Weight Weenieshttp://weightweenies.starbike.com/forum/ ERD questionhttp://weightweenies.starbike.com/forum/viewtopic.php?f=113&t=125982 Page 1 of 1

 Author: Slagter [ Wed Jun 18, 2014 5:56 pm ] Post subject: ERD question Hi guysI need a little help to figure out the exact ERD. The manufacturer says 548 mm ERD. I´ve cut two spokes to an exact length of 200 mm each. Well maybe 200,5 mm each:When I insert the spokes in opposite spoke holes in the rim, the spokes are 151,5 mm apart from each other on both front and rear:Rear rimFront rimThat should give me:200,5 + 200,5 + 151,5 = 552,5The only thing I´m worried about is, did I measure the spokes correct? I can´t figure out if I´m supposed to measure the spoke from the top of the nipple? or from where the nipple goes through the rim. In other words, do I have to measure the spokes length with or without the nipple head. I´ve read the section in Rogner Mussons book over and over again, but can´t find the answer.

 Author: Weenie [ Wed Jun 18, 2014 5:56 pm ] Post subject: ERD question

 Author: Orfitinho [ Wed Jun 18, 2014 6:25 pm ] Post subject: Re: ERD question http://www.wheelpro.co.uk/spokecalc/ --> rimsRoger Musson wrote:Take two spokes cut down to 200mm. Glue on a nipple so that the top of the spoke is flush with the bottom of the slot in the nipple.

 Author: Slagter [ Wed Jun 18, 2014 6:49 pm ] Post subject: Re: ERD question Exactly. But what I´m a little bit concerned about is, that different nipples have different size nippleheads, which will make Mussons advice inaccurate, because the measurement of the ERD will depend on the type of nipple, you are using... Or am I missing the point??

 Author: vinceflynow [ Wed Jun 18, 2014 7:05 pm ] Post subject: Re: ERD question I use Mussons spokecalc and his book to build my wheels. I've found that his way of measuring ERD to be overly complicated. There is an easier way:Insert a spoke through the rim, and thread it into a nipple. You don't need to cut the spoke. Insert another spoke onto the rim on the opposite side of the first spoke, and thread it into a nipple. Use a rubber band, and join the two spoke ends. Measure the total length from one end of the spoke, where it enter the nipple, to the opposite end of the other spoke (L). Measure length of the nipple (N), and add the values to get ERD.L = length from one end of spoke/nipple interface to other endN = nipple lengthERD = L + 2N

 Author: pam [ Wed Jun 18, 2014 7:09 pm ] Post subject: Re: ERD question That sounds right. ERD as used by the Sheldon Brown and DT Swiss calculator etc. should be exactly the diameter made by the very end of the threaded tips of the spokes once they are installed. What type of nipples and washers used affects how far you want the spokes to reach.