Mount Dual Piston Caliper Behind Fork

mrtwowheel said:

My same discovery, and that was the answer to my puzzle. Thanks Skull.

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I'm not so sure about that........it was an observation.

Swapping the forks, (especially the axle as well), from side to side creates a problem of 3mm, and as your observations show the rotor and caliper don't match up.........looking at my 74 front wheel it has a 2mm at least gap between the fork and the hub spacer. This is on the left side and the axle head itself takes up the gap between the fork and hub.

Because the speedo drive side is narrower than the right side of the hub, (distance between the outside of the spacers and the rotor face on the hub as per earlier pics), swapping the forks from side to side without swapping the spacers, (speedo drive), as well it seems to affect the position of the rotor,caliper, fork placement.

Doing this in my head and here are the other pics i have to justify my thoughts.

Shows how i set up the measurements........the hub is reversed left is on the right and vise versa.......


Next 4 show a 3mm difference from outside of the spacer to the hub Flanges........adjusted the camera position as to show a straight on shot



Measuring from the Hub rotor face to hub Flanges


This shows the rotor face is square to the flanges

Observation

The measurement from the outside of the spacers to the flange has a difference of 3mm from side to side
The measurement from the rotor face to flange is the same for both sides....
The measurement from the rotor face to the outside of the spacers has a difference of 3mm from side to side

Conclusion.......on a factory front spoke hub
There should be a 3mm gap between the hub and the forks on the speedo drive side so the fork and fork caliper is positioned properly on the rotor. The 3mm gap should be taken up with the shoulder of the axle protruding through the fork against the hub.

Swapping the forks and axle from side to side and leaving the speedo drive on the left, there has to be a spacer of 3mm between the fork and speedo drive spacer for the rotor to line up with the caliper..........if that is done the right side caliper and rotor should line up properly.

Very nice post there Skull. Thank you very much for the time that you spent on that.

Scott

Maybe machining off 3 mm from the RH side spacer would make it easier to install the wheel after the new spacer is added? And maybe somehow attaching the new 3 mm spacer to the Speedo drive?

arcticXS said:

Maybe machining off 3 mm from the RH side spacer would make it easier to install the wheel after the new spacer is added? And maybe somehow attaching the new 3 mm spacer to the Speedo drive?

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Yeah, that's what I see now. 2-3mm from the spacer and maybe a couple of small counter sunk screws to hold the new bushing to the fork or speedometer drive. But then my spacer seems to be just right with no changes.

Scott