I am building a wheel with an Alfine 8 speed hub which has space for a disk brake. I am measuring the dishing by supporting the rim and measuring the distance from the table to the end of the through bolt of the hub, then flipping the wheel over, make the same measurement and then compare. They should be the same so that the hub is in the middle of the rim.
I am now on my third attempt after truing the wheel laterally and vertically I check the dishing and it is leaning towards the right (chain side) by over 1cm, cm not mm. By eyeing the wheel the hub does not look too out of center.
My question: is this method of measuring the dishing suitable for an Alfine hub with disc brake or should I expect some difference between the sides. Basically the difference is too great to be altered by adjusting the spokes.
Thanks for reading.