Dura-Ace straight-pull hub wheel building

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F45
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by F45

I used the depth gauge on my calipers.

by Weenie


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PeterKim
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by PeterKim

6th picture updated
PeterKim wrote:
Sun Dec 23, 2018 3:33 am
Rim ERD: 541mm

The following images will contain the rest of the necessary dimensions <--- Hopefully
1st image: Flange Distance Left, Flange Distance Right on both front and rear hubs
2ed image: Pitch Circle Left & Right on the front hub
3rd image: Pitch Circle Left on the rear hub
4th image: Pitch Circle Right on the rear hub
5th image: Distance Between Spoke Holes Right on the rear hub
6th image: Offset Spoke Hole Right on the rear hub

Thank You :D
joejack951 wrote:
Sat Dec 22, 2018 9:21 pm
If a CAD model is needed to assess the spoke length, shoot me the dimensions of everything (rim and hub, all relevant dimensions) and I can draw it up fairly quickly. I have some models set up for the task having built some oddball wheels myself (like a ISO 254mm rim with 16 holes laced to a 32 hole hub, converting my son's CNOC 14 to a BMX freewheel hub from a coaster brake hub).
Attachments
IMG_0497 2.jpg

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ergott
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by ergott

I already posted a link to the calcular you're looking for.

https://www.wheelpro.co.uk/spokecalc/

PeterKim
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Joined: Mon Mar 26, 2018 11:09 am

by PeterKim

I was able to use this for the front wheel spoke calculation and the rear wheel non-drive side calculation. But I am still unable to calculate the drive side spoke length because of the hub is 2:1/triplet lacing hub. I saw some of your previous posts, and it is pretty clear that I am not getting something. I will be grateful if you can tell me how to use this calculator for my particular situation.
ergott wrote:
Fri Dec 28, 2018 4:11 pm
I already posted a link to the calcular you're looking for.

https://www.wheelpro.co.uk/spokecalc/

bm0p700f
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by bm0p700f

That calculator ergot does not work for straight pull given the "paired" nature of the spoke mounts 2x won't give the right lengths.

I can guess the lengths too. For all the straight pull build I have done with 2x lacing to get epic calc to spit out the right lengths I have had to use fractional crossing like 2.5 for carbon Ti X hub road hubs. Or 2.1 for miche swr. For straight pull hubs as well as paired spoked the crossing number is not the actual crossing number.

A drawing is the only way to do it unless you want to do a bit if trig. The normal triplet calculation method assume traditional flange. The result will be wrong for a straight pull hub.

bm0p700f
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by bm0p700f

Actually the trig method has a problem, there is an angle in the spoke length formula that for traditional flanged hubs can be determined from the crossing but for straight pull builds can't because of the spoke placement from the hub so your back to a drawing to get the angle.

joejack951
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by joejack951

I will try and draw this up today. Been busy with the holidays and such.

joejack951
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by joejack951

Assuming all dimensions I've been given are correct, I am getting the following from my CAD model:

Laced 3X:
Rear NDS - 253.5mm
Rear DS leading - 274.7mm
Rear DS trailing - 274.4mm

Laced 2X (angle of spokes leaving hub looks horrible so I would not suggest this):
Rear DS leading - 261.2mm
Rear DS trailing - 260.9mm

If you need to revise any hub measurements, let me know. At this point recalculations are quite simple.

joejack951
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by joejack951

PeterKim wrote:
Sat Dec 29, 2018 12:43 am
I was able to use this for the front wheel spoke calculation and the rear wheel non-drive side calculation. But I am still unable to calculate the drive side spoke length because of the hub is 2:1/triplet lacing hub. I saw some of your previous posts, and it is pretty clear that I am not getting something. I will be grateful if you can tell me how to use this calculator for my particular situation.
When do you plan on building these wheels?

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