Bearing Installation on Lefty hubs
HyperLefty (1-2-3) bearing tolerance matching.
The tolerance matching on Lefty hubs of any brand is really complex.
At our factory assembling we manage it using tricky micrometer-tools, but for riders and bike-mechanics it can be a real pain.
All HyperLefty hubs are assembled and very carefully tuned onto an official Cannondale reference-axle.
Anyhow in the fork production you may find slight tolerance variations of the fork axle length, this will result in a looser or tighter bearing preload.
Too loose bearing preload equals play at the rim, too tight will quickly damage the bearing races.
Do not change bearings if not really necessary since that will fully messes up the tolerance matching we made at the factory.
Note also that the factory bearings have a small dot on the seal, that side should be mounted outward.
That because the tolerances involved are super tight, thereafter even inserting the same bearing unit with one face out or the other changes the total assembly significantly.
SS shim
When necessary the 0.1mm shim should be mounted between the smaller bearing and it's internal shoulder, when assembled it adds 0.1mm to the left-to-right hub width.
That's the distance that in conjunction with the fork axle may help to tune the bearing preload.
On our assembly line each HyperLefty get very carefully tuned onto an official Cannondale reference-axle.
Anyhow in the fork production you'll find slight tolerance variations of the fork axle length that will result in a looser or tighter bearing preload.
Too loose bearing preload equals play at the rim, too tight will quickly damage the bearing races.