Why did my bicycle have a spoke shatter and a tube rupture?

Question

Some days and one and off, I had been having squeaking sound from the bicycle- couldn't pin down the location other than rear of the bike. Suddenly when crossing the road while at low gear, a spoke shattered- I didn't know what happened. I pushed the bicycle slowly to a bicycle shop but they couldn't fix it and directed me to a distant bicycle shop. The wheel was out of alignment. The spoke had only the rim attachment. I riding slowly with a light load to a bicycle shop - trying a slightly further one where I had bought it and was more convenient and there was a boom and the tube had ruptured. I was under pressure because my son was home from school and I was meant to look after him soon. What happened and how to prevent it? The bicycle shop replaced the entire tire and tube and spokes within a few hours. There was never an option to keep the original tire. By the way This is the bicycle. I live in Japan and can't converse with bicycle repairer. My new bicycle skids laterally, especially in the wet; what can I do about it?

My father-in-law called them and he could only get the information that they replaced the tire and the tube and three spokes. Also suddenly realised how rough the pedals with a bit knocking like the bearing are faulty and occasional squeaks from that area.

Answer 1

Guessing: you had one spoke break at the J bend and the rivet end was lost. The remaining part of spoke popped the tube from below, perhaps it was a little sharp? And the tyre on the outside was worn enough to need replacement anyway.

If this is the case, there's a non-zero chance it will happen again - spokes break like this from running with low tension so they stress and get weak at the bend. Your bike shop should have checked the rim's true and tensioned other spokes that were low.

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If the spoke had broken in the middle, it would more likely be from damage giving a weak point. Impacts, nicks, or even a thin spot from where two spokes rub can cause a weak spot over time.

"The spoke shattered" suggests there were multiple pieces. For a metal spoke to do this is unlikely - they almost always break in one place giving two pieces.

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The authority on why the LBS did what they did is the mechanic at the shop. Try ringing them up and asking for more explanation. We can only deduce so-much from the description.

Answer 2

From your mention of a squeaking sound some time before this all happened, I guess that your wheel has been out-of-true for quite some time. So much so that the tire was rubbing against some other part (chain stay, seat stay, brake (pad)). This kind of rubbing will destroy the tire over time. Note that the rubbing may not be present when your wheel is unloaded on a test stand, and thus the source of the rubbing may be hard to pin down. However, there is only a single place on a bike where rubber may rub against something, so the sound gives the condition away. Look for rub marks on the flanks of the tire.

Now, when your spoke broke, the situation worsened significantly. This is to be expected. And it likely accelerated the wear on the already weakened tire. A tire that has a flank deteriorated may burst at any time, producing a loud bang and a big hole/slit on the side. And I really mean any time. I've had a tire do the same thing while sitting still on the parked bike.

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How to prevent this? Well, first of all, you need to be vigilant about untrue wheels. You also need to be wary of under-tensioned spokes. You may easily check spoke tension by hitting each spoke with a wrench or similar. All spokes should produced a ping sound of similar pitch, no spoke should ever give a dull plong. The more similar the pitch, the better. Also note, that wheels get out-of-true virtually only when they are poorly built. Either because of too low spoke tension (unloading spokes while riding), because of too high spoke tension (killing spokes/flanges/rims), or because of uneven tension (unloading spokes while riding, again). It's the wheel builder's job that determines how long your wheel will last, much more than the material.

And, whenever you hear rubber squeaking, you should investigate immediately to prevent damage to your tire.