Spoke length check

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fossala
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Spoke length check

Postby fossala » 13 Nov 2019, 4:16pm

Can someone check my numbers for spokes before I order?

Rim ERD 548

Rear is 24h 2 cross
Spoke drilling diameter – 42 mm
Hub center – flange center – 32.0 mm

Front is 20h radial
Spoke drilling diameter – 34 mm
Hub center – flange center – 37 mm

My numbers come out as
Rear 264.85mm
Front 258.54mm

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Mick F
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Re: Spoke length check

Postby Mick F » 13 Nov 2019, 4:26pm

The same figures come out using https://leonard.io/edd/
Mick F. Cornwall

Jamesh
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Re: Spoke length check

Postby Jamesh » 13 Nov 2019, 4:34pm

Out of interest what hubs and rims?

Cheers James

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fossala
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Re: Spoke length check

Postby fossala » 13 Nov 2019, 4:42pm

Front is a black Mack road
https://mackhubs.com/hubs/road/road-front/

Rear is a black Mack LF 130mm single fixed
https://mackhubs.com/hubs/track/low-flange-rear/

Rims are 46mm deep 28mm wide light bicycle carbon.
https://www.lightbicycle.com/Road-bicyc ... lable.html

Spokes will be Salim CX ray in either black or sliver. Thinking silver with black brass spokes.

Should save me about 500g on my current wheelset and be more aero. I'm having a go at LEJOGLE in 7 days on my fixed bike next June.

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fossala
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Re: Spoke length check

Postby fossala » 13 Nov 2019, 4:47pm

Mick F wrote:The same figures come out using https://leonard.io/edd/

Any idea what nipple length calculaors default to? I normally go for 14mm.

Brucey
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Re: Spoke length check

Postby Brucey » 13 Nov 2019, 5:42pm

I would suggest that you measure the rims before ordering the spokes and that when you measure you use the nipples that you want to use, and have the spoke sitting in the nipple the way you want it too. Skinny spokes like x-rays stretch elastically by ~0.5mm, which you can allow for if you want. I normally measure with the spoke finishing at the bottom of the nipple slot, which means the spoke usually finishes within the slot depth or flush with the top of the nipple in the built wheel.

I'd normally use 12mm nipples but with carbon rims 14mm or 16mm might be better because they are usually thicker in the base of the rim.

cheers
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NATURAL ANKLING
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Re: Spoke length check

Postby NATURAL ANKLING » 13 Nov 2019, 8:29pm

Hi,
As said measure rims, also measure the hubs...................................or at least measure the hubs before you assemble wheel.

I only made that mistake once, the tables for hubs are produced by who?
IIRC the general public?
NA Thinks Just End 2 End Return + Bivvy
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fossala
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Re: Spoke length check

Postby fossala » 13 Nov 2019, 8:39pm

NATURAL ANKLING wrote:Hi,
As said measure rims, also measure the hubs...................................or at least measure the hubs before you assemble wheel.

I only made that mistake once, the tables for hubs are produced by who?
IIRC the general public?

The hubs measurements are from his website but I'll hold off ordering the spokes until I have the hubs and rims in hand which should be about a week.

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Mick F
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Re: Spoke length check

Postby Mick F » 14 Nov 2019, 8:43am

fossala wrote:
Mick F wrote:The same figures come out using https://leonard.io/edd/

Any idea what nipple length calculaors default to? I normally go for 14mm.
I go for the nipples that come with the spokes.
Without measuring them, I wouldn't know what length they are.

Always buy your hubs and rims, and measure them yourself.
Use a couple or three spoke length calculators and make sure they agree, then round up the calculated lengths.
Mick F. Cornwall

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NATURAL ANKLING
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Re: Spoke length check

Postby NATURAL ANKLING » 14 Nov 2019, 12:22pm

Hi,
Even when you measure all the stuff yourself and round up by half a millimetre, even when you can choose by the millimetre the length.
You still have a problem with occasional nipples well spoke will be either slightly too long or slightly too short.
Ideally you want them slightly longer, But then run risk of protruding spokes.
Building the same wheels over and over Is not so bad you know how to make adjustments next time, But for your amateur homebuilder building a particular set up for the first time it's always going to be a bit of a compromise.

Some of us like to be a perfectionist, I do, but you just keep questioning the way you done it, especially when some of the experts start adding another level of stress relieving/tweaking to their well trusted methods.
So it's a constant mind game, Did I get that right, Was the tension correct, Will I break a spoke later.
Not thinking like that means it's possible that you might still kid yourself that you know what you're doing.
NA Thinks Just End 2 End Return + Bivvy
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Please forgive the poor Grammar I blame it on my mobile and phat thinkers.

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interestedcp
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Re: Spoke length check

Postby interestedcp » 14 Nov 2019, 1:15pm

fossala wrote:Can someone check my numbers for spokes before I order?

Rim ERD 548


The above ERD is extremely likely to be wrong, because the manufacturer says "548mm (not including nipple head dimension)".

The problem with supplying a correct ERD number is that ERD depends on the dimensions of the nipple and that may vary from brand to brand. In other words, a rims ERD isn't something one can measure using the rim alone.

So the above 548 mm number isn't actually the rim ERD. To get the right ERD with this rim, you have to measure it by yourself.
Here is a terse description on how; https://leonard.io/edd/howtomeasure It doesn't specify that the nipples used may change the measurement.
Or get Roger Musson's excellent wheel building book for a good method for measuring ERD if you don't already know.
--
Regards

Brucey
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Re: Spoke length check

Postby Brucey » 14 Nov 2019, 1:23pm

on the basis of that description I'd describe the supplied measurement as NSD not ERD where NSD is Nipple Seat Diameter.

NSD + 3mm ~ ERD

is a good approximation but there is no substitute for measuring your own rims.

cheers
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interestedcp
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Re: Spoke length check

Postby interestedcp » 14 Nov 2019, 1:42pm

fossala wrote:
Mick F wrote:The same figures come out using https://leonard.io/edd/

Any idea what nipple length calculaors default to? I normally go for 14mm.


The most common ones assume a standard 12 mm nipple, since both Sapim and DT Swiss and probably many others informally have standardized this as the cheap, standard "brass" nipple size with comparable dimensions.

The DT Swiss spoke calculator subtract 1 mm from the calculated spoke length when using 14 mm DT Swiss nipples instead of 12 mm nipples. But AFAIK, Sapim 14 mm "brass" nipples are identical to 12 mm nipples when it comes to spoke length/ERD calculation. They just have a longer shank.
--
Regards

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NATURAL ANKLING
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Re: Spoke length check

Postby NATURAL ANKLING » 14 Nov 2019, 3:19pm

Hi,
NATURAL ANKLING wrote:You still have a problem with occasional nipples, well spoke will be either slightly too long or slightly too short.

Just to clarify, I was meaning that, on one wheel some of all spoke ends end up long or short to the average, I am not sure what causes this it may well be rims or hubs.
There will be tolerances on the hole positions on the hubs?
Or it maybe something to do with the rivets?
Might be just cheapo rims I use :P
NA Thinks Just End 2 End Return + Bivvy
You'll Still Find Me At The Top Of A Hill
Please forgive the poor Grammar I blame it on my mobile and phat thinkers.