# Confused about which way I need to round my spoke length.



## Ventura Roubaix (Oct 10, 2009)

Ok , I'm working on building a rear wheel, Its a H Plus Son Archtype, with a Dt Swiss 350 road hub. The erd as I measured it using Roger Musson method in his e-book is 592. I have used 4 different spoke calculator's. 
1. Prowheelbuilder.com, nds=288.6, ds=287.2 
2. Dt Swiss, nds=288.6, ds=287.2
3. WheelPro(Musson site), nds= 288.4, ds=287
4. Bikeschool.com, nds=288.6, ds=287.2

My main question is about rounding the ds number, according to Musson you round up or down up to 1mm to the nearest number, there seems to be a consensus among the calculators, so the ds number is 287, do I need to round down to 286 or round up to 288?


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## dcgriz (Feb 13, 2011)

Theoretically, it should not matter. Practically, I would go up to 288mm if I could not get the 287mm.


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## Ventura Roubaix (Oct 10, 2009)

Thanks, dcgriz. I also was wondering if it was unusual for the spoke length for both sides to be the same length considering dish of the wheel. I was going to round down on the nds to 288.


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## Ventura Roubaix (Oct 10, 2009)

After triple checking my rim erd, using Roger Musson and Mike T 1st method on his site, I have change it from 592 to 593. So now my spoke length's are, nds=289.1, ds=287.7. The question now is do I round the nds up to 290 or down to 288?, I will round the ds up to 288


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## Mike T. (Feb 3, 2004)

Always use the rule-of-thumb for spoke number rounding - "up or down a maximum of +/- 1mm from the calculated length to the available spoke length" (some suppliers only stock odd number lengths and some only stock even number lengths).

The only time I would break this rule is if I was using thin center Laser or Revs - If the calculation was (let's say) 289.1 or 289.2 I'd go down to 288 and not up to 290 if just even lengths were for sale.

But that's me. OOMV.

But if November Dave posts and he contradicts me, go with his opinion as he builds more wheels in a morning than I do in a year.


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## Ventura Roubaix (Oct 10, 2009)

Mike T. said:


> Always use the rule-of-thumb for spoke number rounding - "up or down a maximum of +/- 1mm from the calculated length to the available spoke length" (some suppliers only stock odd number lengths and some only stock even number lengths).
> 
> The only time I would break this rule is if I was using thin center Laser or Revs - If the calculation was (let's say) 289.1 or 289.2 I'd go down to 288 and not up to 290 if just even lengths were for sale.
> 
> ...


Thanks Mike T's, I have found a online site(Wheels Manufacturing) that sells in odd and even sizes, So i will go nds=289.1 rounded to 289, ds=287.7 rounded to 288, does this look good to you.


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## dcgriz (Feb 13, 2011)

For the most accurate results make sure that you measure *all* components in accordance to the instructions given by the particular spoke length calculator you are using because results will otherwise differ.
Your 289.1 to 289 and 287.7 to 288 look fine to me assuming you measured the hub flanges as Musson is showing to do since it seems you are using his calculator.


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## Manning (Jul 8, 2010)

I've been rounding down on the short spokes (high tension side), and up on the long spokes (low tension side). If lacing radial heads out, round down. Maybe I've been getting lucky, but it's been working out perfectly.


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## Mike T. (Feb 3, 2004)

Manning said:


> I've been rounding down on the short spokes (high tension side), and up on the long spokes (low tension side). If lacing radial heads out, round down. Maybe I've been getting lucky, but it's been working out perfectly.


Those are interesting ideas. I wonder what comment someone with the experience of November Dave will have on this.


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## blackfrancois (Jul 6, 2016)

i'm terrible at measuring erd, so i don't do it. i've been lucky with online erd databases.

i verify my hub measurements using online databases to see if i'm the ballpark. i always use my own hub numbers. then round down all calculated spoke lengths. 

and finally, don't worry about it, because it always works out.


