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wheel bulding help

.Pit Steelers.

Nostradumbass
Jun 18, 2006
1,431
0
Hawaii
Ok does this sound correct? 559erd for Mavic 721 36hole laced 3cross on a Dt Swiss 440. 12mm nipples, im getting 267 for the right and 266 for the left? When i built my first wheel about a month ago some of the spokes were two short. Should i just go with like 268's for both sides just to be sure? Also when i built my lace wheel i used some cheep ass spoke wrench that deformed the nips i need something better can anyone tell me what one i need?

Thanks.

http://www.universalcycles.com/shopping/product_details.php?id=1122&category=746

spoke tools

dt calc

http://www.dtswiss.com/SpokesCalc/Calculator.aspx
 

Sghost

Turbo Monkey
Jul 13, 2008
1,045
0
NY
I didn't run your numbers through the calculator, but I would order a bag of 50 267's. You have some give on spoke lengths, and this way you'll have a few extra with a plus of a little less complications.

I'm gonna bet on your previous wheel that one side is actually off a hole on the hub. Its an easy oversight and can make some spokes a bit short, while others can still seem spot on.

Buy this wrench. It has 3 sizes so you'll have an exact fit. While I use the individual rubber handled Parks in the shop, I have a 3 way in my race kit toolbox.
http://www.universalcycles.com/shopping/product_details.php?id=8822&category=2142
http://www.universalcycles.com/shopping/product_details.php?id=8827&category=2142
 

.Pit Steelers.

Nostradumbass
Jun 18, 2006
1,431
0
Hawaii
Alright thanks sg, umm i dont think my erd is wrong i know it says that on the sicklines site but looking on the mavic site it says "ETRTO compatible size: 559 x 21c" I assume thats the erd also on my old D-521 which i think is the same thing it say's 559x21.
 

nmr8

Monkey
Apr 6, 2007
108
0
Alright thanks sg, umm i dont think my erd is wrong i know it says that on the sicklines site but looking on the mavic site it says "ETRTO compatible size: 559 x 21c" I assume thats the erd also on my old D-521 which i think is the same thing it say's 559x21.
yeah, seconded, your ERD is definitely wrong. 559 is the ISO bead seat diameter - the diameter of the tire bead in mms, which is 559 for all 26" rims and tires. the ERD - effective rim diameter - is always less.

i'd rec using the DT calculator on their website, it has tons of rim and hub data so you don't have to look up most things.
 

.Pit Steelers.

Nostradumbass
Jun 18, 2006
1,431
0
Hawaii
Alright well i just found out that the Dt calc list the 721 and says it has a 537erd, now that i have it correct (i think..) It say's 256 (bothsides), now it would be better to round up one no?
 
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Dazed

Chimp
Jan 14, 2005
7
0
Norway
Best thing to do is call mavic directly they will give you the correct ERD 1-888-GO-MAVIC


Are we doing the bet?
Mavic only talks about "spoke support diameter" (which I can understand, since it's a measurable dimension on their products), and that is 532mm for the EX721.

"ERD" on the other hand, which is the dimension used by most (all) spoke length calculators measures the distance between the top of two nipple heads, and that is about four or five millimeters more than Mavic's "spoke support diameter". That makes the ERD about 536-537mm for the EX721.

The short answer is: Use the DT Swiss spoke calculator (which uses ERD=537mm for the EX721). With the DT Calculator, it's usually better to round up than down, but never much more than 1mm.

Looks to me like you could get away with 256mm everywhere in your case.
 
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