Cycling and bicycle discussion forums. 
   Click here to join our community Log in to access your Control Panel  


Go Back   > >

Bicycle Mechanics Broken bottom bracket? Tacoed wheel? If you're having problems with your bicycle, or just need help fixing a flat, drop in here for the latest on bicycle mechanics & bicycle maintenance.

User Tag List

Reply
 
Thread Tools Search this Thread
Old 08-23-11, 01:04 PM   #1
geoluv
greasy hermit
Thread Starter
 
geoluv's Avatar
 
Join Date: May 2009
Location: nyc
Bikes:
Posts: 80
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
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.



any help is greatly appreciated.
geoluv is offline   Reply With Quote
Old 08-23-11, 01:28 PM   #2
motobecane69
Banned.
 
Join Date: Mar 2011
Bikes:
Posts: 1,100
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
umm, can't you just measure it? do you not have an unlaced rim?
motobecane69 is offline   Reply With Quote
Old 08-23-11, 04:53 PM   #3
geoluv
greasy hermit
Thread Starter
 
geoluv's Avatar
 
Join Date: May 2009
Location: nyc
Bikes:
Posts: 80
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
^ 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?
geoluv is offline   Reply With Quote
Old 08-23-11, 05:15 PM   #4
motobecane69
Banned.
 
Join Date: Mar 2011
Bikes:
Posts: 1,100
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
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.
motobecane69 is offline   Reply With Quote
Old 08-23-11, 05:59 PM   #5
Soil_Sampler
A little North of Hell
 
Join Date: Mar 2006
Bikes:
Posts: 4,811
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 20 Post(s)
Cosmic

looks to be carbon/Aluminum?

http://www.tech-mavic.com/tech-mavic...SpareParts.pdf
Soil_Sampler is offline   Reply With Quote
Old 08-23-11, 08:06 PM   #6
geoluv
greasy hermit
Thread Starter
 
geoluv's Avatar
 
Join Date: May 2009
Location: nyc
Bikes:
Posts: 80
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by motobecane69 View Post
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.

Quote:
Originally Posted by Soil_Sampler View Post
^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.

Last edited by geoluv; 08-23-11 at 08:09 PM.
geoluv is offline   Reply With Quote
Old 08-23-11, 09:52 PM   #7
FBinNY 
Senior Member
 
Join Date: Apr 2009
Location: New Rochelle, NY
Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
Posts: 29,919
Mentioned: 8 Post(s)
Tagged: 0 Thread(s)
Quoted: 348 Post(s)
Quote:
Originally Posted by geoluv View Post
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.
__________________
FB
Chain-L site

An ounce of diagnosis is worth a pound of cure.

“Never argue with an idiot. He will only bring you down to his level and beat you with experience.”, George Carlin

“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN

WARNING, I'm from New York. Thin skinned people should maintain safe distance.
FBinNY is offline   Reply With Quote
Old 08-24-11, 01:04 PM   #8
FastJake
Constant tinkerer
 
FastJake's Avatar
 
Join Date: May 2010
Location: Madison, Wisconsin
Bikes:
Posts: 7,577
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
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...
FastJake is offline   Reply With Quote
Old 08-24-11, 05:23 PM   #9
Soil_Sampler
A little North of Hell
 
Join Date: Mar 2006
Bikes:
Posts: 4,811
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 20 Post(s)
erd

Quote:
Originally Posted by geoluv View Post
^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.
Soil_Sampler is offline   Reply With Quote
Old 08-30-11, 07:13 PM   #10
geoluv
greasy hermit
Thread Starter
 
geoluv's Avatar
 
Join Date: May 2009
Location: nyc
Bikes:
Posts: 80
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Behold!!!


geoluv is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -6. The time now is 05:30 PM.