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## Mike T. (Feb 3, 2004)

blackfrancois said:


> i'm terrible at measuring erd, so i don't do it. i've been lucky with online erd databases.


One day there's a good chance you'll get bitten in the arse. It could have happened to me last year but I found a bad ERD within 5 minutes of opening the box. It was 5mm out. The number that was given was the nipple seat diameter. I pointed the mistake out to the maker and they said woops we screwed up. Within hours the figure had changed on one place on their site but not on their .pdf. 

Some rims get their spec changed and I wonder how many rim databases or retailers' sites catch the change - and how many make the change.



> i verify my hub measurements using online databases to see if i'm the ballpark. i always use my own hub numbers.


And that's the least important measurement by far. You could almost eyeball hub data and be close enough.


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## MudSnow (Sep 18, 2015)

Usually round down. Being 1mm short won't cause any problems, but being 1mm long can result in the nipples bottoming out on the threads and binding, or having to force the nipples.


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## Mike T. (Feb 3, 2004)

MudSnow said:


> Always round down. Being 1mm short won't cause any problems, but being 1mm long can result in the nipples bottoming out on the threads and binding, or having to force the nipples.


So what you're saying is this -

If the calculated length was 281.9 and the spokes were only available in even number lengths, you would go down to 280 and not up to 282? Wouldn't that put the end of the spoke right at the neck of the nipple?


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## MudSnow (Sep 18, 2015)

Okay, not always, that's an extreme example. But it's safer to round down 1.5 than up 1.0 when spokes are only available in even sizes.


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## Mike T. (Feb 3, 2004)

MudSnow said:


> Okay, not always, that's an extreme example. But it's safer to round down 1.5 than up 1.0 when spokes are only available in even sizes.


'Scuse me for being terminally picky with my example but you were the one who wrote "Always round down". There are a lot of newby wheelbuilders who use the info left behind on this forum and they don't need advice that might get them bitten in the arse.

I don't ever remember anything but "+/-1mm" being given as proven advice around here.


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## November Dave (Dec 7, 2011)

Mike T. said:


> Always use the rule-of-thumb for spoke number rounding - "up or down a maximum of +/- 1mm from the calculated length to the available spoke length" (some suppliers only stock odd number lengths and some only stock even number lengths).
> 
> The only time I would break this rule is if I was using thin center Laser or Revs - If the calculation was (let's say) 289.1 or 289.2 I'd go down to 288 and not up to 290 if just even lengths were for sale.
> 
> ...


This is what I'd say, yes. We use a Phil Wood spoke machine (best money ever spent) so size to .5mm resolution, but that's possibly a distinction without a difference. If you can only get odd or even lengths, Mike's advice is good. I'd include CX Rays with the default "round down" group. 

As soon as we get the page built we'll be selling spokes in 1mm increments to give people access to more precise lengths.


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## MudSnow (Sep 18, 2015)

November Dave said:


> I'd include CX Rays with the default "round down" group.


Yes, I build with mostly CX-Rays and they definitely stretch. I guess I generally round up not more than 0.5mm and round down as much as 1.5mm.


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## Mike T. (Feb 3, 2004)

November Dave said:


> This is what I'd say, yes. We use a Phil Wood spoke machine (best money ever spent) so size to .5mm resolution, but that's possibly a distinction without a difference. If you can only get odd or even lengths, Mike's advice is good. I'd include CX Rays with the default "round down" group.
> As soon as we get the page built we'll be selling spokes in 1mm increments to give people access to more precise lengths.


You're in a different position to us home wheelbuilders of course Dave. It's not possible to justify a spoke cutter/thread roller for the wheel numbers most of us churn out. But I get most of my spokes from importer Thorsten and he will cut if necessary. I have never found it necessary and that's why I preach the "+/-1mm" thingamajig. He has cut for me but only when he didn't have the needed length in stock at the time.

Yes with CX-Rays and Laser I stretch (is that a pun?) the rule a bit but most newbs don't build with those spokes from the get-go (at least they don't if they follow my site's warnings).

