Tire pressure recommendation question

[doomridesout]

I'm soon to order some Light-bicycle rims, and I'm wondering about their tire pressure recommendation. These rims (https://www.lightbicycle.com/XC-650B-mountain-bike-hookless-27mm-wide-cross-country-rim-tubeless-compatible.html) specify a maximum pressure of 40 psi, but list a tire size of 1.9-2.3 as recommended size. If I was to run a 650bx38 tire on this, could I safely exceed 40 psi? Not by much, but I might run up to 60. I know various pressure charts from DT Swiss and Enve state higher pressure is OK when the tire volume is less. Thoughts? I'll be running tubeless.

[martl]

My rule with tire pressure is: stick to the recommendations on the tire (those tire engineers actually had a reason they wrote these on).
If the rim specs are below that, go with a different rim. A rim with a max rating of 40PSi/2,75 bar sounds to me like designed for weight weenies building wall hangers, tbh.

[Tony T]

Is there a reason you need the lightest possible rim for a 650?

[yinzerniner]

My rule with tire pressure is: stick to the recommendations on the tire (those tire engineers actually had a reason they wrote these on).
If the rim specs are below that, go with a different rim. A rim with a max rating of 40PSi/2,75 bar sounds to me like designed for weight weenies building wall hangers, tbh.

This is that's the pressure for a 1.9-2.3" tire, which is the recommended combination. Many manufacturers do this, but also add specs as to the different recommended pressures based off of smaller and larger tires.

See the page on this enve rim sheet on how tire size effects the max pressure:
http://www.starbike.com/manuals/enve-wheel-manual-en.pdf

Basically, 5-7 psi up and down for every 1/4" of tire size. Given that, your max recommended pressure is anywhere between ~50-63 psi with 38s.

And 40 psi on a larger than 2" MTB tire seems super high, and even anything more than 50 psi on a 38 tubeless is very high as well.

[benb]

At around 170 I run/have run 35psi front/45-50psi rear for 700x38. I'm in the 25f/30r range on 26x2.3" or so on my MTB.

So no way I'd be OK running a rim that said 40 max on a 650x38.

No way I'd be touching those for that kind of use. A 650x38 I would definitely be wanting to take offroad. I'd absolutely be overbuilding so I could take the bike where I wanted without worrying about it. Brass nipples for bad weather durability, plenty of rim strength + plenty of spokes + well sealed hubs.