I personally replaced the eThirteen chainring on my Rise with Shimano Spider w/ 34T for Shimano 12-speed chain (
SM-CRE80-12-B ) but it looks like the smallest chainring Shimano sells is a 34T (while the rise comes with 32T).
FSA also sells a spider for the EP8 with a 53mm chainline (
W0154 - 380-0455000050 ) and it can be coupled with the
RaceFace 32T Chainring for Shimano 12 speed (
1x Chainring 104 BCD - SHI 12) if one wants to keep the chainring at 32T. Even though the Shimano spider is meant for a 104 BCD chainring, it's meant to be used with a Shimano chainring due to the profile of the the arms. If you were to use a RaceFace 32T Chainring (which is also 104 BCD) on a Shimano spider, you'll have a GAP and it won't look seamless (aesthetically) due to the inner tabs being a different profile than what's on the Shimano spiders. The FSA spider is more seamless looking when coupled with an aftermarket 104bcd chainring.
People already reported shearing their eThirteen direct mount chainrings in this forum (and it's a pain in the ass to remove the chain mount lock ring afterwards, one even had to get the motor replaced).
This means that you won't be able to use the eThirteen chain guide. If you want to run one, here's a pic of
FUNN Chain guide for the Steps Motor on my bike (coupled with the Shimano Spider) - Rise H30.
OneUp also sells a Chain Guide for the EP8 motor as well.
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