Edit. Ok this bit just clicked in - *"we'll be selling spokes"*. You gonna be selling all wheel parts?


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## Lombard (May 8, 2014)

blackfrancois said:


> i'm terrible at measuring erd, so i don't do it. i've been lucky with online erd databases.


Russian Roulette!! I was about to go lazy like you with my first build and trust manufacturers databases. My bike shop mechanic as well as most builders on this forum warned against this. Yes, you will get away with this maybe 9 out of 10 times. That one time the number is wrong will lead you to much frustration, extra expense, wasted time and lots of cursing. Do you really want to take the chance? As the saying goes in the carpentry trade "Measure twice, cut once".



Mike T. said:


> I don't ever remember anything but "+/-1mm" being given as proven advice around here.


Exactly. 1mm too long will not bottom out in the nipple.

Now here's the trick question. If calculations come out to say 289.0 and the choices are only evens....288 and 290. Which way would you go? Roger Musson is OK with either choice and I doubt it really matters. Does anybody here have a definite choice?


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## Mike T. (Feb 3, 2004)

Lombard said:


> Now here's the trick question. If calculations come out to say 289.0 and the choices are only evens....288 and 290. Which way would you go? Roger Musson is OK with either choice and I doubt it really matters. Does anybody here have a definite choice?


With me it would default to what Mud said - "round down" but I'd have to add this bit "if the spokes were skinny Laser (or Revs) or CX-Ray". But that's me.

I've only come unstuck with this advice once in living memory (my wife will claim that's 5 minutes tops) and a DS set was too long and a NDS set was too *&^%$* short. Arrgghh. I dug out my meager stash of spokes and finally went with 2x/1x on the rear when I untended to do 2x/2x. I rebuilt that rear wheel about 6 times in 2 days. Arrgghh x2.


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## dcgriz (Feb 13, 2011)

Lombard said:


> Now here's the trick question. If calculations come out to say 289.0 and the choices are only evens....288 and 290. Which way would you go? Roger Musson is OK with either choice and I doubt it really matters. Does anybody here have a definite choice?


The first thing I do is check my measurements and predominantly re-verify/remeasure the rim ERD to make sure that the average I took is correct. If this checks out then I round-up for the following two reasons:
a) I dont like to have the spokes start tightening too early when building and
b) In the event that I screwed up my measurements (even after I re-verified; has not happened yet) I could adjust for shorter needed spokes by changing my standard Sapim nipples to DT and salvage the spokes. Murphy's law response basically. Have not had to put this to use yet but it makes sense to me since nipples are much cheaper than spokes


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## Lombard (May 8, 2014)

dcgriz said:


> The first thing I do is check my measurements and predominantly re-verify/remeasure the rim ERD to make sure that the average I took is correct. If this checks out then I round-up for the following two reasons:
> a) I dont like to have the spokes start tightening too early when building and
> b) In the event that I screwed up my measurements (even after I re-verified; has not happened yet) I could adjust for shorter needed spokes by changing my standard Sapim nipples to DT and salvage the spokes. Murphy's law response basically. Have not had to put this to use yet but it makes sense to me since nipples are much cheaper than spokes



Hmmm. Well since I use DT spokes and nipples, I guess that means I should in theory round-down? That way if they are too short, I could change to Sapim nipples?


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## dcgriz (Feb 13, 2011)

Lombard said:


> Hmmm. Well since I use DT spokes and nipples, I guess that means I should in theory round-down? That way if they are too short, I could change to Sapim nipples?


That would be a logical deduction if you used Sapim nipples to measure the rim ERD and the Wheelpro calculator to size the spokes.


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## MudSnow (Sep 18, 2015)

There are 10-12mm of thread in the nipples, so if the spokes are 1mm short, it won't matter. But you can get 14mm nipples. So I round down.


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## Lombard (May 8, 2014)

MudSnow said:


> There are 10-12mm of thread in the nipples, so if the spokes are 1mm short, it won't matter. But you can get 14mm nipples. So I round down.


