The wheelbuilding thread

Everything about building wheels, glueing tubs, etc.
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kavitator
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by kavitator

KLabs: one rim cracked becouse i get 150kg on it. But if you get on xr200 over 120kg you can see deforming of rim where nipples are. That can be seen on black rims quickly- white colour( wich was test wheelset with 140kg on ds) dont show any deformation. maby becouse of extra powdercoating (white rims are heavier too).

When DS spokes goes up with tension also NDS and this is most important as bm0p700f says.
After all if we have same components wheel with higher tension will be better in sprint ...

I am waiting to build with Bartime hubs and see the results

Has anyone info for Wheelfanatyk tensiometer and mavic R2R spokes? I dont thrust TN1 here becouse for sapim cx ray must unwind screw for 5 rounds to get correct result (For Sapim Laser or Race it is set as i get it).

Also what do you think about home calibration tool - 150kg hang scale with spoke tensioned on 120kg?
Hope you understand what i have in mind

by Weenie


bm0p700f
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by bm0p700f

I know what you mean about the XR-200 deforming (I limit the tension to 1150N max). I use a TM-1 but with CX-ray spokes I have decided now what deflection I look for and ignore the chart. I will have to get the Sapim/Horzan tenion gauge next as that looks a better bet for accurate measurment.

eric
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by eric

Kavitator- check this tensiometer calibration rig out: http://www.youtube.com/watch?feature=pl ... gsz7l1GWoI

I'm going to build one when I get a chance. The scale (I got the same one for $50 on amazon) is spec'd for +- .6kg.
I don't have a spoke threading machine and don't feel like I need one yet so I will machine a "flange" for the j-bend.

As far as more tension stiffening the wheel, sure, if the NDS spokes were loose enough to (momentarily) go slack. Beyond that if Rinard's results are correct, it should not make a difference. Of course he could have made a mistake or we could be not understanding what "slack" is in this case.

danny
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by danny

this is my new chinise 20 mm carbon rim for tubular, which is the best nipples can I use with this rims?

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WinterRider
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by WinterRider

eric wrote: Of course he could have made a mistake (Dinard) or we could be not understanding what "slack" is in this case.



Bold mine.

Seems to me much of this rim stiffness debate is verbal semantics. To definitively state the rim functions independently of the spokes is not valid IMO. The wheel is a dynamic unit.. each component part of a system interdependent of the sum of the components.

The written wheel theory pales in comparison to real world data. I find some very interesting observations on these pages... those citing actual experiences building/testing the wheel/s the reason I came to read along here.

This internet is full of bike wheel 'nonsense'. It's fine to model the workings of a bike wheel on the computer.. but some of the conclusions assumed lack the sweat spent to make these wheels DURABLE & weight efficient in the real world.

KLabs
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by KLabs

WinterRider wrote:
eric wrote: Of course he could have made a mistake (Dinard) or we could be not understanding what "slack" is in this case.

Bold mine.

Seems to me much of this rim stiffness debate is verbal semantics. To definitively state the rim functions independently of the spokes is not valid IMO. The wheel is a dynamic unit.. each component part of a system interdependent of the sum of the components.
The written wheel theory pales in comparison to real world data. I find some very interesting observations on these pages... those citing actual experiences building/testing the wheel/s the reason I came to read along here.
This internet is full of bike wheel 'nonsense'. It's fine to model the workings of a bike wheel on the computer.. but some of the conclusions assumed lack the sweat spent to make these wheels DURABLE & weight efficient in the real world.

Hi WinterRider, everything is good :-)

In kavitator's circumstance NDS spoke tension appears to have been an issue (through sprinting/pedal torque effects) and by increasing DS and NDS spoke tension this increased lateral stiffness when the wheel encountered sprinting/pedal torque effects. Unfortunately the rim could not completely handle the 140kgf DS spoke tension :-)

I believe that Bracing Angle is important to lateral stiffness and better Bracing Angle (like those of the front wheel) allow DS spoke tension to be reduced and better NDS spoke tension. 2x/3x/4x lacings provide better control of sprinting/pedal torque effects, and re the aspect of DS/NDS spoke tension, the 2:1 lacings provide nearly equal DS/NDS spoke tensions with excellent NDS Bracing Angle and as such good Lateral Stiffness. Although 2:1 lacing allows better Lateral Stiffness (through better Bracing Angle and more even DS/NDS Spoke tension), the Rim will provide the real Lateral and Radial Stiffness.

Wheel stiffness. logically, is determined by the Rim, Spokes, Spoke Lacing, and Hub. That is quite a broad statement so what does this actually mean (hope this is correct) ...

1. The Rim will provide the real Lateral and Radial Stiffness (ie a flexy rim will always be flexy regardless of spoke tension)
2. The Hub needs to support good DS/NDS Bracing Angle and Spoke Lacings that help control sprinting/pedal and Disc Brake (if used) torque effects
3. Spokes need to be stiff and strong and able to endure the tension/detension cycle which occurs as a result of torque effects
4. Rim widths and Tyres ... that's another matter :-)

eric
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by eric

If you had read the article you'd know that Rinard did not use a computer model and was not testing "rim stiffness" in isolation. He was testing an actual wheel. That's "real world".

