Need help with spokes length

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maxwkh
Posts: 22
Joined: Thu Jan 24, 2019 2:51 pm

by maxwkh

Hello fellow WWs,

This is my first wheels build and I need help on getting the right spokes length, getting paranoid because I got the wrong spokes once resulted from miscalculated ERD by 2mm extra.

I have since recalculated the ERD again, again and again and confirmed it is 590mm (ZTR Grail before the carbon version model)

The issue now is with DT Swiss calculator, it shows the spokes sizes as below:

FL: 297.4mm
FR: 298.5mm
RL: 298.6mm
RR: 298.2mm

However the suggested length are different:

FL: 295mm
FR: 296mm
RL: 297mm
RR: 296mm


Questions is:
- The number is almost 2.5mm difference in the case of FR, isn't that too much?
- Which one should I follow?
- Do I round up since usually spoke only available in even length?
- Do I need to compensate with different value for different spoke nipple?

Spoke will be Pillar 1420 - 14G with generic spoke nipple (I measured the spoke nipple length from the mistaken batch, it is 14mm with around 10mm of thread).

To peoples who have experience in wheels building, any suggestion?

Thank you for reading and your time!

P/S: I have ordered 300mm and 280mm previously - should have been 298mm, but brain mistaken 2mm with 2cm (-‸ლ), feel free to suggest ways to reuse some of it if possible.Image

by Weenie


bm0p700f
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Joined: Sat May 12, 2012 7:25 pm
Location: Glermsford, Suffolk U.K
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by bm0p700f

The problem is you cant select a pillar nipple. You selected a dt 14mm nipple and that took 2mm of the spoke lengths due to the funny way dt nipples work. Round down from the calculated lengths and go with that.

maxwkh
Posts: 22
Joined: Thu Jan 24, 2019 2:51 pm

by maxwkh

bm0p700f wrote:The problem is you cant select a pillar nipple. You selected a dt 14mm nipple and that took 2mm of the spoke lengths due to the funny way dt nipples work. Round down from the calculated lengths and go with that.
Since I can only get even spoke length, does it mean I should go with the following lengths (round down)?

FL: 296mm
FR, RL, RR: 298mm

Or it is better to go all 298mm?

Thank you.

MikeD
Posts: 225
Joined: Thu Dec 11, 2014 9:55 pm

by MikeD

Use another spoke calculator such as https://www.wheelpro.co.uk/spokecalc/

bm0p700f
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by bm0p700f

Your lengths seem to be 298mm all round. I would use spokecalc though.

alanyu
Posts: 101
Joined: Thu Jun 06, 2019 1:10 pm

by alanyu

The spoke will be pulled longer under tension, and I think that's why the suggested length are 2.5mm shorter.
plus: aerolite is worse than cx-ray under high tension, but not cheaper.

maxwkh
Posts: 22
Joined: Thu Jan 24, 2019 2:51 pm

by maxwkh

Thanks for the suggestions, this is what I got with the wheelpro's calculator and rounding method
Left
Left.PNG
Left.PNG (10.17 KiB) Viewed 70 times
Right
right.PNG
right.PNG (10.23 KiB) Viewed 70 times
According this is rounding tables, the spokes I need will be
round.PNG
Front: 298mm, 300mm
Rear: 300mm, 298mm

According to this thread I can use 2-4mm longer spokes with DSN nipple
viewtopic.php?t=149132

Since I have 300mm spokes, so I ordered the DSN nipple and will try to build one of the wheel to see if it work.

bm0p700f
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Joined: Sat May 12, 2012 7:25 pm
Location: Glermsford, Suffolk U.K
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by bm0p700f

Spokes dont stretch by 2.5mm

bm0p700f
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Location: Glermsford, Suffolk U.K
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by bm0p700f

With straight pull spokes you cant use any other spoke calculator than dt swiss currently. Go with 298mm all round with non dt swiss nipples or dt swiss suggested length with there 14mm nipples

maxwkh
Posts: 22
Joined: Thu Jan 24, 2019 2:51 pm

by maxwkh

Alright. 298mm is it then. Thank you very much.

Sent from my A0001 using Tapatalk


by Weenie


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