Hmmm. Now there's a simple inexpensive solution!


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## November Dave (Dec 7, 2011)

Mike T. said:


> Edit. Ok this bit just clicked in - *"we'll be selling spokes"*. You gonna be selling all wheel parts?


Not all, but some. Not trying to get into an already crowded market of selling commodity stuff, but where we can provide unique access to a product, or add value to the selling of a product, or something along those lines, we will.

On the other topic, I may be exposing some stupidity here, but I've never gotten the deal with varying nipple lengths. I want the spoke end to wind up in the same precise position relative to the rim every time - call it +/- 2.5mm inside the spoke bed of the rim. To me, longer nipples are useful when you have a rim with a thick spoke bed, like carbons, or rims with very sharp v points, where a 12mm doesn't give enough access to the wrench flats. 

I'm aware of the nipples that have a longer "back end" like the Squorx (?) nipples from DT, and Sapim has an equivalent. I think American Classic actually invented the concept. And those give more tolerance to making spokes slightly too long. But on a regular nipple, to me a spoke that's too short with a 12mm nipple is still going to be too short with a 14mm nipple. What am I missing there?


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## Lombard (May 8, 2014)

November Dave said:


> Not all, but some. Not trying to get into an already crowded market of selling commodity stuff, but where we can provide unique access to a product, or add value to the selling of a product, or something along those lines, we will.
> 
> On the other topic, I may be exposing some stupidity here, but I've never gotten the deal with varying nipple lengths. I want the spoke end to wind up in the same precise position relative to the rim every time - call it +/- 2.5mm inside the spoke bed of the rim. To me, longer nipples are useful when you have a rim with a thick spoke bed, like carbons, or rims with very sharp v points, where a 12mm doesn't give enough access to the wrench flats.
> 
> I'm aware of the nipples that have a longer "back end" like the Squorx (?) nipples from DT, and Sapim has an equivalent. I think American Classic actually invented the concept. And those give more tolerance to making spokes slightly too long. But on a regular nipple, to me a spoke that's too short with a 12mm nipple is still going to be too short with a 14mm nipple. What am I missing there?



Good explanation Dave! Brain fart on my part. Yes, if a spoke thread won't make it to the head of the 12mm nipple, it won't make it to the head of the 14mm nipple - DUH! :idea:


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## Mike T. (Feb 3, 2004)

November Dave said:


> On the other topic, I may be exposing some stupidity here, but I've never gotten the deal with varying nipple lengths. I want the spoke end to wind up in the same precise position relative to the rim every time - call it +/- 2.5mm inside the spoke bed of the rim. To me, longer nipples are useful when you have a rim with a thick spoke bed, like carbons, or rims with very sharp v points, where a 12mm doesn't give enough access to the wrench flat.................to me a spoke that's too short with a 12mm nipple is still going to be too short with a 14mm nipple. What am I missing there?


I don't think you're missing anything. I don't have enough experience, especially fudging up incorrect spoke lengths with longer nipples, to contribute to earlier comments on this. To me it's dead simple - the spoke ends up at the bottom of the slot or it's a cock-up. Something went "wrong" - my measuring or the calculator's behind the scenes workings (I measure all spokes when I get 'em - some have been wrong). Oh sure even me with some OCD can live with spokes within the "+/-1mm" - leaving spokes at the top of the slot or 1/2 way down the nipple head. But I wouldn't juggle nipples to fudge up a deviation from this. I'd re-order the right length, and have in the past.

Yes I agree - longer nipples are for thicker nipple beds. End of.


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## Lombard (May 8, 2014)

Mike T. said:


> .....(I measure all spokes when I get 'em - some have been wrong).....


Eeeegad! All I did was gather them and make sure they were all the same length. So you're more OCD than I for sure!

But in both my builds, when the wheel was finished, the spoke came up at least to the top of the nipple head and never "bottomed out". Or should I say "topped out"?


