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probably down to how the ERD is measured… some include the all length of a 12 mm nipple, some only include a 10 mm portion of it. I belong to the latter camp, so my measured ERD could be up to 4 mm shorter than others. Thing is, using my method I already tend to get spoke which use all the thread available, so I don’t know how others using the other method can avoid having spokes which are too long
ugosantalucia-
I don’t know how others using the other method can avoid having spokes which are too long
By allowing for strain at some other point in the calculation. ERD is, for my money, properly defined as the diameter to the spoke ends at full tension. Where you want the spoke ends to be depends on the nipple geometry, and where they end up depends on the strain, so somewhere along the line you need to account for those things, whether by rule of thumb or rigorous calculation.
gbj_tester
Yeah, it’s just another nail in the coffin for trusting manufacturer supplied erds.
Tbh even when a retailer like SJS gives ‘measured’ erds for rims they sell I haves hard time trusting them as I’ve found a) discrepancies between their measurements and my own and b) discrepancies in their own measurements where they’ve given one number in the item description and another in response to questions about the item!