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After 400 k starting to break spokes

Old 09-26-10, 07:08 PM
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After 400 k starting to break spokes

Finally after all these years I go out and buy myself a new Jamis Comp road bike and after 400 k. I am starting to break spokes about one every second ride and at 25 bucks a repair it is getting to expensive to ride. I has 14 gauge S/S spokes but I weigh in about 260 lb. Any thoughts about what I can do ( besides trying to lose more weight ) would be a great help
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Old 09-26-10, 08:02 PM
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Stronger wheels. It's the only way. Mosey over to the Clydesdale section of this forum for wheel advice.
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Old 09-26-10, 08:09 PM
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Are they 24 spoke wheels? When I weighed in at 220 I gave up on road bikes 20 years ago when I popped spokes every ride.
I think they were 32 spoke but I do think the wheel technology has improved greatly since then. I went to MTB's with 32 spoke
wheels and have only broken 1 spoke (lately I have popped the heads off a lot of nipples (1 every 1-2 rides) on a powertap hub with a
Stans Olympic rim, but I changed all the nipples and so far no breaks on 5 rides).

Why don't you replace them yourself, it isn't that difficult. Especially when you only have to retrue 1 spoke.
Do you ride the wheel home when it is broken, I think that can put extra stress on the remaing spokes leading to early failure
in them.

I recently bought a road bike (and I am 260+) and bought a training wheelset of 32 spoke mavic open pros on DA hubs, and have had no problem with those.
I even ventured out on the 20 spoke front 24 rear Bontragers that came with the bike, and surprisingly they have stayed true even over
some pretty crappy potholed/cracked streets.

so I suggest

1) DIY spoke replacement.
2) get some 32 spoke wheels.

Last edited by gbg; 09-26-10 at 08:26 PM.
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Old 09-26-10, 08:34 PM
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I assume it could also be a bad wheel build.

How many have you broken, and assuming you have enough data, can you make any generalizaitons:

Location of break
Front or rear (drive side spokes?)
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Old 09-27-10, 12:01 AM
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Originally Posted by Lone_rider
Finally after all these years I go out and buy myself a new Jamis Comp road bike and after 400 k. I am starting to break spokes about one every second ride and at 25 bucks a repair it is getting to expensive to ride. I has 14 gauge S/S spokes but I weigh in about 260 lb. Any thoughts about what I can do ( besides trying to lose more weight ) would be a great help

Breaking spokes that soon is an indication of a poorly-built wheel. You should probably have all the spokes replaced and the wheel built, trued, and tensioned by a good wheelbuilder.

That's assuming this is a "normal", 32 or 36-spoke wheel. If it's a boutique low-spoke-count wheel, toss it and get a properly built wheel on the bike.
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Old 09-27-10, 12:19 AM
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Originally Posted by Lone_rider
Finally after all these years I go out and buy myself a new Jamis Comp road bike and after 400 k. I am starting to break spokes about one every second ride and at 25 bucks a repair it is getting to expensive to ride. I has 14 gauge S/S spokes but I weigh in about 260 lb. Any thoughts about what I can do ( besides trying to lose more weight ) would be a great help
Your problems are poor build quality and a shop that knows little about wheels or has set you up as a repeat customer at $25 a pop (it's $40-$50 in labor to build or completely rebuild a wheel which would permanently resolve the problem). You need to either find a shop with a more skillful or honest wheel builder or learn the skills yourself. Jobst Brandt's _The Bicycle Wheel_ is good.

The issue here is that spokes fail due to fatigue, with the number of cycles they survive (about 750 per mile) dependent on average stress and the magnitude of the variation (a heavier person causes more variation).

Wheels which have not been stress relieved have parts of the elbows which were never taken past their elastic limit and therefore have high average stress. After enough cycles all those spokes (especially on the rear drive side) will fail about the same time.

Wheels with insufficient tension (especially in the rear non-drive side) can have the spokes going slack and bending with the high stress from bending creating premature failures. The low tension also allows nipples to rotate and loosen which exacerbates the problem and means the wheels don't stay true.

Your machine built wheels failed because they weren't stress relieved and may have had some spokes at excessive or insufficient tension. They would have probably survived if some one fixed that before you rode the bike.

The minimal fix is to replace all of the spokes in the side(s) which have been breaking (they all have the same number of fatigue cycles and about the same residual stress so the rest should be failing in short order) with DT or Wheelsmith 14/15 gauge double butted with brass nipples. Set drive side tension to an appropriate level like 110kgf. Tighten the non-drive side enough to center the wheel. Stress relieve. Correct any minor problems. Assuming you correctly compensated for spoke windup the wheel will stay true until you put a bend in it. The spokes will last pretty much indefinitely, through many rims (even if crashed).

Counter-intuitively, double-butted spokes which are thinner in the middle build into stronger wheels than straight-gauge spokes of the same thickness because the thinner center spans are stretchier resulting in less stress concentration at the elbows + threads and the rim can deform more before the spokes go slack leaving the rim unsupported laterally at which point it can collapse.