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## Mike T. (Feb 3, 2004)

Lombard said:


> Eeeegad! All I did was gather them and make sure they were all the same length. So you're more OCD than I for sure!


I've been caught 2x with incorrect spoke lengths in the last two years. One time, it was like a handful of spokes had been thrown back in the wrong bin. I had 12 of one length and 14 of another. So now I take 5 mins with the spoke ruler and measure each one. That saves me wasting hours.

You'd think I'd build a gizzmo to hang all of them from wouldn't ya? Then that way I just have to measure one.


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## Lombard (May 8, 2014)

Mike T. said:


> I've been caught 2x with incorrect spoke lengths in the last two years. One time, it was like a handful of spokes had been thrown back in the wrong bin. I had 12 of one length and 14 of another. So now I take 5 mins with the spoke ruler and measure each one. That saves me wasting hours.
> 
> You'd think I'd build a gizzmo to hang all of them from wouldn't ya? Then that way I just have to measure one.



OK, I see why for you it's an issue because you build so many wheels. I take the right sizes right out of the boxes to use. Both my builds used 288 rear DS and 290 rear NDS and front. Hard to mix up.


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## Mike T. (Feb 3, 2004)

Lombard said:


> OK, I see why for you it's an issue because you build so many wheels.


No I don't and I've never said that I do. Lots of people assume that because of my site. I said recently that November Dave will build more wheels in a morning than I do in a year - about 2 sets for myself, and only that many as I like to try & test a few rims. I don't *ever* want to build wheels for other people. My schick is motivating people to start building their own. Heck I don't give 'em *all* the info either so they have to be curious and search elsewhere (aka Roger's e-book).



> I take the right sizes right out of the boxes to use. Both my builds used 288 rear DS and 290 rear NDS and front. Hard to mix up.


So you assume all the spokes in the box are the right size eh? You have more faith than I do.


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## zucchiniboy (Apr 10, 2014)

If you were in a "round up" vs "round down" conundrum, couldn't you add nipple washers to adjust so it's closer to what the ideal length is? i.e., say a measurement called for 289mm, but you only had access to even lengths, you could add nipple washers (effectively increasing the ERD) to those spokes and go with 290mm, right?


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## Mike T. (Feb 3, 2004)

zucchiniboy said:


> If you were in a "round up" vs "round down" conundrum, couldn't you add nipple washers to adjust so it's closer to what the ideal length is? i.e., say a measurement called for 289mm, but you only had access to even lengths, you could add nipple washers (effectively increasing the ERD) to those spokes and go with 290mm, right?


I've done that before as they add 1.4mm to the ERD. But it becomes a moot exercise as I normally use nipple washer and I use then on my dummy spokes for measuring ERD so they're already factored in. I guess I could use a 2nd set of washers eh?


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## dcgriz (Feb 13, 2011)

November Dave said:


> I'm aware of the nipples that have a longer "back end" like the Squorx (?) nipples from DT, and Sapim has an equivalent. I think American Classic actually invented the concept. And those give more tolerance to making spokes slightly too long. *But on a regular nipple, to me a spoke that's too short with a 12mm nipple is still going to be too short with a 14mm nipple. What am I missing there*?


Dave,

That's not necessarily true. 

Let's put it this way, a spoke that is 1mm too short with a Sapim 12mm nipple will also be 1mm too short with either a 14mm or 16mm Sapim nipple.
To the contrary, a spoke that is 1mm too short with a Sapim 12mm nipple will be just right with a DT 14mm nipple and 1mm too long with a DT 16mm nipple.

The reason for this is the nipple thread length. Sapim maintains constant thread length in all of their nipples so the spoke length good for the 12mm is also good with the 14 and the 16mm. 
DT varies the thread length incrementally by 1mm from the 12mm to the 16mm per 2mm of added nipple length. So the spokes for the 14mm and the 16mm are 1mm and 2mm shorter than the spokes for the 12mm. This is based on the ERD measurements being done with 12mm nipples.

