Currently run tubeless at around 28 rear and 25 front on various tyres between 2.2 and 2.4. New bike (full suss e ) had 2.6 minions on 30mm 29 rims. I’m guessing I should start with pressures a bit lower ? Was thinking about 22 front and 25 back as a starting point ?

Weight…riding style…terrain…we can only guess without knowing these.

Your suggestion seems sensible.

Yeah, I know, bit of a vague question while musing my new purchase 😂

What Al said.

As with any tyres, it’s trial and error with a good repeatable gauge.

My digital Topeak gauge is fine for normal tyres but was next to useless on the fatbike. I picked up a trials bike gauge and have had much better luck finding the sweet spot.

In theory the bigger the tyre, the wider the rim the less air you need to maintain tyre shape and stop rim strikes as that pressure acts over a larger area

Weight…riding style…terrain…we can only guess without knowing these.

I disagree. We know what pressures work for this rider with the smaller tyre because the OP told us. Someone with experience of running both sizes would be able to consider the different pressures they use on the two sizes and give the OP some practical advice.

I run 2.35s and 2.6s (nominal) and probably slightly lower pressures, but @ianc’s suggested differences (3 psi) are about what I end up with. That is with 32mm id rims for the smaller tyres, 36 for the 2.6s.