Originally Posted by
cqlink
I think I'm getting there. I'm posting a pic of my hub and Edd's calculations. Problem I'm having is it appears to me the distance from the center of the hub to the flange is the same on both sides. I've looked at all the sites with dimensions for Campy high Flange hubs but they don't match what I'm seeing on my calipers. I'm reading a diameter of just under 65mm. The chart attached below states 67mm. The (W) or center to flange based on my measurement is 27mm(left or WL) and 26mm (right or WL). Actually, the center to both sides appears the same to me.
The hub noted on the chart was as close as I could find to my hub (Campy Record).
I plan to use a 3X patterns as the front wheel is 3X.
I don't want to spend $50 on spoke I can't use. Can anyone steer me from here to find the right spoke length?
Thanks!
Accurate flange diameter and ERD measurements are much more important than the center-to-flange. But best get them all right, of course.
Flange diameter needs to be measured hole center to hole center. You're probably measuring the smallest diameter of the hole circle.
I physically measured one I have here and I get 67mm, with 2.3mm hole diameter.
You're definitely measuring center to flange wrong though. It's not the center of the hub shell that matters, it's the center of the axle. Since that's hidden inside the shell, you need to calculate it. Measure from the outside of the lock nuts to the flange, then subtract those numbers from half the total overlocknut.
On my hub I measure total OLN: 121.5mm
Right locknut to flange center: 37.5mm
Left locknut to flange center: 28.5mm
That gives me
Right center to flange: 23.25mm
Left center to flange: 32.25mm
To be honest, center to flange doesn't require that level of precision, within a mm or so is fine. So that's as spot on as needs be to your chart's C-F numbers. You can trust their hub measurements. Hopefully you can trust their ERD too.
(Not that this will have a huge effect on the calculation either, but I'm not sure why they're saying the CR-18 has a 1mm OSB. The holes are slightly offset from center, but symmetrically left to right. So if they want to factor that it, they should call it a ±1mm, which is effectively the same as zero.
And in case you're wondering why my hub has a 121.5mm OLN, it was probably set up for a 6s ultra freewheel, which would be about 2mm wider than a 5s.)