On 2/13/2018 11:37 AM, Emanuel Berg wrote:
AMuzi wrote:

Which is superior and good engineering for
that overly torqued inner ring hardware.

What is the superior way to keep the chain
straight on tandem bikes?

I once saw a small chainwheel, slightly bigger
than an RD pulley wheel, in a vertical track,
so it could be adjusted up/down to interfere
with the chain.

This made sense to me, maybe because
I understood it, but I have since then seen
modern tandems and they don't have it.

Low-end tandems still use this.
http://www.ritzcarlton.com/en/hotels/japan/kyoto/area-activities/activities/guest-activities/kyoto-tandem-bike-ride