week i just broke another spoke this time taking the derailer with it. Luckily i had just finished the ride and was about 1km from home. Taking it back to shop where i got it fixed last week. My tech knowledge tells me they did not tension the spokes properly and probably only replaced the one spoke. am i missing something else it could be thats breaking my spokes all of a sudden? Edited December 9, 2012 by Capcha Photography Link to comment Share on other sites More sharing options...
M L Posted December 9, 2012 Share In what back gear where you? Maybe your rd is touching the spokes when on the highest gear? Link to comment Share on other sites More sharing options...
Johan Bornman Posted December 9, 2012 Share Are you sure you have the order of events right? A broken spoke very seldom takes a derailer with it. However, a broken derailer or jammed derailer always breaks spokes. Spokes that break for no obvious reason failed due to metal fatigue and the break is very characteristic - straight, square and clean. A spoke that broke because of derailer and chain issues is a dog's breakfast. Which is which? Link to comment Share on other sites More sharing options...
Capcha Posted December 9, 2012 Share ah johan u will know. first the ching then hear spoke hitting the frame then derailer coming off. last time it was just the spoke. when i put down hard power(watts) then it happens Link to comment Share on other sites More sharing options...
T-man Posted December 9, 2012 Share Happened to me last year. wheel rebuild..no probs from there Link to comment Share on other sites More sharing options...
Cippo Posted December 9, 2012 Share How old are your wheels Capcha? I bought a 2006 bike two years ago that had barely seen 500 km and had been standing in a garage. I broke 4 spokes after 6 months of riding. Even if bike has been standing its possible for spokes to rust if they not stainless steel. Rebuilding wheels can be expensive and not really worth it if they are entry level wheels. I just went out and bought some Mavic Aksiums for training. Link to comment Share on other sites More sharing options...
Capcha Posted December 9, 2012 Share 2012 sst 2.0 fuji with 38mm oval rims. it really shouldnt be breaking and im 8kg lighter than when i bought the bike. Edited December 9, 2012 by Capcha Photography Link to comment Share on other sites More sharing options...
Johan Bornman Posted December 9, 2012 Share OK, so it seems your spokes did break from metal fatigue and you were just very unlucky. Usually it is a non-event. Weight has very little do do with it and age absolutely zero to do with it. A million year old wheel that hasn't ridden will still be "unfatigued." Metal fatigue in spokes come from poor wheelbuilding the wheelbuilder doesn't understant the concept and purpose of stress relieving. A stresss-relieved wheel has a near infinite spoke life. The repair mechanic's first clue should have been the mode of spoke failure. He then should have advised you that if one spoke broke from fatigue, the others are on their way out too. Tension here was not the issue, but stress relieving. Either do like Chippo here says or have them rebuild with double-butted spokes by someone who understands stress relieving. Only the very cheapest bikes nowadays have galvanised steel spokes, they're just about all stainless, so I doubt that rust played a role. Besides, spokes that can rust are of such poor quality that they break quicker from fatigue than from rust, even at the coast. DaLoCo and Cippo 2 Link to comment Share on other sites More sharing options...
The Ouzo Posted December 9, 2012 Share I went through this too. The LBS even went as far as suggesting I ride with a wider rear tyre (suggesting in a nice way that I'm to heavy).After they fixed the wheel for the 2nd time I notice it was out of round. I had an independent guy rebuild it after that.No issues since. Flowta 1 Link to comment Share on other sites More sharing options...
Capcha Posted December 9, 2012 Share OK, so it seems your spokes did break from metal fatigue and you were just very unlucky. Usually it is a non-event. Weight has very little do do with it and age absolutely zero to do with it. A million year old wheel that hasn't ridden will still be "unfatigued." Metal fatigue in spokes come from poor wheelbuilding the wheelbuilder doesn't understant the concept and purpose of stress relieving. A stresss-relieved wheel has a near infinite spoke life. The repair mechanic's first clue should have been the mode of spoke failure. He then should have advised you that if one spoke broke from fatigue, the others are on their way out too. Tension here was not the issue, but stress relieving. Either do like Chippo here says or have them rebuild with double-butted spokes by someone who understands stress relieving. Only the very cheapest bikes nowadays have galvanised steel spokes, they're just about all stainless, so I doubt that rust played a role. Besides, spokes that can rust are of such poor quality that they break quicker from fatigue than from rust, even at the coast.Ja you see JB i have a feeling they just replaced the spoke last and did not worry too much about trueing the wheel as it was 2 days before die burger. Anyway, will take the wheel back with the bike as they need to replace the auluminium piece on the carbon frame where the derailer fits onto. do u think i should tell them to replace all the nipples on the rim that way i know they did them all? Link to comment Share on other sites More sharing options...
