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Wheel building question

Old 05-28-21, 04:44 PM
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Ti473
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Wheel building question

Hello Folks,
I am sourcing out parts for a rear wheel build, and I am pretty confused about the length of the spokes that I need. I used several spoke calculators and they all spit out different numbers, some are way off (see pictures below). What Gives? What do I actually need?
The wheel will be a Crest CB7 laced on a DT Swiss 350 classic with 12mm aluminum nipples, and nipple washers, 3x lacing.

Here's the numbers:

Hub:
  • Hub Drilling: 32
  • Center to Flange, Right: 20.2
  • Spoke Interface: J-Bend
  • Center to Flange, Left: 33
  • Flange Diameter, Right: 46
  • Flange Diameter, Left: 46
  • Rear Axle: 12mm Thru x 142mm
Rim is a 600mm ERD and spokes will be sapim race J-bend
Any help is appreciated. Thanks!



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Old 05-28-21, 05:28 PM
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Bill Kapaun
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I get the same numbers on SpokeCalc as the top w/ 2.6mm dia. spoke holes.
I would just get 292 for both, assuming the ERD is correct.
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Old 05-28-21, 05:39 PM
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CliffordK
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If at all possible, I like to get the rims and hubs in front of me so that I can do the measurements myself.

That way, I can also measure to the top of the nipples, and include any washers if I want.
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Old 05-28-21, 05:54 PM
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Ti473
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yeah I think 292 seems good, I don't know why sapim's calculator is so off...
Are washers recommended? and should I add anything for them? This is on a Carbon Crest CB7, they don't mention anything about washers on their site, but I'm sure they can't hurt right?
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Old 05-28-21, 06:07 PM
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I think the Sapim is off because they want the internal diameter of the rim and rim thickness, not the ERD, which is essentially the internal diameter of the rim plus 2x the rim thickness. I think that is a confusing. Measuring ERD is simpler.

Edit: I tried plugging your numbers in using the ERD for internal rim diameter and zero for rim thickness. I thought it would work, but I got 294/296 spoke lengths. Closer, but not close enough. I'm at a loss.

Last edited by gearbasher; 05-28-21 at 06:26 PM.
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Old 05-28-21, 06:29 PM
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I trust most of the info on the wheel building calculators but always measure the ERD myself. Don't forget to add in double the thickness of one nipple washer If you use them. I like the Sapim spokes and their Polyax nipples.
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Old 05-28-21, 07:26 PM
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I would strongly recommend brass nipples rather than aluminum.
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Old 05-29-21, 08:27 AM
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pro lock nipples are very hard to deal with. they add torsional stress and strain on the spokes. they have loctite like paste in them.
i would only use pro lock if dealing with 24x wheels and i would only use them on the non drive side flange spokes/nipples.

brass nipples are much better and you could use a beeswax based homebrew lube if you expect accidental large loads that would have otherwise had your down spoke momentarily lose tension (nipple able to unscrew at that point). that being one way a wheel goes out of true, gradually...

beeswax is a good thing, you could go with something better... just saying that beeswas can be a bit stiff once the spoke has momentarily lost tension so it can prevent nipple unscrew.

and lubricate the eyelets/nipple interface with a proper grease for the application. not saying what that would be - because lotsa folks can pop out and disagree on what would work best. i'll let you to trial and error. but the most important thing is this: grease is essential on the nipple/eyelets interface and not greases are equal. i tried with dura ace grease - which is calcium - and it is utter crap btw.

Last edited by adipe; 05-29-21 at 08:33 AM.
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Old 05-29-21, 08:47 AM
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Originally Posted by Bill Kapaun View Post
I would just get 292 for both, assuming the ERD is correct.
i'd say go with 290 DS (right flange) and 292 NDS (left flange) and use butted spokes on the NDS. if you have good skills and knowledge you could go with quite thin spokes on the NDS (i can handle 1.5mm) but if you are a rookie and don't know how to deal with torsional stress/strain then go with 1.8mm. for the the NDS that is. i would go with 1.8mm DS and 1.5-1.65mm NDS but would recommend 2mm (plain) and 1.8mm (plain/butted) gauge spokes. there are some 1.8mm plain spokes which need nipples for that thread size.

as the computed numbers i got were 291.68 left 290.65 right from this site:
https://spokecalculator.qbp.com/spok...ator/calculate
i have entered in the exact numbers i saw on the OP post. did not bother with what 350 hub classic would really mean and rim too.

there's also more spoke elastic elongation on thin spokes which means that you should be more careful to balance radial runout with spoke tension variance. but you should do that first working on the DS flange at medium tension with the NDS spokes having a tiny bit of tension, just enough to adjust lateral true (to be able to properly adjust radial) - meaning DS spokes having 89.999 degrees angle from the rim to the hub at that moderate tension. after that stage is done then you should not touch DS nipples but work on NDS alone while building tension etc. that would suppose you have the eyelets bedding in with the nipples uniformly. one more reason professional wheel builders readjust DS (loosening NDS all the way again) before finishing the wheel.

Last edited by adipe; 05-29-21 at 09:04 AM.
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Old 05-29-21, 11:58 AM
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If FBinNY still posted here, he'd quip that a man with two watches can never be sure what time it is.

With aluminum nipples and nipple washers, it'll be better to err on the side of too long than too short.
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Old 05-29-21, 03:24 PM
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Originally Posted by Bill Kapaun View Post
I get the same numbers on SpokeCalc as the top w/ 2.6mm dia. spoke holes.
I would just get 292 for both, assuming the ERD is correct.
I got the same on SpokeCalc. I would always recommend double butted spokes for reliability.
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Old 05-30-21, 12:35 AM
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be sure to mash the spokes down with the palm of your hand where they come out of the hub to get the bend right.
when they bend those spokes, they tend to creep back and lose a few degrees.
or they were never bent far enuff in the first place, or both.
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