Roger Musson's ebook shows a cut-out view of the DT nipple thread length for each nipple size and very nicely further explains all this.

Needless to say, this is not a reason to use anything but 12mm nipples, unless the rim bed needs it of course. It is just another piece of info that may salvage a bunch of spokes if Mr. Murphy knocks on the door.


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## Lombard (May 8, 2014)

Mike T. said:


> No I don't and I've never said that I do. Lots of people assume that because of my site. I said recently that November Dave will build more wheels in a morning than I do in a year - about 2 sets for myself, and only that many as I like to try & test a few rims. I don't *ever* want to build wheels for other people. My schick is motivating people to start building their own. Heck I don't give 'em *all* the info either so they have to be curious and search elsewhere (aka Roger's e-book).


Understood. My point was that you have built way more wheels than I have. From your previous post, it sounds like you have an inventory of quite a few different sizes of spokes. So being meticulous and categorizing them is important to avoid mix ups.



Mike T. said:


> So you assume all the spokes in the box are the right size eh? You have more faith than I do.


As I said before, I took all the spokes out of the box and gathered them together to verify for myself that they were all the same length. Maybe I should have measured them to be thorough. I "got away" (yes, I know you hate that term ) with not measuring the spokes and trusted my shop and the manufacturer that they labeled the boxes correctly. But you are correct of course, to be better safe than sorry in order to save a potential waste of time and avoid lots of cursing. Next time!


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## Lombard (May 8, 2014)

dcgriz said:


> The reason for this is the nipple thread length. Sapim maintains constant thread length in all of their nipples so the spoke length good for the 12mm is also good with the 14 and the 16mm.
> DT varies the thread length incrementally by 1mm from the 12mm to the 16mm per 2mm of added nipple length. So the spokes for the 14mm and the 16mm are 1mm and 2mm shorter than the spokes for the 12mm. This is based on the ERD measurements being done with 12mm nipples.



This is certainly an interesting observation. Me thinks that if the thread length increases with nipple length and spoke threads don't also increase, a longer nipple will result in less of the spoke thread getting into the nipple head, resulting in a weaker connection between spoke and nipple.


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## dcgriz (Feb 13, 2011)

Lombard said:


> This is certainly an interesting observation. Me thinks that if the thread length increases with nipple length and spoke threads don't also increase, a longer nipple will result in less of the spoke thread getting into the nipple head, resulting in a weaker connection between spoke and nipple.



This is the ramification of using the DT 16mm. Their 14mm is not as bad because it ends up with what could be argued as adequate support for the nipple shoulders. The 12mm obviously offers the most support. Its also interesting to note that the DT spoke calculator automatically adjusts the spoke length to account for 14mm and 16mm nipples.

Anyway, I think this whole DT nipple thread length thing is more confusing than arguably helpful but, as I said before, there may be a case where it could be useful to know. If nothing else file it away in your data bank. That's all.


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## Mike T. (Feb 3, 2004)

Lombard said:


> From your previous post, it sounds like you have an inventory of quite a few different sizes of spokes.


Not at all. I have a couple of other sets that were sent to me incorrectly and it's too expensive to ship them back so they just send out a new batch. So I had a couple of sets laying around.



> being meticulous and categorizing them is important to avoid mix ups


Tell that to the people at the other end. It was their people who must have thrown some spokes in the wrong bin. But that's just an assumption on my part. They could have arrived at the distributor from the maker already mixed up. But the bottom line is the same - trust no-one but yourself using your own eyes.


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## sheepherder (Mar 11, 2012)

MudSnow said:


> Yes, I build with mostly CX-Rays and they definitely stretch. I guess I generally round up not more than 0.5mm and round down as much as 1.5mm.





Mike T. said:


> Yes with CX-Rays and Laser I stretch (is that a pun?) the rule a bit but most newbs don't build with those spokes from the get-go (at least they don't if they follow my site's warnings).
> 
> Edit. Ok this bit just clicked in - *"we'll be selling spokes"*. You gonna be selling all wheel parts?





