Building up a pair of 20” disc wheels for my sons new bike and getting mixed results from spoke length calculators.

I’m running rims with 396mm ERD, Novatec front and Hope evo rear.

Wheelpro and Edd/Leonard differ by about 10mm

So rather confused!
Thanks

On quick way could be to use the ERD you already know, minus the hub spoke hole radius and allow for spoke engage to into the rim bed (basically add some for spoke insertion into spoke nipple) and get a rough number. This might allow you to guess which one, if either are right?

Have you got the same number of crossings on each calculator?

Ok thanks. So (396-58)/2=169mm (do I get points for showing my working?)

Same number of crossings (3), although I’m undecided whether just to go for 2 anyway.

Nearly 20mm difference on the 2 cross options

Are you entering the hub dimensions manually or just selecting the hub from a list?

Entering them manually. I’ve checked what I’m entering but have possibly balls’d something up!

Bugger…yup…my mistake! One calculators flange is another’s hub diameter.

🤦🏼‍♂️🤦🏼‍♂️🤦🏼‍♂️

You ain’t seen me right….