The bearing spacer discussion

[Sunnyape]

I'll re-hash it.

I think the need for a spacer between the bearings is valid for people using wheels with axles with nuts. The spacer effectively prevents the bearing inner races from being pushed in too far if the skater over-tightens the axle nut. Pushing the races into a permanently offset position will result in premature wear when rolling. For those using flip axles, they're of no real use. There's sufficient clearance in the system that the inner races will never get into that offset position.

I've read some descriptions of spacers being responsible for transferring loads between the inner and outer bearings when cornering, which seems rational, but if you swap your wheel positions from time to time to balance their wear rates, you'll be balancing any differences in bearing wear too. Same happens when cleaning, re-lubricating and re-installing the bearings.

Skate bearings are more than capable of accommodating the side loading we subject them to will no ill affects other than marginally more wear on the sidewalls of the race channels, but probably well within the range of being proportional to the lifespan of the materials they're made from. When bearings wear out from excess side-loading induced wear, then they're probably worn out from normal use anyhow and need to be replaced.

All the other reasons I've read about spacers being able to compensate for bearing alignment, slippage in the hub, axle flex etc. all seem a little too fanciful for my liking. Even if they did perform all those duties, it's not as if you'll achieve some measurable increase in the lifespan of the bearing, the hub or the axle anyhow, because all the other normal usage and wear factors will prevail.

Then, when you factor in the variations of the spacing between the bearings due to manufacturing differences in the wheels themselves (refer to the wheel cross section pictures in the 5th page of the Show Us Your Wicked Lips thread), the idea of there being a single spacer that does its magic on all wheels gets every harder to imagine.