Since that work he's become well respected in the industry. He's been a lead engineer at Trek and now at Cervelo. I would not say that means everything he's written is gospel but clearly he knows his engineering.

My "real world" experience has matched his results re: spoke tension affecting wheel stiffness. Or rather I should say it hasn't been obviously wrong, because I am just riding the wheels, not measuring their deflection under a known load as he did. Our feel is not finely calibrated and is affected by our hopes and beliefs. I.e. the "new bike effect" making someone's average speed 1 mph faster on their regular loop. I am pretty well attuned to what my bike is doing but I am not going to claim I can feel a 7 thou difference in lateral flex.

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WinterRider
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by WinterRider

"1. The Rim will provide the real Lateral and Radial Stiffness (ie a flexy rim will always be flexy regardless of spoke tension)"


I'd suggest... one can significantly increase the stiffness of a flexy rim with spokes that do not flex/stretch easily. IMO the 'real' stiffness is again a function of the entire unit.

"He was testing an actual wheel. That's "real world". (Rinard.. please excuse typo earlier)

Very true.. I included referencing the online book per wheel building.

My point.. is simply this: discussing present day real world examples I can learn something tangible from. List the components.. the conditions the outcomes were derived from.. then how that outcome is related to that SET of components. IE: what works.... and what does not... and WHY.

This in-depth discussion.. and how to cheat the scale building strong wheels... I find very informative.

Anyone ever build a triplet with the NDS tension higher than the DS?

xnavalav8r
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by xnavalav8r

I'm tired of building wheels....

bm0p700f
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by bm0p700f

A 559 ETRTO rim on a hub with a 60mm flange and 40 spoke holes, would 4x lacing have the spokes crossing the hub flange or would I need to use 3x. If this was a 622mm rim I would bet 4x would be the best option. As the ERD of the rim in 537mm I am not sure if 4x will work as well and whether 3x is a better bet. I need to order spokes for this tandam build. Any thoughts.

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kavitator
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by kavitator

Eric thx for youtube link.
Digital scale are not cheap (200 kg) , maby analog will be better. But digital looks better

Now i must find safe place to place "callibration device" :D

bm0p700f maby drawing a complete wheel and lacing is the best option

eric
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by eric

I found the same scale on amazon for $50. I needed a scale with that sort of range anyhow for a non cycling project.

You could do it with a rig that lets you hang weights from a spoke. Then you'd be limited by the accuracy of the weights, or of the scale you used to weigh them.

The good thing about the scale is that (theoretically) you could calibrate the tensiometer in 10kgf increments or whatever increments you wanted.

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kavitator
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by kavitator

With weights i see parktoll dont work good on cx rays (spring bolt must be unscrew for 5 turns)

http://kavitec.blogspot.com/2012/09/ume ... ktool.html

so scale and spoke wich can be replaced is the best. For every spoke i can get correct readings and for all tensions.

bm0p700f
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by bm0p700f

I have drawn it and 4x it is.

KLabs
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by KLabs

WinterRider wrote:"1. The Rim will provide the real Lateral and Radial Stiffness (ie a flexy rim will always be flexy regardless of spoke tension)"
I'd suggest... one can significantly increase the stiffness of a flexy rim with spokes that do not flex/stretch easily. IMO the 'real' stiffness is again a function of the entire unit.
"He was testing an actual wheel. That's "real world". (Rinard.. please excuse typo earlier)
Very true.. I included referencing the online book per wheel building.
My point.. is simply this: discussing present day real world examples I can learn something tangible from. List the components.. the conditions the outcomes were derived from.. then how that outcome is related to that SET of components. IE: what works.... and what does not... and WHY.
This in-depth discussion.. and how to cheat the scale building strong wheels... I find very informative.
Anyone ever build a triplet with the NDS tension higher than the DS?


Hi WinterRider, I believe a flexy rim's lateral and radial stiffness can be improved through spoke offset, rim offset, and rim material. Unfortunately spoke offset usually requires a box style rim and rim offset does not handle DS/NDS sideways stress/torque effects evenly. Theoretically, wider/deepish rims should be more laterally/radially stiffer but with a small weight penalty.

High spoke tension is not required with a stiff rim because a stiff rim is already laterally/radially strong, but with a flexy rim ... higher spoke tension must help in making the the rim and hub to act more like a solid wheel (ie disc wheel but one that is sprung like a continuous leaf spring). In this scenario the rim is not stiffer but the combination of Hub, Spoke/Spoke tension, and Rim is stiffer. Should one part fail then the wheel as a whole component will fail. Unfortunately, flexy rims cannot usually handle high spoke tensions and rim/spoke hole cracking usually occurs.

Theoretically, solid spoked wheels should solve this issue (ie remove Bracing Angle from the equation because they are already wide) but they usually produce heavier but stronger wheels. I am not sure why they haven't used Trussed spokes rather than solid spokes at this time. Trussed spokes should be lighter, will allow the air to pass through them and handle higher torque effects.

Logically, the following will produce NDS with higher spoke tension ...
- 3:1 spoke lacing
- Reduce the NDS offset (Bracing Angle) in relation to the DS offset
- Lengthen DS spoke length and dramatically shorten NDS spoke length while maintaining good NDS bracing angle
- WinterRider, currently the opposite is the case, so what benefits were you seeking when you asked this question :-)

by Weenie


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