November Dave said:


> This is what I'd say, yes. We use a Phil Wood spoke machine (best money ever spent) so size to .5mm resolution, but that's possibly a distinction without a difference. If you can only get odd or even lengths, Mike's advice is good. I'd include CX Rays with the default "round down" group.
> 
> As soon as we get the page built we'll be selling spokes in 1mm increments to give people access to more precise lengths.


I'm building with cx rays, 24/28 with dura ace hubs, hed c2 rims (erd592) 2 cross front and back

The problem I'm having is most sites calculate my front spoke length at 287.7 and rear at 281.7 and right around 284.

However when I use the wheelpro site it brings these number down significantly, front would be 286.6 which means I would go down to 286. Why is there such a big difference between the measurements?

It also changes what length I would need in the rear. What site should I follow? Or can I just round everything down with cxrays? If the other sites are correct though I would be rounding down 1.7mm for the front


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## bikerjulio (Jan 19, 2010)

sheepherder said:


> I'm building with cx rays, 24/28 with dura ace hubs, hed c2 rims (erd592) 2 cross front and back
> 
> The problem I'm having is most sites calculate my front spoke length at 277.7 and rear at 281.7 and right around 284.
> 
> ...


What DA hub dimensions are you using? There's more than one DA hub.

You should not be seeing that kind of difference. It's a flag that you are doing something wrong.


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## sheepherder (Mar 11, 2012)

bikerjulio said:


> What DA hub dimensions are you using? There's more than one DA hub.
> 
> You should not be seeing that kind of difference. It's a flag that you are doing something wrong.


Sorry using DA 9000. The front has Flange diameter of 38 and 34 flange to center. Don't remember the exact rear but I think it was something like left fd 44 centre 37 and right fd 45 to centre 17. 

It could be wheelpro is the only site taking into account I am using cxray. It asks for spoke diameter and per there instructions I use 1.5 for cxray


I noticed BHS has a surcharge for custom sizes. Any issues with that?

Thanks


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## bikerjulio (Jan 19, 2010)

sheepherder said:


> Sorry using DA 9000. The front has Flange diameter of 38 and 34 flange to center. Don't remember the exact rear but I think it was something like left fd 44 centre 37 and right fd 45 to centre 17.
> 
> It could be wheelpro is the only site taking into account I am using cxray. It asks for spoke diameter and per there instructions I use 1.5 for cxray
> 
> ...


I did the front and came up with 286.8. Perhaps you had dimensions transposed.

I always use the BHS calculator https://www.wheelpro.co.uk/spokecalc/


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## Lombard (May 8, 2014)

sheepherder said:


> I'm building with cx rays, 24/28 with dura ace hubs, hed c2 rims (erd592) 2 cross front and back
> 
> The problem I'm having is most sites calculate my front spoke length at 277.7 and rear at 281.7 and right around 284.
> 
> ...


Yikes! These discrepancies are a red flag that you should do your own measurements the hard way. Put everything else away, get Roger Musson's awesome e-book:

https://www.wheelpro.co.uk/wheelbuilding/book.php

...and follow his directions to the letter on how to calculate spoke lengths. As Mike T. wisely said, trust nobody except yourself......unless you like building your wheelset twice and spending twice as much $$ on spokes.


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## sheepherder (Mar 11, 2012)

bikerjulio said:


> I did the front and came up with 286.8. Perhaps you had dimensions transposed.
> 
> I always use the BHS calculator https://www.wheelpro.co.uk/spokecalc/





Lombard said:


> Yikes! These discrepancies are a red flag that you should do your own measurements the hard way. Put everything else away, get Roger Musson's awesome e-book:
> 
> https://www.wheelpro.co.uk/wheelbuilding/book.php
> 
> ...and follow his directions to the letter on how to calculate spoke lengths. As Mike T. wisely said, trust nobody except yourself......unless you like building your wheelset twice and spending twice as much $$ on spokes.


