pic: WCD

[Akash Rastogi]

Originally Posted by compwiztobe

And I'm not sure what, if anything, direct driving the center wheel would have to do with an exact c-c?

He is concerned about losing mobility (chain popping off) when using #25 chain without bearing blocks.

[Aren Siekmeier]

Originally Posted by Akash Rastogi

He is concerned about losing mobility (chain popping off) when using #25 chain without bearing blocks.

I still see no difference between an indirect drive with bearing blocks and an indirect drive without, since maintaining tension on the chain from transmission to first driven wheel is as simple as a slotted transmission noun. That point of failure doesn't depend at all on an ability to move wheels to adjust tension. And beyond that, the system is identical to a direct driven WCD (w/ or w/o blocks). I see bearing blocks and direct drive as two completely independent design decisions, though if there are other details I have overlooked I would be glad to hear them.

[Chris is me]

With a direct drive live axle drivetrain (or any chain drive), you need a method to tension the chain. Since this isn't an indirect drive, moving the gearbox isn't an option. The most efficient way to do it is to move the wheels slightly outward or inward, hence bearing blocks.

[craigboez]

We had an 8WD WCD last season. The siderails were 1" x 2" x .125" rectangular tubing, and we put the bearings right into the siderails, no bearing blocks. They were designed to use exact C-to-C for #25 chain. Our thinking is that if the chain ever stretched to the point of being a problem, we'd replace it with new un-stretched chain. This served us well through two regionals. We never replaced a chain. Looking back, I think I'd have the students replace the chain at the beginning of each regional just to be safe.

See here for CAD:
http://www.chiefdelphi.com/media/papers/2752