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Clydesdales/Athenas (200+ lb / 91+ kg) Looking to lose that spare tire? Ideal weight 200+? Frustrated being a large cyclist in a sport geared for the ultra-light? Learn about the bikes and parts that can take the abuse of a heavier cyclist, how to keep your body going while losing the weight, and get support from others who've been successful.

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Old 06-07-09, 05:56 PM   #1
moose67
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It happened sooner than expected, I popped a spoke

I was riding with my wife yesterday afternoon before we left for a wedding. We were riding the bike path at the Headquarters library in Jonesoro, GA. I had extended the ride to a new personal best (especially for being an uber-clyde). We rode over 6 miles on the fairly flat bike path. Even with gearing an uber-clyde has to fight physics and that ain't easy. At what I've measured as the 1/2 mile mark when starting the ride I was passing that point on my way back to the truck when I heard a pop and noticed the bike didn't quite feel right. I pedaled for a little while and it was ok but in the back of my mind I figured something happened. As I loaded my bike in the truck I grabbed a couple of spokes just to test and as luck would have it I grabbed in the right area. They felt a little loose then I grabbed another and found the broken one. I popped near the hub. Is that common to pop there? Since April 1st including yesterday and some crappy weather for the month of May and a busy schedule I have ridden 70.42 miles. My goal originally was to be at over 15 miles by the end of the summer. I'm hoping to be at over 10. If I can get above 10 by the end of August I'll be extremely happy. My Carmel 3 26 has been great and the guys at Epic Bikes in McDonough, GA are awesome. I'll be seeing them Monday or my wife will if I can fit the bike in her vehicle.
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Old 06-07-09, 06:06 PM   #2
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How large are you if you don't mind me asking?
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Old 06-07-09, 07:06 PM   #3
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I don't mind the question. I'm in the area of #450. I ride only on sidewalks, smooth pavement and bike paths.
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Old 06-07-09, 07:07 PM   #4
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Sensitive question, to be sure, but it can make a difference for wheel building advice. We've all been there or still are. Heck im 285-I should wear it on my sleeve...it might spur me on more!

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Old 06-07-09, 07:21 PM   #5
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It popped near the hub. Is that common to pop there?
Yes, at the hub and usually on the side with the chain since spokes on that side are more heavily tensioned. If you continue to have problems I'd suggest going to a wheel made for tandem use with more spokes. Our tandem rear wheel has 48 spokes and has been very reliable. Previously we had long-standing problems with broken spokes on the original 36-spoke wheel.
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Old 06-08-09, 02:17 AM   #6
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As stated above, try a tandem wheel setup. I have a 40 spoke with tandem hub setup on my bike.
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Old 06-08-09, 08:44 AM   #7
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From my limited (but unfortunately quickly growing) experience with broken spokes, for us clydes, it's on some level at least, all about spoke count. I'm close to 300 and have a box-store-purchased Schwinn hybrid. Frame and components are all nice enough for me at this point, for sure, but the 24-spoke wheels - not so much. Two incidences of broken spokes in rapid succession after about 200 miles in the saddle convinced me of that. From what I've gathered in researching online and reading other threads here in BF, spokes break most often at the hub or at the nipple (where it screws into the rim), so sounds like yours broke in a to-be-expected spot.

I'm switching to from 24 spoke wheels to 36 spokes, but only after learning the hard way, so +1 on the recommendations to look into tandem wheels or others with more spokes.
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Old 06-08-09, 04:20 PM   #8
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From my limited (but unfortunately quickly growing) experience with broken spokes, for us clydes, it's on some level at least, all about spoke count. I'm close to 300 and have a box-store-purchased Schwinn hybrid. Frame and components are all nice enough for me at this point, for sure, but the 24-spoke wheels - not so much. Two incidences of broken spokes in rapid succession after about 200 miles in the saddle convinced me of that. From what I've gathered in researching online and reading other threads here in BF, spokes break most often at the hub or at the nipple (where it screws into the rim), so sounds like yours broke in a to-be-expected spot.

