Tire pressure advice for 20" rims

[Baron Blubba]

Here's a set up that isn't accounted for on any tire pressure calculator I've found.

20" disc brake wheels with 23mm inner rim width.
20" Maxxis Torch tires, 20 x 2.2"
Tubed, using Tubolito TPU tubes.
I believe Maxxis recommends 35 - 110 psi for these.

I am 140 lbs, going for a big ol' gravel ride tomorrow. 35 will yield a pretty rough ride, I'm thinking of going down to something like 25-30 psi. Any reason not to? Would the TPU tubes create a reason not to?

For reference, I'll run my 700x40 Schwalbe G-One RS tires on Enve G23 (23irw) wheels at 30ish psi when doing gravel-centric rides on my Mog.

Would love to hear everyone's thoughts.

(PS: These Black Snow wheels feel really nice, but man I wish they were tubeless.)

[prototoast]

The air volume of a 20x2.2" tire is approximately the volume of a 700x45 tire, so pressurize accordingly. If you're running a 700x40 tire at 30 psi, you'd want a to run your 20x2.2" tire at around 25 psi to get a similar feel.

[Baron Blubba]

Originally Posted by prototoast

The air volume of a 20x2.2" tire is approximately the volume of a 700x45 tire, so pressurize accordingly. If you're running a 700x40 tire at 30 psi, you'd want a to run your 20x2.2" tire at around 25 psi to get a similar feel.

Thanks. Thing is, the Mog is tubeless, the minivelo is tubed.

[NHAero]

Mike, what do BMX riders set pressure at?

Is there a reason that a 20” tire of a given cross section would require a significantly different pressure than a 26” tire? I run my 26x2.2 tubed Conti Race Sport Speed Kings at 30 psi or less for mixed riding that includes mild single track and I wouldn’t hesitate to drop that a bit more. These are on older American Classic rims, so not modern wider inner dimension.

[prototoast]

Originally Posted by Baron Blubba

Thanks. Thing is, the Mog is tubeless, the minivelo is tubed.

Don't worry about it. It's really hard to pinch flat a tire that big unless you're doing MTB stuff.

[Baron Blubba]

Great advance Marc and Dan, thank you very much. Going to try this at 25-30ish psi tomorrow.

[Davist]

Originally Posted by NHAero

Mike, what do BMX riders set pressure at?

Is there a reason that a 20” tire of a given cross section would require a significantly different pressure than a 26” tire? I run my 26x2.2 tubed Conti Race Sport Speed Kings at 30 psi or less for mixed riding that includes mild single track and I wouldn’t hesitate to drop that a bit more. These are on older American Classic rims, so not modern wider inner dimension.

for both racing and freestyle bmx they run pretty high pressure to prevent flats I guess. I'm way out of date but still see "high pressure" rated tires for bmx. I ran as much as the compressor would give me (so close to 80psi plus) 20 x 1.95