Bearings vs Bearing Blocks

[Monochron]

Originally Posted by DampRobot

Solution 1: exact center to center design
.
Disadvantages: very tight tolerances. You need to get bearing holes to withing -.002/+.000 IIRC (it's been a while) to get a good fit, and center to center distances probably need to be +/- .005 for belt and +/- .01 for 25 chain. (It's been a while, and I'm mostly pulling these numbers out of my behind, but these should give you an idea of the tolerances required.) If you get it wrong, you have to remake everything. Generally harder to assemble and to maintain if it breaks. It often requires a heavier drivetrain, as you must use .125" tubing to properly support the bearings instead of much lighter .0625" tubing. Getting an efficient system is pretty hit and miss.

Maybe you could shine a little light on how center to center behaves with a chain that stretches over time. For instance, we have attempted center to center with success in the past, but we have no where near the tolerances the list as "needed". Would better tolerances cause less stretch in the chain? Basically, I'm still skeptical that you can run chain without ever planning to tension it. I have heard of it being done, I'm just not sure how.