12.2 will really be ok. Spacers do not need to be a snug fit whatsoever.
Also if the spacer is going to be under compression when installed it matters eeeeeven less since it won’t be moving anyways.
As long as the two ends are square, you’re good 
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as long as the misalignment lets it rub on something yeah, just a lil bit off not bad.
I would rather have out by .2 and be metal vs 3d printed and perfect size … I’m also pretty sure some of the cheap ass 8mm ones I’ve been using for years are out more than that 
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Can someone remind what dimensions we need for mbs Rockstar rims?
Someone mentioned 22.2mm in length works do you guys confirm?
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If that’s a trampa, then you know where to go. There’s no run around unless you’re willing to buy large spacers and cut them small.
Yes the inter bearing space is 22.2mm, thats what these are
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I can’t add anything to my cart 
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I just checked and it all seems to be working for me!?
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Length is the most important thing with spacers. ID or OD matter only so much as that they allow the fastener/shaft to clear, and that the end faces are flat and mate with the internal (ID) bearing race. The entire point of the bushing is to ensure that clamping forces (nut and the hanger axle) don’t cause excessive side-loading on the bearings, which will destroy them an order of magnitude faster.
The lack of spacers, shit shields, and our dumbasses as kid flushing out the bearing lube/grease with WD-40, is why we had to constantly replace bearings as kids, the latter being the worst culprit, but the former, a close runner up.
You definitely do not want the ID of the bushing, to be the same diameter as the ID of the bearing however. You want it slightly larger. This is for clearance for the shaft, if it’s the same diam it may rub on the axle shaft and while it’ll be softer material and wear down at a much higher rate than the bearing race, it’ll build up heat, and swarf material (aluminum) that has no where to easily go. If you have more clearance than the ID, whatever minimal material may end up in contact and wearing against the shaft will wear away and at a minimum the swarf can build up around the rest of the ID of the spacer.
In a perfect world of course you’d have your bushing perfectly centered and recessed entirely from the bearing inner race ID face, however this is difficult to do. Either way, it’s lateral force that’s the big concern with radial bearings, which are not designed for heavy or continual side loading.
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