msl109

Amen.

msl109

Question - at first I thought double square was a brand... , realize now it's a type - any recommendations for a brand or where to get them reasonably? Also came across DT "Squorx" - are these the same but with a Torx head? Thanks again.

oberwl

I almost never use the manufactures data. Only a very few that are accurate to what I measure. e.g Velocity seems to be spot on. Any how here's the process I use if it helps with getting the measurement correct. Probably everyone else on here also does this, but just assumed you're doing things also correct . I wont' assume that.
With spanners measure Duh Overlocknut. Then Flange diameter hole to hole. Then take a cone wrench and rest it flat against the locknut, and measure from flange to the cone wrench. Take Half Overlocknut minus this measurement for each side of hub, flange to center of hub.
Measure 2 spoke from threads to 250mm length and cut, then glue nipples on till they are just flush with spoke. Put the 2 spokes through the rim and measure the distance between the ends of spokes. Example I measure starting from the 100mm mark with a spoke ruler. So lets say it's from 100 -144. So my ERD is 544; 250mm X 2 + 44mm. Now put all this in a reputable spoke calculator like wheelpro or bikeschoo.com and you should have your length.

msl109

I did all of that but devised something else to measure the ERD (a derailleur cable pulled taut across the diameter and some other voodoo I can't even remember, but I came within 2 mm (603) of what others have posted here). By flush with spoke, you mean with the top of the spoke just at the bottom of the nipple slot? And the reason I didn't use your approach to measuring ERD, which I'd seen variations of: how do you know the spokes are straight when you measure the distance between them? I'd think you'd need to be sure they're square in the hole, pulled taut, and need a third hand to do so, no? A Vise Grip securing the spoke where the nipple meets the hub side of the rim eyelet, maybe?

oberwl

When I cut the spokes I make sure they are straight. I usually use some new spokes, then keep them in a safe place where they won't get bent. When I put the spokes through the holes I pull on the left with the ruler in one hand and the right in the other hand then read the gap length. In this manner the nipples are taken into account.

Going by your method, how do you determine where the nipples will seat themselves. I've built a lot of wheels and this method has not yet failed me. BTW, it's the method taught at United Bicycle Institutes school, and my guess also by Barnett in Colorado. It's pretty much the De Facto standard bar using Wheelsmith's spoke stick tool.

DannoXYZ 

Have you measured an actual spoke that was delivered?

sweeks

Here's one way to do it: Measuring Effective Rim Diameter | Park Tool
Steve

msl109

Good to know - I'll try it that way. But when I asked how you knew the spokes were straight, I didn't mean whether they were bent; I meant exactly perpendicular to the rim bed when they are only being held in place by hand.(?)

As to your other question, I honestly don't recall how I measured where the nipples seated. I believe I seated the spokes and scratched with a blade the exact place on the nipple where it entered the rim at the inner rim circumference, then measured the distance (thickness) between inner and outer eyelet. I knew my margin of error was within a mm or two. It's one of those had to be there things and I'm not sure I'm even recalling what I did accurately. But of course 2mm margin of error can mean 4mm overall, so I erred on the side of having a thread or two exposed when the wheels were built. Given that I have three wheelsets to build, the Wheelsmith tool sounds like a good investment.

Soil_Sampler

There is more than one way...

https://www.bikeforums.net/10101859-post18.html

sweeks

There's *always* more than one way!
I think the "direct" method is easier for bare rims, but that's a neat way to measure ERD on a built-up wheel.
You could also measure the circumference, calculate the diameter the "traditional"* way, then subtract the rim depth twice.
That's three right there!

* D=C/2Pi
Steve

EDIT: *FOUR* including those cool "rim rods" you linked to.

Soil_Sampler

2 spokes
2 nipples
Loctite