Herzlos

So I've purchased a new set of wheels that I absolutely don't need because they were 75% off and 400g lighter than my existing set. The justification is that I've got a spare set of tires and cassette just sitting there and this will prevent them being wasted.

I have the following:
11-34T & 11-36T cassettes
Deore and 105 Discs
Giant CrossCut 700x38c and WTB Riddler 700x44c.
Vel 23 wheels (lighter set). Max pressure 50psi
Giant PX-2 wheels (heavier set). Max pressure 75psi

The Deore discs need to go on the Giant wheels (6-bolt) and the 105's on the VEL (centrelock).

Everything is tubeless. The roads here are terrible so closer to gravel than tarmac in a lot of places.

My initial plan was to put the 11-34T and the 700x38c tyres on the VEL wheels for a 'fast' configuration, and the Giant for off-road. I'd have been running the tires at nearer 75psi, since I weight ~95kg (200lbs), but I'd need to run them at the max 50psi.
The other option is to put the 11-36T and the 700x44c tyres on the VEL for an offroad/climbing configuration, and the Giant for on-road, where I'd be running at 50psi anyway.

What do you think would make more sense? Am I better trying to run the 38's at 50psi and go for the fast set? Or am I too heavy?

shelbyfv

I've made some assumptions but the SILCA calc seems to think you'll be ok at 50psi. Check it out.

tFUnK

When I upgraded from my stock wheels to a set of carbons, I contemplated the same question: does the lighter or heavier wheelset do road vs. gravel duty? On a whim I threw on some 33mm slicks with TPU tubes in case I change my mind later (so I don't have to deal with sealant).

In practice however I never want to ride the heavier set of wheels so I'll just swap tires if I want to do a gravel-heavy ride (or not - as the 33mm slicks have performed beyond my expectations on hard-pack trails).

So having said that I would recommend you setting up the nicer wheels with the configuration (fast or slow) that you are likely to ride the most frequently.

Surprised that the wheels have such a low psi limit but 50psi on 38mm tires should be fine for your size (I'm similar mass and routinely run 45-55psi on 38mm (true width) tubeless tires).

Herzlos

I was surprised by the limit too, especially since the pressure must depend on the size to an extent - more square inches at the same pressure means more force - but I guess the rim contact area is largely the same in any case.


@shelbyfv that's a great link. I'd tried a few calculators before and was given much higher figures.
I think I'll give the fast option a go first, since it looks like 50psi will be fine. That's especially convenient because it means the slow wheels are already set up.

It's probably also the set I'd use most, reserving the wider ones for really rough stuff, or no doubt just never actually use it like @tFUnK found. I'm not sure how drastic a change it'll be as both are alu, one set being about 2.2kgs and the other about 1.8kg.