The wheelbuilding thread

[pashax]

I am choosing between far sports 38 x 25 clinchers with dt240 and kinlin xr200 with powerway r 13

[Marin]

That's almost like choosing between an apple and a ticket to the movies.

[Asymptotic]

Last minute check with all you pro-wheel builders on here Lacing a BHS Sl211 to 24h carbon rim with ERD=540mm but has internal nipples.

Going 2x DS, radial NDS. Using spokepro calculator gives 257.7mm for DS spokes and 254.9mm for NDS. Now some people have said add 10mm for thread for internal nipples, this sound about right? Most spoke threads are slightly less then 10mm though from what I've measured.

So to summarise: Does DS=268mm, NDS=265mm sound accurate to you guys?

Cheers

Note: I'm waiting for the hub to arrive hence I can't take any practical measurements

[pushstart]

I haven't built any rims with internal nipples, but I would have thought that the ERD you measured (you did measure, right?) would account for any "offset". I.e. when you measure the ERD you are measuring from where the nipples sit in the rim, not the actual inner diameter of the rim material. (Many carbon rims, for example, have very thick material around the spoke holes.) Perhaps I am misunderstanding something about these rims, though.

[Asymptotic]

@pushstart, yes I did measure ERD from the edge of the rim, i.e. not from 10mm within the rim. Its a Roval 45, nothing special, spoke holes are off-set.

[eric]

With 12mm nipples, 10mm added to the spoke length sounds about right. Assuming you are using standard 12mm square nipples, inverted. I have not done an internal nipple rim yet, just visualizing it. The head of a nipple from seat to bottom of the slot is roughly 2mm deep.

Basically you want the end of the spoke to fully engage with the nipple's threads. With the nipples backwards the spokes need to be longer. If you used hex head internal nipples, those are not as long as standard nipples.

You could use your ERD measuring spokes with the nipples you want to use in the orientation you plan to use. Then you'd know. You make ERD measuring spokes by cutting two old (but straight) spokes to a known length like 250mm, threading on nipples to the proper depth, then inserting them in the rim and measuring the distance between the ends (accurately with good calipers). Add/subtract that from the total length of the two spokes as appropriate.

Pushstart is correct about where ERD is measured from.

I would think that spoke length when doing internal nipples is not as critical as when using aluminium external nipples since the nipple's strength does not depend on the spoke reinforcing the head.

[mentok]

Anyone used CNspoke MAC 424 spokes?

I just built a front wheel with them, 100kgf, with no problems. The end of the spokes were a bit ragged where they were cut, so I ground them flat and pretty. They seem to be a good deal for under $2 delivered. Certainly easier to use than lasers.

where are you getting them for <USD2 delivered?

[pushstart]

@pushstart, yes I did measure ERD from the edge of the rim, i.e. not from 10mm within the rim. Its a Roval 45, nothing special, spoke holes are off-set.

Yeah, as Eric described you want to measure ERD like this: http://www.wheelpro.co.uk/support/measuring-rim-erd.php

Measuring diameter from inner rim edge is not correct.

[Asymptotic]

Ok thanks I will re-measure ERD using the above calculator, but I'm still not seeing the relevance in accounting for the additional length needed to thread the internal nipple

[pushstart]

When you measure using that method you are actually measuring the diameter from the perspective of a spoke threaded into nipple, seated in the rim. Exactly how it will be when you build the wheels. So it doesn't matter if the nipple is internal, external, etc; you will be measuring how long the spokes need to be for that rim.

[bm0p700f]

I would wit till the internal nipples arrive and measure the ERD with the nipples threaded onto you measuring spokes. then the ERD determined will not be a guess and will be right.

[eric]

With an external nipple, if you cut the nipple in half you'd see that the threads are mostly outside the rim. Ideally the end of the spoke will be at the bottom of the slot in the head of the nipple, which is a short ways inside the rim.

With an internal nipple, all the threads are in the rim. So the spoke needs to be longer to reach them.

[Asymptotic]

Took some more measurements, the rim bed is 5mm. Spoke threads are 9mm, so eric you think just add half the length of the spoke thread i.e 4.5mm plus rim bed thickness. So the measurement of adding on 10mm which I was recommended now seems pretty accurate

[eric]

Sorry, I threw you off talking about cutting a nipple in half. I meant sectioning it lengthwise so you can see the spoke inside it.
You really need to measure it correctly not guess.

I suggest the "Measuring the ERD. The Musson "No Math" Method" from this page: http://miketechinfo.com/ERD-measuring.htm
That's how I do it. I made two 200mm spokes with the elbows cut off. Then thread on the nipples I am using until they the end of the spoke is where it should be in a built wheel. As shown on the top of that page for normal orientation the end of the spoke should be at the bottom of the slot. Since your nipples are upside down I would aim for end of the the spoke being at the top of the nipple, i.e the nipple is threaded all the way on. Then measure ERD as explained in the "no math method".

[LouisN]

Long shot here....Is it possible to true a carbon disc wheel .... ?

Louis