Front Wheel Spoke Tension

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BoSoxYacht
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Joined: Thu Oct 01, 2009 8:39 pm

by BoSoxYacht

TheKaiser wrote:I am sure that many of you have already seen them, but for those who haven't, here is the data:

Article and explanation: http://sheldonbrown.com/rinard/wheel/index.htm

Table of measurements: http://www.sheldonbrown.com/rinard/wheel/data.htm

Sugarkane cited a real world example above: "I built some shop 50mm wheels early on that we're up around the 109kgf range ( I was using the parks meter ) and had a few local NRS guys ride them at the local crit circuit ( a rough corse with 20+ corners ). They all told me they were skittish through corners..
Once I backed them up to 85kg and equalised the tension.. They were night and day better.
" It would be interesting to know if, at 85kg, those spokes were going totally slack in the instances of subjectively smoother ride. If so, it could most certainly explain the smoothed out ride, although to the detriment of the wheels longevity. With a deep section carbon rim, it might resist collapse better than shallow aluminum, as the rim has more intrinsic strength and stiffness, but you will still be getting long term fatigue problems on the spokes due to the cyclical tensioning/detensioning. Unfortunately, I am not aware of a way to measure and record tension changes in a dynamic environment like this, which is what would be required to confirm the status of the spokes at those moments.

Depending on where your baseline setup is, you may be able to achieve a similar effect by using fewer and thinner spokes, but still tensioning them properly, providing a better ride smoothness/longevity balance.

Most of this makes sense, but not about spokes going slack at 85 KgF. NDS spokes are usually lower than that, but don't normally fail. NDS spoke are usually the ones that fail, but not when at 85KgF.

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sugarkane
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by sugarkane

No way at 85kgf and 100% tension ratio ( front wheel has equal tension on both sides ) that your are getting 0 tension at all ( slack spokes ). That occurs in a rear wheel on the non drive side when the spokes have less than 40 kgf. And it's pretty much always followed by frequent broken non drive side spokes. I use the 85kgf as a base line with deep dish carbon. Alloy rims I aim at around 95kgf a little higher if the rider is large. Same on the carbon more tension for larger riders. I also ( don't tell sheldon :roll: ) radial lace the non drive side of race wheels for the bigger/stronger guys as it adds around 15% to the non drive side tensions.

In more exciting news.... I recently rebuilt one of Ligeros triplet hubs to a modern carbon rim.. The results were impressive. Lots of bracing angle and a tension ratio pushing 80%.. Let's just say I'm talking to some one about doing a run on triplet hubs. And have lined up supply of straight drilled Belguim rims and offset drilled carbon from the guys I work with.

Sorry I had to seperate the drive and non drive sides of the tension graph as the have very different spoke counts
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DartanianX
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by DartanianX

lol - 20+ Corners.

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ergott
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by ergott

sugarkane wrote:I know the consensus is amongst wheelbuilders that tension doesn't effect the way a wheel rides but that consensus is held buy guys who don't race bikes or like radial lacing....


It's not a consensus, it's science and the properties of steel.

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