I'd second those saying to try a few different pressures yourself and see what the difference feels like.

Normally I'm a "don't care too much about the pressure, pinch and make sure it's not flat" guy, but my last trip, I found when loaded down the tires had to stay near the max or it was like dragging a boat anchor. Wasn't an issue unloaded, but max pressure on the tires were 80, when it dropped into the 65-70 range it was a very noticeable issue.

I contacted Schwalbe with the same question, and they replied to max out the pressure. They did not explain why, but they make the tires

That's a bit odd considering https://www.schwalbetires.com/tech_i...ation_pressure gives some generic guidelines & notes the pressure range stamped on tires. Perhaps Schwalbe avoids individual recommendations for legal reasons. For my 135 lb weight & 50mm tires the chart says to use ~40 psi, a bit lower than I would have guessed.

I've been drinking the Berto/Heine "15% drop" Kool-Aid for 7 or 8 years now, and it hasn't steered me wrong yet. I'm far more comfortable than I was when I maxed out the tire pressure, haven't had any pinch flats, and it doesn't seem to have slowed me down any.

But, I think Jobst Brandt had a legitimate objection to the low front tire pressures these calculations give if your bike has a lot of weight in the rear (40/60 or 35/65 weight distribution) on level ground -- if you're touring on steep hills and need to brake hard on a downhill, nearly all of your weight will transfer to the front wheel, and it needs to be suitably inflated to avoid bottoming out at that critical moment.

So, I use a 45/55 weight distribution for every bike in my stable, whether that's "correct" or not. And then I take whatever the calculator gives me and round up to the next 5 lbs for ease in reading my pump, and to give a little safety margin.

Thus, for the example in the OP, with a 231 lb total weight and a 45/55 weight distribution on 37mm tires (these Schwalbes are marked 37-622), the calculator tells me to put 46 psi in the front tire and 56 psi in the rear. Round those up to 50 and 60, and you'll have something that's a hell of a lot more comfortable than 80 psi, but still very resistant to pinch flats.

I noticed that the original link stopped working a while back, too. I think Jan perceived too many people taking exact numbers as gospel (even though most of the original articles encouraged experimentation) and wants to make experimentation more of a focus. I believe that's why he hasn't bothered to create a 42mm line on the chart, even though a bunch of people have asked for one.

For what it's worth, the original article is still on their site (for now), they just moved it around: https://www.compasscycle.com/wp-cont...BQTireDrop.pdf

so Azza me lad, pipe up and tell us what you tried and what you thought?

60-75 front, 70-85 rear depending on conditions. Start with 65/75