Bicycle Mechanics - Anyone Remember The ERD for the first Mavic Cosmic rim?

I'm building a 16 hole custom phil wood track hub to a mavic cosmic rim from the 90's (don't ask). I can't find the erd, don't feel like guessing it, was going to see if any old mechanics remember the ERD or know a place that has it posted. It's litteraly the first ever cosmic rim, its silver with yellow logos that say "cosmic" and "mavic".

this is a pic of the rim in question.

http://2.bp.blogspot.com/-uFE6_fT3T7Y/TlP5iBbQsxI/AAAAAAAAAh8/9Od-jl-XRJM/s1600/photo-714492.JPG

any help is greatly appreciated.

umm, can't you just measure it? do you not have an unlaced rim?

^ every time i try measuring a rim i double and triple check to make sure i got it right and then i'm still off, what equation/method do you suggest?

I just use two spokes screwed all the way into the nipple and place them in from opposite sides measure the gap and then add that to the length of the 2 spokes.

looks to be carbon/Aluminum?

http://www.tech-mavic.com/tech-mavic/technical_manual/data/tech-mavic/uk/sources/Produits/ROUTE/Roues/CosCarbone/CarboneSpareParts.pdf

I just use two spokes screwed all the way into the nipple and place them in from opposite sides measure the gap and then add that to the length of the 2 spokes.


thats what i do but that doesn't account for spoke hole offset. ugh. looks like i gotta break out the measuring tape.


looks to be carbon/Aluminum?

http://www.tech-mavic.com/tech-mavic/technical_manual/data/tech-mavic/uk/sources/Produits/ROUTE/Roues/CosCarbone/CarboneSpareParts.pdf

^thats the info on the NEW cosmic carbon/aluminum wheelset, the one i have is waaay older, could be the same erd, could be slightly different, either way that pdf is only page 21 and it says spoke lengths are on page 34 - 35.

thats what i do but that doesn't account for spoke hole offset. ugh. looks like i gotta break out the measuring tape.

Spoke hole offset barely matters. It has the same effect as an equal change in flange to center distance, so the change in spoke length is only about 10% of the change in offset, or a few tenths of a millimeter.

That's less than the rounding and so isn't material.

If you want to factor the offset, measure the distance from the rim centerline, and add or subtract it from the flange/center distance when entering that into your calculator.

My Cosmic wheel looks exactly like yours, but it has 18 spokes. It also has a Saturn Racing Team sticker. I wonder if it's newer than yours.

Sorry to not contribute to the actual thread...

^thats the info on the NEW cosmic carbon/aluminum wheelset, the one i have is waaay older, could be the same erd, could be slightly different, either way that pdf is only page 21 and it says spoke lengths are on page 34 - 35.

that spoke length will be for their hub, not yours.
Mavic uses spoke support diameter, not ERD.

Behold!!!
http://4.bp.blogspot.com/-njXOJTKj2zM/Tl2IcAsYTuI/AAAAAAAAAik/K__cdKmBCAE/s1600/photo%2B1-724180.JPG

http://4.bp.blogspot.com/-6UpTK55iam8/Tl2IcVb3CqI/AAAAAAAAAis/sLZVxTe9-nM/s1600/photo%2B2-725555.JPG