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Broken spoke on Saturday.

Monday, August 18, 2014 by  
Filed under Daily Blog

August
18
2014

On Saturday’s ride my bike suffered a ride-ending mechanical: a broken rear wheel spoke. The spoke broke shortly after I’d completed the solo 22 kilometer (13.5 mile) ride to meet my club for the main ride. We had only just set off, and I heard a loud “pop”! I didn’t hear anything rubbing, but a fellow rider pedaled up to me and said my rear wheel had a bad wobble. As soon as he said that, I knew I’d broken a spoke. I pulled off the road, and sure enough, one of the spokes was broken off at the spoke nipple.

I sort of knew this was coming. In fact, I was planning to take my rear wheel (Zipp 404 Firecrest) to my local Zipp dealer to have all the spokes replaced before Six Gap. The reason I wanted to have the spokes replaced is because more than half of them were twisted to various degrees. Despite my best efforts to prevent it, this twisting occurred during regular truing of the wheel:

As you can see, this spoke is twisted. There are several spokes in this condition, and I suspect this is what caused my broken spoke.

As you can see, this spoke is twisted. There are several spokes in this condition, and I suspect this is what caused my broken spoke.

 

Zipp wheels have bladed spokes, and Park makes a tool (the BSH-4) which is designed to prevent spoke twist while truing:

This is Park Tool's Bladed Spoke Holder (BSH-4) tool. Even though I use this tool when truing my wheels, sometimes the spokes still twist.

This is Park Tool’s Bladed Spoke Holder (BSH-4) tool. Even though I use this tool when truing my wheels, sometimes the spokes still twist.

 

Of course I use this tool when I’m truing my wheels, but often the spokes are badly stuck at the nipple and twisting still occurs. I use a couple drops of lube on the nipple before truing, and I use a spoke wrench to try and loosen the nipple from the spoke (with small back and forth quarter turns), but sometimes the spokes still twist before they “pop” free.

The interesting thing is that my front wheel never has any spoke twisting issues, it’s just the rear one. The rear wheel came direct from Zipp’s factory to me (they rebuilt it after a crash), and I don’t think that’s a coincidence. I was talking with Richard Dybdahl–a fellow WMBC bike club rider and owner of Pure Cycles in Eustis–and he mentioned WheelSmith spoke prep. The product is designed to prevent binding caused by corrosion, and I wonder if perhaps Zipp failed to use it when they built up my crash replacement wheel? That would explain a lot.

Anyway, after the spoke broke I elected to not tighten the other spokes to bring the wheel somewhat back into true, as I didn’t want to risk damaging the wheel itself. Lisa came and picked me up, and when I got home I grabbed my rear indoor trainer wheel (relatively heavy and far from aero, but strong and true), threw my road tire on it and hit the road in an attempt to find my group. I never did find them, but at least I got some more miles in.

Yesterday I did a 167 kilometer (104 mile) ride, and a couple of interesting things happened on that ride, too. Those tales will need to wait until tomorrow, as I’m running behind schedule and I need to wrap this up and get my day going. See you tomorrow!

John Stone Fitness Comments

3 Responses to “Broken spoke on Saturday.”
  1. Wheel is at Zipp dealer. Galvanic corrosion is the problem, and it’s very bad–especially considering how new this wheel is. I asked about using brass spoke nipples instead of aluminum, and that’s what I’m going with when they re-lace it. There’s a very slight weight penalty with brass nipples, but no more corrosion problems. Well worth the few extra grams, IMO.

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  2. In addition to putting oil on the spoke/thread interface, I also put a drop on the interface between the spoke head and the hole in the rim — where metal also contacts other metal. Corrosion can occur at either point, and plain old grit/dirt is more likely between the spoke head and the rim.

    In both cases, I hit every spoke and then give the wheel a good spin to allow centrifugal force to carry the lube down into the threads or into the wheel. Looking at the amount of wind-up you’re getting on your spokes, it might be worth doing this every month or so.

    Spoke-Prep is designed to cover both ends of wheel’s life: the build initially and it’s ride-life as well. Their lofty claims can be seen below, but for years before the product (and many others) was available, shops used linseed oil, which lubed the threads on the build and then gelled afterword to help hold the spoke in place.

    From Wheelsmith:

    The ultimate spoke thread compound is SpokePrep™ because it is both a lubricant and a thread lock! How can it do both? When spoke tension is low and there is risk of loosening, SpokePrep “locks” the nipple by maintaining a minimum nipple torque. When spoke tension is high SpokePrep keeps nipple torque low with Teflon lubrication. We also have SpokePrep in two colors so you can prep your spokes and immediately know on which side of the wheel they will be used. Available in two sizes.

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    • The procedure you described before truing is virtually identical to what I do, too.

      I’ve actually learned quite a bit about this issue in the short time since I wrote this blog, including causes, preventatives and a method for freeing corroded nipples/stems. I’ll talk more about all this in Wednesday’s blog.

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