At 260 pounds you are exceeding the design spec of light-weight rims (under 160 pounds is a reasonable weight for bicycle racers) and are going to be more likely to bend when you run into pot-holes and other obstacles. You might consider switching to beefier rims at the same time, with reasonable spoke count (most people would recommend 36), and conventional cross-3 lacing.
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Old 09-27-10, 01:05 AM
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Originally Posted by Drew Eckhardt
Your problems are poor build quality and a shop that knows little about wheels or has set you up as a repeat customer at $25 a pop (it's $40-$50 in labor to build or completely rebuild a wheel which would permanently resolve the problem). You need to either find a shop with a more skillful or honest wheel builder or learn the skills yourself. Jobst Brandt's _The Bicycle Wheel_ is good.

The issue here is that spokes fail due to fatigue, with the number of cycles they survive (about 750 per mile) dependent on average stress and the magnitude of the variation (a heavier person causes more variation).

Wheels which have not been stress relieved have parts of the elbows which were never taken past their elastic limit and therefore have high average stress. After enough cycles all those spokes (especially on the rear drive side) will fail about the same time.

Wheels with insufficient tension (especially in the rear non-drive side) can have the spokes going slack and bending with the high stress from bending creating premature failures. The low tension also allows nipples to rotate and loosen which exacerbates the problem and means the wheels don't stay true.

Your machine built wheels failed because they weren't stress relieved and may have had some spokes at excessive or insufficient tension. They would have probably survived if some one fixed that before you rode the bike.

The minimal fix is to replace all of the spokes in the side(s) which have been breaking (they all have the same number of fatigue cycles and about the same residual stress so the rest should be failing in short order) with DT or Wheelsmith 14/15 gauge double butted with brass nipples. Set drive side tension to an appropriate level like 110kgf. Tighten the non-drive side enough to center the wheel. Stress relieve. Correct any minor problems. Assuming you correctly compensated for spoke windup the wheel will stay true until you put a bend in it. The spokes will last pretty much indefinitely, through many rims (even if crashed).

Counter-intuitively, double-butted spokes which are thinner in the middle build into stronger wheels than straight-gauge spokes of the same thickness because the thinner center spans are stretchier resulting in less stress concentration at the elbows + threads and the rim can deform more before the spokes go slack leaving the rim unsupported laterally at which point it can collapse.

At 260 pounds you are exceeding the design spec of light-weight rims (under 160 pounds is a reasonable weight for bicycle racers) and are going to be more likely to bend when you run into pot-holes and other obstacles. You might consider switching to beefier rims at the same time, with reasonable spoke count (most people would recommend 36), and conventional cross-3 lacing.
+1. Drew Eckhardt posts true wheel knowledge.
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Old 09-27-10, 08:20 AM
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260 is a lot of mass for the average 700-23/25 wheel.

1. Use a heavy duty rim like Mavic A319 with 36 holes. Straight 14G is fine to save $, but the wheel must be built by a good wheelsmith. Go with brass nipple. Avoid aluminum.

2. Use 28 or 32 mm tire. The skinny 23 mm tire normally does not provide sufficient protection from impact. Maintain pressure around 95 psi.
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Old 09-27-10, 09:11 AM
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Originally Posted by rydaddy
+1. Drew Eckhardt posts true wheel knowledge.
To put Drew's cut and paste from multiple resources in a nutshell:

Your spokes are prematurely fatigued due to improper low tensioning, therefore a rebuild with new spokes by someone who knows what they are doing and will get it right is warranted.

=8-)
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Old 09-27-10, 05:17 PM
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Thanks for all your input I am going in for surgery on Wed. so i will have some time to see about getting some new wheels built as there is a four week recovery period.
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Old 09-27-10, 10:13 PM
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Originally Posted by Lone_rider
Thanks for all your input I am going in for surgery on Wed. so i will have some time to see about getting some new wheels built as there is a four week recovery period.
Heal well.

In your downtime, read Brandt's "The Bicycle Wheel". I knew how to build wheels before I read it. Afterward, I knew what I was doing wrong, how my errors affected my wheels, and what I needed to do to correct them. Since then, I haven't broken a single undamaged spoke- not bad for someone who is 6-foot-4 and 220 pounds.
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Old 09-28-10, 06:11 PM
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Spokes only cost a couple of bucks, and a spoke wrench is about $5. It's really not a difficult job just replacing one spoke. You should learn how to do it yourself.

But this doesn't help you if you're popping spokes that frequently. Poorly built wheel is right. We have wheel builders on the forum. Maybe a post in the Clydesdale or Road forum is in order. Ask about strong wheels for heavy riders.
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Old 09-28-10, 07:08 PM
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It must be a pretty crappy build. I'm 190 and I ride a 24 spoke rear that's going strong after a full season that I built myself. It uses lightweight spokes and a light rim too. 220 may be a bit more but the wheel should still hold. Maybe you should have had the shop re-tension the wheel when you had them replace the spokes.
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