Front wheel not central?

My new outboard disc hub wasn't sitting central in my forks, it was about 9mm off. I don't have a photo because I was too annoyed to take one.

I couldn't work out why this might be, and a bit of googling only led me to one theory that I had a bent fork link. I can't possibly imagine a scenario where a fork link might get bent. If your fork link was exposed, in situ, to enough force to bend it then other things would bend or break first, surely?

With this in mind I dismantled it again and found the culprit. In the photo below you can see uneven wear on the face around the edge of the bush. The face has worn to the rear of the link (the top in this photo), but not at the front. This causes the link to sit at an angle when fitted to the forks.

The fix is simple. I filed the rest of the face in line with the wear so that the face was perpendicular to the bush/bolt that holds it in place. Then to compensate for the loss of width I doubled-up with another cup on this side, as not very clearly shown in this photo. You could also use a large penny washer under the cup.

While I'm on the topic of fitting the front hub, an important part of fitting your front hub assembly is using the right axle washers. They ensure that the hub sits exactly where its supposed to be but are more importantly a critical safety feature which will hold your wheel in place even if your main nut becomes a bit loose.

It's all back together now, and I'm pleased to say it sits perfectly in the middle!