Shoot, sorry for the typo above. I meant they are 0.9mm apart. entering the same numbers in https://www.wheelpro.co.uk/spokecalc/ give me 0.9mm less then all other sites on the web like dtswiss, #1 Wheel Building SPOKE CALCULATOR Now Online | PROWHEELBUILDER, and a few others. I used 5 in total.

Also the rear right is also coming up 0.9mm less on https://www.wheelpro.co.uk/spokecalc/


Is https://www.wheelpro.co.uk/spokecalc/ taking into account the stretch? If I go with these numbers should I still round down because I am using cxrays or should I round up to make it closer to the other sites?


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## bikerjulio (Jan 19, 2010)

sheepherder said:


> Shoot, sorry for the typo above. I meant they are 0.9mm apart. entering the same numbers in https://www.wheelpro.co.uk/spokecalc/ give me 0.9mm less then all other sites on the web like dtswiss, #1 Wheel Building SPOKE CALCULATOR Now Online | PROWHEELBUILDER, and a few others. I used 5 in total.
> 
> Also the rear right is also coming up 0.9mm less on https://www.wheelpro.co.uk/spokecalc/
> 
> ...


The calculator takes stretch into account. BHS note that comes with the calculator says to round up.

I stopped using the DT Swiss one a long time ago. It uses some dimensions like nipple, that are proprietary to them.


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## No Time Toulouse (Sep 7, 2016)

blackfrancois said:


> i'm terrible at measuring erd, so i don't do it. i've been lucky with online erd databases..../QUOTE]
> 
> So was I......until I built a wheel with a Campy Strada tubular rim. Did you know that there are at least 3 different ERØ's for 3 different versions all called "Camagnolo Strada"? I own 2 of them...


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## roger-m (Jul 1, 2015)

sheepherder said:


> Is https://www.wheelpro.co.uk/spokecalc/ taking into account the stretch? If I go with these numbers should I still round down because I am using cxrays or should I round up to make it closer to the other sites?


Right on the front page of the calculator it says...



> This is the new Wheelpro spoke length calculator. It uses engineering elongation equations to fine tune the results from the standard spoke length formula to give very accurate spoke lengths. For use with stainless steel spokes.
> 
> *Round the fractional spoke lengths up*. For more information please read the help guide.


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## wojtek.l.wojciech (Dec 20, 2021)

Hello, 
Rear 
nds: 290.4
ds: 289.6
according to wheelpro.co.uk calculator.
Will I be ok with nds 291 and ds290?


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## Lombard (May 8, 2014)

wojtek.l.wojciech said:


> Hello,
> Rear
> nds: 290.4
> ds: 289.6
> ...


That will be ideal, though it's hard to find odd length spokes. They are usually only available in even lengths which would put you at 290 for both. I'm guessing this is either an offset or a disc brake wheel. If not, your measurements are off.


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## wojtek.l.wojciech (Dec 20, 2021)

Thanks for your reply, Lombard. Yes, this is an offset rim. Luckily, I can order 291mm DT swiss competition from a german bike shop.


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## wojtek.l.wojciech (Dec 20, 2021)

And also a disc brake, yup. MTB


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## No Time Toulouse (Sep 7, 2016)

wojtek.l.wojciech said:


> Hello,
> Rear
> nds: 290.4
> ds: 289.6
> ...


And, after 4 years, this thread can now be retired (at least until the next newbie dredges a years-old thread from the depths..)


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## Lombard (May 8, 2014)

No Time Toulouse said:


> And, after 4 years, this thread can now be retired (at least until the next newbie dredges a years-old thread from the depths..)


@No Time Toulouse , can't you ever contribute anything positive? Who cares if it's an old thread?


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## PBL450 (Apr 12, 2014)

Someone found the thread looking for a solution to a question about their wheels. They got the answer! It worked! RBR helped someone out in the real world, that’s what the site is here for!! That’s not a thread dredge out of the blue, I mean those do happen too... But this Google leading someone to RBR. That’s good!


Sent from my iPad using Tapatalk


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