Rival long cage might be clutched. this on is:
https://www.bikester.co.uk/sram-riva...er-662643.html

Regarding tyres, I run the 650b with 50-584 and pressure is 30psi front 35psi rear. the 700c are fitted with 33-622 and I run 65psi front and 70psi rear

you can also look at that: https://axs.sram.com/guides/tire/pressure