This answer is for the UPPAbaby Ridge (original), though one maker didn't say which version. Not sure which Ridge you have?
Key specs
Adapter
about $39.99
Weight with carrier
39.1 lb
Stroller folded
18.5 x 26 x 36.5 in (L x W x H)
Good to know before you click it on
Ridge seat and canopy can stay on when attaching a car seat or Bassinet with these adapters.
Do not jog with an infant car seat attached to the Ridge.
About this pair
The UPPAbaby Mesa (original) goes on the UPPAbaby Ridge (original) with the UPPAbaby Ridge adapter for Mesa and Aria (model 0901-RMA-WW), about $39.99. With the carrier on, you are pushing about 39.1 lb (29.2 lb stroller, 9.9 lb carrier).
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23 other infant seats fit the UPPAbaby Ridge (original).
Summary from the makers' published data.
How to set up the UPPAbaby Mesa (original) on the UPPAbaby Ridge (original)
What you need
The UPPAbaby Ridge (original)
The UPPAbaby Mesa (original) carrier
The UPPAbaby Ridge adapter for Mesa and Aria (model 0901-RMA-WW)
The adapter maker shows the fitting steps in pictures; see the manuals below.
Before every walk
Check that the carrier is locked on both sides the way your manual describes. How we check our answers
Last check: give the carrier handle a gentle tug. A seat that is fully latched does not lift off.