I'm switching to from 24 spoke wheels to 36 spokes, but only after learning the hard way, so +1 on the recommendations to look into tandem wheels or others with more spokes.
It's not all about spoke count, it's about spoke stress. The first thing that causes spoke stress is low spoke tension. There are other factors as well that cause spoke stress, such as a heavier load, and rim stiffness. Let me explain.

Note I say, load weight rather then rider weight, a 150lb touring rider with 85lbs of gear puts the same stress on a wheel as a 235lb rider, depending on how it's distributed.

As a wheel goes around, the load weight is placed on the spokes at the point where the tire touches the ground, if tension is low, it causes the spokes to bend slightly, usually at the bend where it enters the hub. What happens when you repeatedly bend a steel wire, it breaks. If the spokes are properly tensioned for the load on the wheel, then the spokes are tight and do not bend. Rim stiffness, which is the ability for a rim to maintain a perfect circle under load, is also a factor, and rim cost and stiffness are not always related. Cheap single wall rims, tend not to be very stiff, so they will flatten slightly at the bottom, this temporarily reduces spoke tension and can lead to spoke breakage. Very high end super light weight rims, are also not as stiff, this is less of an issue for skinny road racers then it is for Clydes.

Higher spoke count means that the stress placed on the spokes is more spread out, so even if tension is a little low, or the rim isn't as stiff as it should be for the load, each spoke is stressed less then with fewer spokes, so the likelyhood of a spoke breaking is lower, which is why spoke count seems to be important. One thing, the rear wheel is the one that takes most of the load, about 60%, on a bicycle with a rear rack that is carrying a heavier item this can easily end up 70% or more.

Most bicycle wheels are made on machines, these machines have a problem, as tension increases there is a higher tendency for a spoke to twist when the nipple is turned (called spoke windup), the machines have a problem detecting this, so they either ignore it, or leave tension below the point where spoke windup tends to become an issue. If the machine ignores it, then as soon as load is placed on the wheel the spokes unwind and you end up with low tension. A human wheel builder can easily detect spoke windup and compensate for it. Not all bike shops have a wheel builder. Replacing one machine built wheel with another, often leads to the same problem.

The normal steps are these, if your having problems with breaking spokes:

1) Get the spoke replaced and the wheel tensioned.
2) Replace all spokes and get the wheel tensioned.
3) Replace the wheel with a wheel that has a stiffer rim and more spokes. Get wheel properly tensioned before riding, and re-tensioned after 300miles/500km.

Consider each wheel independently, often the rear wheel causes the problem, with the lower load on front wheels, they tend not to have problems.

Last edited by Wogster; 06-08-09 at 04:23 PM.
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Old 06-08-09, 04:37 PM   #9
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Wogster,
Are you aware that the OP is 450 lbs.? While this doesn't effect the principles that lead to a durable wheel, does it cause you to believe that he might be a good candidate for at least as many spokes as most would recommend for a tandem or loaded touring bike?
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Old 06-08-09, 05:11 PM   #10
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Wogster,
Are you aware that the OP is 450 lbs.? While this doesn't effect the principles that lead to a durable wheel, does it cause you to believe that he might be a good candidate for at least as many spokes as most would recommend for a tandem or loaded touring bike?
Yes I do, whether the bike load is a 100lb soaking wet skinny winny or an 800lb gorilla, the rules are the same. The bike is also an issue though, the rider I was posting to had a big-box store bike, spending $500 on a set of wheels for a $75 bicycle shaped object, makes no sense. The original poster for the thread has a custom built quad recumbent, with 4 wheels the load on each wheel is different then on a standard bicycle, depending on side to side load, that could be very similar to a standard bicycle with a 225lb rider. There are a lot of 225lb riders, riding with less then a 48 spoke tandem wheel. The issue to with a quad recumbent is how the wheels are set up, it may not be possible to change wheels to the wider hub needed for a tandem wheel.
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