Cruz Addict Posted December 9, 2012 Share Ja you see JB i have a feeling they just replaced the spoke last and did not worry too much about trueing the wheel as it was 2 days before die burger. Anyway, will take the wheel back with the bike as they need to replace the auluminium piece on the carbon frame where the derailer fits onto. do u think i should tell them to replace all the nipples on the rim that way i know they did them all? not to say the bike shop you are using is dishonest in anyway but i would mark the current spokes, a scratch each or something like that, and ask for the build, this way you are sure it is a rebuild not a fix job. as i say its not a lbs bashing session but its way to easy to say the wheel has been rebuilt when it has not. personally i dont trust anybody to build a wheel but JB, have yet to do a build with him but his ethics etc speak for themselves. if you have a spoke wrench you could even do the strip down yourself and only take in the hub and rim, some shops charge extra for the breakdown. Link to comment Share on other sites More sharing options...
Johan Bornman Posted December 9, 2012 Share Ja you see JB i have a feeling they just replaced the spoke last and did not worry too much about trueing the wheel as it was 2 days before die burger. Anyway, will take the wheel back with the bike as they need to replace the auluminium piece on the carbon frame where the derailer fits onto. do u think i should tell them to replace all the nipples on the rim that way i know they did them all?It is difficult to speculate what exactly happened but I don't suspect foul play. At most ignorance or conservative behaviour. I'll explain. Whether the wheel was trued or not, your spoke would have broken. The truing had nothing to do with it. Fact is, spokes fatigue from cyclical stresses. With each revolution they stretch and relax a minute amount. Just like when you were at school and burnt your friend's leg with a piece of coat hanger wire than you furiously bent forwards and backwards until sizzling hot and having the wire eventually break, spokes break in the same mode. The crystals that make up the metal separate from repeated stresses. Since all spokes cycle exactly the same number of times per ride, they are all fatigued and will all break soon. What the bike shop could have done is explain this to you and then cautioned you that replacing one spoke only will soon have you come back again. Then you could have chosen to take a chance or bite the bullet. I find that people are often not psychologically ready for an expensive rebuild and first want to "take a chance" and see if I'm not talking nonsence. I then replace the spoke and stress the hell out of the remaining ones using an old left crank, just to see if any others are going to break imminently. Often two or three break in the bench. At least I then know that the wheel will be good for a week or three and explain this to the customer. They're back very quickly, redoing the whee completely. Usually it is ok to be conservative and leave the front wheel as is. A front wheel takes far longer to fatigue since it carries less weight and has the shock absorbing benefit of the fork -whether a rigid or suspension fork. Captain Fastbastard Mayhem 1 Link to comment Share on other sites More sharing options...
Capcha Posted December 9, 2012 Share It is difficult to speculate what exactly happened but I don't suspect foul play. At most ignorance or conservative behaviour. I'll explain. Whether the wheel was trued or not, your spoke would have broken. The truing had nothing to do with it. Fact is, spokes fatigue from cyclical stresses. With each revolution they stretch and relax a minute amount. Just like when you were at school and burnt your friend's leg with a piece of coat hanger wire than you furiously bent forwards and backwards until sizzling hot and having the wire eventually break, spokes break in the same mode. The crystals that make up the metal separate from repeated stresses. Since all spokes cycle exactly the same number of times per ride, they are all fatigued and will all break soon. What the bike shop could have done is explain this to you and then cautioned you that replacing one spoke only will soon have you come back again. Then you could have chosen to take a chance or bite the bullet. I find that people are often not psychologically ready for an expensive rebuild and first want to "take a chance" and see if I'm not talking nonsence. I then replace the spoke and stress the hell out of the remaining ones using an old left crank, just to see if any others are going to break imminently. Often two or three break in the bench. At least I then know that the wheel will be good for a week or three and explain this to the customer. They're back very quickly, redoing the whee completely. Usually it is ok to be conservative and leave the front wheel as is. A front wheel takes far longer to fatigue since it carries less weight and has the shock absorbing benefit of the fork -whether a rigid or suspension fork.OK great. Will take in and tell them to replace all spokes and nipples. Thanks for all the feedback guys. Edited December 9, 2012 by Capcha Photography Link to comment Share on other sites More sharing options...
DR ◣◢ Posted December 9, 2012 Share Once a wheel starts breaking spokes due to metal fatigue its best to just rebuild. As a quick fix for a race you can replace the offending spokes but best have the wheel rebuilt. Broke 4 spokes three days before the 24 hour. Replaced them the night before and while redoing the tension on the wheel and truing it another one broke. Sucked hard but I was lucky to have a spare wheel to borrow a spoke from. Wheel will be rebuilt when I go on leave. They date back to 2004 and have done a lot of hard miles under me. Very happy with the performance I got from them. So much so that I will keep them as a spare set for a future project build. Link to comment Share on other sites More sharing options...
Johan Bornman Posted December 9, 2012 Share OK great. Will take in and tell them to replace all spokes and nipples. Thanks for all the feedback guys. Make sure they use double-butted. Link to comment Share on other sites More sharing options...
DR ◣◢ Posted December 9, 2012 Share Johan, apart from the weight advantage, any other reason for using double butted spokes? Link to comment Share on other sites More sharing options...
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