New to wheelbuilding, questions about spoke calc

SkidMarked · Jul 11, 2022

I'm building a 29" rear wheel. Rim: WTB KOM light i30, 32 hole. Hub: DT Swiss 350 12x148 (shimano microspline), 6 bolt disc. I'm planning on a 2 cross lacing pattern.

I have taken my own measurements of the ERD and hub dimension as well as done some online research. I have used 3 different calculators, and I have a few discrepancies.

	kstoerz.com	spokecalculator.qbp.com	proWheelbuilder	Manual measurement/calc
ERD	606	605.7	605	605
L - Ctr to Flange	36.6	36.3	37	37.8
R - Ctr to Flang	23.3	23	23	23
L - Circle Diameter	58	60	58	58.2
R - Circle Diameter	52	49.8	52	52
Spoke length - L	284.3	283.3	284.3	283.9
Spoke length - R	284.9	285.2	284.8	284.3

So, kstoerz and proWheelbuilder are really close. I can't seem to find the factory specs for DT swiss hubs. My hub is not brand new and I think the dimension changed in ~2021.
Suggestions on how to resolve the dicrepances? ... or just go with the kstoerz values? Since I am less than 1 mm difference between spokes, does it even make sense to order two different sizes?

meschenbruch · Jul 11, 2022

Have you tried the DT Swiss calculator? Seeing as you have a DT hub you can just choose it from the drop downs and manually put in the ERD from the rim. I would double check the way you've measured the ERD for the DT calculator, it measures from the slot of the spoke nipple.

Spoke calculator - DT Swiss

spokes-calculator.dtswiss.com

What kind of spokes and nipple are you going to use? Need to also consider stretch from the spokes and different gauges/buttings will stretch at slightly different rates.

SkidMarked · Jul 12, 2022

Planning on DT swiss spokes(2.0) and DT swiss 12 mm nipples

Thorjensen · Jul 11, 2022

I just ran your own messured ERD at 605 and DT350 Boost 6-Bolt pre-2021 hub dimensions through my everyday go-to calculator from wheelpro.co.uk and I got these lengths.
If I were to build a rear wheel using that hub, rim, 2X, a DB 1.8 spoke, 12mm DT* nippel or a 12-16mm Sapim nippel i'd go with 284 DS and NDS.

* If you go with a 14mm DT nippel you need a 1mm shorter spoke a 2mm shorter spoke if using a 16mm nippel.

233946 · Jul 12, 2022

Just to add a couple of points:

Make sure you are measuring ERD with the nipples you will be using and spoke threaded to the bottom of the slot in the spoke nipple. This is important as different nipples will give you different ERDs (all Sapim nipples will give the same, but DT Swiss change based on the length).
I use the wheelpro UK calculator and have always had it be spot on. Based on Thorgenson's calculation, assuming your ERD is correct, I would use 284 all around.

SkidMarked · Jul 12, 2022

Thank you for all the helpful comments. I had forgotten that DT swiss has a calculator tool.

233946 · Jul 13, 2022

Ping Mikesee, he likely has the spokes and nipples.

SkidMarked · Jul 13, 2022

Looks like I can find Sapim spokes. I still plan to use DT swiss 12 mm nipples. Any appreciable difference in the length measurement between DT Swiss and Sapim spokes?

Thorjensen · Jul 13, 2022

I primarely build with Sapim spokes AND nipples.
Why??? Well Sapim only makes spokes, nipples and washers so they suit my nerd gene the best.

I would use Sapim Race spokes that would be like using DT Competition with the same 2-1.8-2.
Dont go with the even thinner spokes as a new builder as you need to take more care not twisting the the spokes while giving tension.

If using Sapim nipples you can use 12, 14 or 16mm without that effecting your spoke length.

New to wheelbuilding, questions about spoke calc

Spoke calculator - DT Swiss

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