Silly bearing choice?

At the moment I am rebuilding my Z1000A1, going back to mostly period-correct mods (not that I am a stickler for originality, but I thought it'd be fun). First of course: chassis & braking. Got myself a nice 70s 'Nico Bakker' braced swingarm. Had it powdercoated and thought 'those bearings feel kind scratchy, why not put in new ones'.

Sooo: did a search for INA NKXR25Z combined needle/ball bearings...

Holy cr*p!
Listed as USD 195-and-a-bit

EACH!

These must have been expensive way back then as well, so why use them? That swingarm must have cost a fortune. Which finally leads me to two questions:
1 - Why would they do this? Is this so much superior to regular needle bearings?
2 - Does anybody know a place where I can get these at a sane price?

Jeroen
PS: this is how they look:

ive never seen them before,are they that much better? and will the bike ever be ridden that hard to notice the differance?

Looks like it's supposed to take up end play without causing the friction.

On the stock system (on the 550's anyway) the end play is taken up by optional shims. You get the shims as the end of the swingarm tube wears (because it rubs against the frame bosses). It's a crude system, but works ok if you grease it before assembly. It's a pain to get the shims in there, though, and if you torque the swingarm shaft too much, the swingarm has resistance to it's movement. You have to get it just right to have free movement with no side-to-side end play on the swingarm. I could notice it after the first time I put in the shims, but that's because it was pretty loose before.

Here's the fiche. Notice part labeled "A", and that it is an option.

Your super-costly bearings look like they address the issue by preventing any resistance to movement even when there is no end play, but won't cause the end of the swingarm to wear away. I don't know how the factory addressed this on the bigger bikes.

ive never seen them before,are they that much better?

Well, thats what I am curious about. I've seen other systems, Kruger & Junginger (SP?) use conical bearings like those that most of us fit to the steering head. Combined with their system for exactly adjusting these, that is a pretty nifty solution, because it means no part of the swingarm ever rubs against the frame, and all surface-contacts are through the bearings. And these conical bearings are cheap too. Good engineers these Germans. Nico Bakker was - and still is - a famous frame builder, who has been designing and building one-off frames and frames for production cycles (I believe he designed the frame for the modern Laverda's) for over thirty years. So he must know something. But that price for a single bearing is just silly, so I'm thinking: where's the catch, what makes it worthwhile?

and will the bike ever be ridden that hard to notice the differance?

Probably not...but the idea of a Bakker-swingarm is just really cool for a Dutchman, whereas we still have some unresolved feelings towards the Germans, good engineers or not.

On the stock system (on the 550's anyway) the end play is taken up by optional shims.

On the Z1000 (mine anyway) there was no need for shims: just the end-caps on the swingarm.

Jeroen