Are you able to position your front wheel so accurately at the frame centerline that your brake disc is not central in the caliper slot? If the answer is yes, then maybe your rim isn't spoked to the correct offset?
The brake disc is definitely not centered in the caliper slot, but all the evidence points to this rotor. I have another Commando to compare it to which does have its disc centered and the rims are in the same position relative to the forks. As stated
I place rotor on granite flat surface with the rotor side down and used depth gauge on caliper to measure distance from mounting surface to the granite. Also used micrometer to measure thickness of rotor & flange. I did this with 3 different rotors:
| Rotor | Mtg Flange – Rotor outside surface | Rotor thickness | Mtg Flange thickness |
| 1 - | 0.918” | 0.263” | 0.293” |
| 2 - | 0.860” | 0.252” | 0.271” |
| 3 - | 0.870” | 0.248” | 0.266” |
Just sent it to TrueDisk for that.
The essential parameter is rim to hub flange distance. Rim to fork distance is no usable parameter in this context.
This is a moot point for me since my issue is the distance between hub flange to outer rotor surface. I don't think rim position is affecting that and hub spacing is correct.
I humbly disagree. The first step in a clearance assessment is to ensure the front wheel is central to the frame. That's done by sighting the rim and moving the wheel sideways as needed. Provided the offset is correct, this will determine hub position including rotor flange vs. slider. At this stage, you can assess rotor-to-slider clearance and take the appropriate measures.
I am not following your logic. I could mount the front hub with this rotor without the rim or spokes attached and I would still find that the rotor is not central to the caliper slot and its outside surface is in contact with the pad and barely clear of the slider. That is because the rotor mounting flange thickness is too large. To me, how the rim would be positioned relative to the hub when the wheel is spoked is an important but separate issue.
Edit: This is me being dumb - look two posts later!
I assumed they were the fork legs, and the hub is not centred but positioned by the TS spacer and the TS leg, the DS leg floats and is finally positioned by compressing the front forks before the pinch bolt is tightened.
Oops! That makes sense - the measurements are way to wide to be the rim - I should have converted to inches so it would have been clear to me that I was being silly!
Yes if trued correctly, but with the nearly vertical Disc side spokes its hard to get it right. I never bother to get a front rim too right on truing ref the offset and do the final true when its mounted between the fork legs and then get it centred.
I like that idea. When I build them, I get the disk side almost tight enough with a negative offset of about 1/8" and then pull them to spec with the non-disk side. I can't imagine a wheel harder to get right than a Norton front disk!
correct, the grey bars are actually the sliders
So, I'm still being thick, are the measurements to the inside of the sliders or to the center of them or what? I'm asking because I've fought two front ends lately and in both cases was looking for a double-check. Kind of silly since my rider was sitting right there with everything original!
I use wood stickers under the rims, thickness is the offset for the disc side, and wheel is laced with that face down. I find that if I keep checking that the rim is resting on the stickers as I add spokes the final offset when mounted is pretty darn close... it's what works for me anyway
