Help...spokes breaking
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Help...spokes breaking
Riding home from work, I hear a ping, something hit the ground, and then by rear wheel starts rubbing on the fender. 1/2 mile to home so I grit my teeth an finish ride.
Sure enoght spoke broke....on drive side. Replace the spoke and start truing wheel (this is a new thinng for me, but I have the sheldon brown print out and am going to build a wheel this week also..so this was a good start)
As I am adjusting the wheel....another spoke breaks...drive side
The hub is a deore, the rim Sun CR18 and the spokes are straight gauge stainless (bought wheelset, don't remember spoke brand)
So my questions:
Should I just relieve all the spokes tension and start over?
Is the probable cuase overtension? or what?
sound like I should buy a tool I hadn't planned on...the tensionmeter
Any thoughts and suggestions
thanks
PS it is 32 hole rim, I'm a clyde (250) and only have about a hundred milles on the wheels...running a 28 mm tire
Sure enoght spoke broke....on drive side. Replace the spoke and start truing wheel (this is a new thinng for me, but I have the sheldon brown print out and am going to build a wheel this week also..so this was a good start)
As I am adjusting the wheel....another spoke breaks...drive side
The hub is a deore, the rim Sun CR18 and the spokes are straight gauge stainless (bought wheelset, don't remember spoke brand)
So my questions:
Should I just relieve all the spokes tension and start over?
Is the probable cuase overtension? or what?
sound like I should buy a tool I hadn't planned on...the tensionmeter
Any thoughts and suggestions
thanks
PS it is 32 hole rim, I'm a clyde (250) and only have about a hundred milles on the wheels...running a 28 mm tire
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"Should I just relieve all the spokes tension and start over?"
Probably a good idea, especially since you intend to build your own.
"Is the probable cuase overtension? or what?"
Probably not overtension unless the spokes are very poor quality. Spokes most often break from undertension. Loose spokes flex more than tight spokes. The flex causes metal fatigue and the spokes usually break in the "J" bend at the hub.
"sound like I should buy a tool I hadn't planned on...the tensionmeter"
I think the Park tension meter at about $60 is an excellent investment. Be careful to release the meter onto the spokes gradually. A quick release causes elastic rebound and an inaccurate reading.
Al
Probably a good idea, especially since you intend to build your own.
"Is the probable cuase overtension? or what?"
Probably not overtension unless the spokes are very poor quality. Spokes most often break from undertension. Loose spokes flex more than tight spokes. The flex causes metal fatigue and the spokes usually break in the "J" bend at the hub.
"sound like I should buy a tool I hadn't planned on...the tensionmeter"
I think the Park tension meter at about $60 is an excellent investment. Be careful to release the meter onto the spokes gradually. A quick release causes elastic rebound and an inaccurate reading.
Al
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The answer to your question is counterintuitive. Your spokes are likely too loose.
You can't tension a spoke enough on a wheel to have it break from over-tension.
Spokes typically break from fatigue. As the spokes roll to the bottom they go slack then get tight again until the next time around. If the spokes are too loose then the tension will go to zero when at the bottom. The cycle of tight-loose-tight-loose... is what causes the metal to fatigue. Your wheel either was built with defective spokes (unlikely) or was insufficiently tensioned (much more likely).
If you continue to break spokes, then replace all of them on the drive side at least. Then tighten them as tight as practical. Actually the purchase (or loan) of a tensiometer would help you get a feel for what the proper tension should feel like. If you have a well built wheel of similar size around, you can pull together two adjacent spokes to get a tactile feel of what proper tension feels like. Another trick is to pluck a spoke and try to tune the tone of the sound to a similar pitch.
You can't tension a spoke enough on a wheel to have it break from over-tension.
Spokes typically break from fatigue. As the spokes roll to the bottom they go slack then get tight again until the next time around. If the spokes are too loose then the tension will go to zero when at the bottom. The cycle of tight-loose-tight-loose... is what causes the metal to fatigue. Your wheel either was built with defective spokes (unlikely) or was insufficiently tensioned (much more likely).
If you continue to break spokes, then replace all of them on the drive side at least. Then tighten them as tight as practical. Actually the purchase (or loan) of a tensiometer would help you get a feel for what the proper tension should feel like. If you have a well built wheel of similar size around, you can pull together two adjacent spokes to get a tactile feel of what proper tension feels like. Another trick is to pluck a spoke and try to tune the tone of the sound to a similar pitch.
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If you're building your own, I'd recommend a 36 spoke setup! Much stronger. I don't know of any off hand, but there are 36-hole rims that are run in TANDEM bikes that should do you fine.
With pre-built wheelsets (machine-made?) it's always a good idea to check tension on the spokes, because you can never count on fine points of quality unless you do it yourself! Stress the wheel to set the spokes and get out the tensiometer if you want to be sure it's right. If you were 160lbs you'd have a lot more room for error, but you're putting a lot of stress on your wheels so they need to be right.
One thing you CAN'T rely on for spoke tension is the torque on the spoke wrench because there may be a bit of mashed thread or corrosion or sand or lube that will dramatically change how "tight" it feels.
Keep in mind that if a rim is bent, the spokes will NEED to be slightly different tension to pull the wheel back straight and round.
Good call on the 28mm tire, I think most people running 700x23s would be pleasantly surprised if they went up a size or two and gave up their pro-tour airs. I've found that 700x23 gives me a lot more grief in terms of ride harshness and not much more speed.
With pre-built wheelsets (machine-made?) it's always a good idea to check tension on the spokes, because you can never count on fine points of quality unless you do it yourself! Stress the wheel to set the spokes and get out the tensiometer if you want to be sure it's right. If you were 160lbs you'd have a lot more room for error, but you're putting a lot of stress on your wheels so they need to be right.
One thing you CAN'T rely on for spoke tension is the torque on the spoke wrench because there may be a bit of mashed thread or corrosion or sand or lube that will dramatically change how "tight" it feels.
Keep in mind that if a rim is bent, the spokes will NEED to be slightly different tension to pull the wheel back straight and round.
Good call on the 28mm tire, I think most people running 700x23s would be pleasantly surprised if they went up a size or two and gave up their pro-tour airs. I've found that 700x23 gives me a lot more grief in terms of ride harshness and not much more speed.
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I kind of doubt that your spoke breakage was due to overall inadequate tension. If that were the case, I'd expect the non-drive spokes to break first. Uneven tension may be an issue.
If it was my wheel, I d loosen all of the spokes until there was one thread showing. Then I'd gradually bring the wheel up to tension starting with 1/2 turn and eventually 1/4 turn on each spoke. When I had the wheel adequately tensioned, I'd true it by tightening and loosening opposing pairs of spokes an equal amount.
If it was my wheel, I d loosen all of the spokes until there was one thread showing. Then I'd gradually bring the wheel up to tension starting with 1/2 turn and eventually 1/4 turn on each spoke. When I had the wheel adequately tensioned, I'd true it by tightening and loosening opposing pairs of spokes an equal amount.
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Off topic...mine even but can't resist with credit to
steve Katzman : There are 10 kinds of people ... those that understand binary and those that don't.
and hexidecimal is even better.....I'm 33!
steve Katzman : There are 10 kinds of people ... those that understand binary and those that don't.
and hexidecimal is even better.....I'm 33!