i just recieved the sizer rings that are to up-size the Profile bearing to fit the 42mm KH bearing holders but i dont need them.the Profile size is big enough and the holders have enough tolerance to work great without them.
you will need the bearing sizers if you use 40mm bearings on a profile hub with the Production KH frame but you wont need them if you use the bigger Profile size.
It’s a better fit for me with them. It’s close but the bearing holder surface doesn’t make contact throughout the entire circumference of the 1-5/8 bearing, at least on my frame.
Install the bearing by itself, without the axle and see if it touches at the outer edges, near the cap screws.
i checked that out before commiting to the build up but it is very close,esspecialy when tightened down.call it a class B fit.
its close enough that im not going to take off my cranks to install them but in a couple of months when i strip it down for cleaning,i’ll use them.i could install them instantly by slitting them but that would be a shame.i’ll just wait.