Velocity Dyad ERD=598.5?
 

I am planning to build a front 622 wheel with a Velocity Dyad rim. Ideally I would measure (and I will), but I would like to order the rim/spokes/nipples/hub in same order. Most sites list ERD=596 (including Velocity), but FreeSpoke (ksoterz.com, 2013) gives 598.5 for the US version, with a specific statement that it changed from the Australian version of 596.

This seems to be a common rim. I would be grateful if someone knows the number and could verify. Thank you.

ERD is the diameter at the spoke head seat in the rim. ETRTO # is the tire bead seat.,
ERD is an input in spoke length calculations.. hub spoke hole diameter is the other end..
Know nothing of these specific variations from alternate competing sources..

The ACTUAL number is what you measure yourself. I've observed so much online variance and in the actual product... only trusting now what I find myself.

Simplest method: lay rim on flat surface.. stretch METAL tape inside from valve hole to seam.. 32nd of inch is .032.. mm is .039.
Do same at 90 degrees from valve.. do all over again till confident you have correct in inches.. 700c usually ~ 23-24".

Take your inch measurement and divide by .03937 (1 mm) gives IRD. I call inside rim... IRD... ---->ADD 8mm normally for rim thickness, nip head and spoke stretch. IRD plus 8mm gives ERD.

Rinard's Spokecalc shows 596. I have used his charts with no problems.

Rohloff manual shows a way to measure your self.

you put in 2 spokes of measured length, on opposite sides of the rim like 12:00 & 6:00
and with a caliper you measure the distance between the 2 spoke hook ends...

those 3 numbers = the ERD

I just built a wheel today with a Dyad. Measured it at 597. But measure yours to be sure. I have seen variances.
Edit to add. Actually, my measurement confirms the spec from Velocity site. https://www.velocityusa.com/product/rims/dyad-622

Thank you very much!

No it is NOT!

Effective Rim Diameter is the distance from the end of one spoke to the end of the other spoke at 180 degrees in and already built and functional bicycle wheel.

...hence why many builders will use spokes of known length with nipples set and a caliper to emulate where the ends of their spokes will be for a wheel they are trying to build.

=8-|

Indeed! I thread the measuring spokes to the bottom of the slot in the nipple. I guess between rim compression and spoke stretch, the spoke may gain 1-2 mm in length and be flush with nipple end? However, from what I've read, ideally, the spoke thread should insert into the nipple sufficiently far so that the spoke thread just begins to deform the inner nipple thread, so perhaps 1mm out the end of nipple.