Shimano SORA FC-R3000 Dealer's Manual page 18

MAINTENANCE
Replacing chainrings
FC-R3030 / FC-R2030 / FC-R2030-CG
1
(C)
2
With the marked side of the largest
(A)
chainring facing outward, set the largest
chainring so that the chain drop
prevention pin is positioned under the
crank arm.
(B)
Set the middle chainring and the
smallest chainring so that the marked
sides face inward and the alignment tab
on each chainring is positioned under
the crank arm.
(A)
(B)
18
(A)
Mark
(B)
Crank arm
(C)
Chain drop prevention pin
(A)
Crank arm
(B)
Alignment tab
Smallest chainring
Tightening torque
16 - 17 N·m
Largest chainring/Middle chainring
Tightening torque
12 - 14 N·m