They do publish the maximum cold pressure the tire can maintain on the side of the tire. It can very greatly from tire to tire. One tire can be 35lbs, one can be almost 50lbs... Same size and intention. The simple fact there is that if your last tire was a heavier one that liked more pressure, you could blow-out a tire that works properly on lower pressure if it's above it's limit. On the flipside as which was my case, if the tire is setup for higher pressures, you might notice the nice old mid 30's you ran and loved on the old ones feel like mush now which leads to the 'slipping' feeling from having an under-aired tire as well as aggressive tire wear problems.
In a car, I have the perfect solution for any vehicle. It's a chalk test. You find a good flat parking long with at least say 300 yards of strait, flat area. Drive first for about 15 minutes to warm up the tires so they are at operating pressure. Chalk all four tires (pressure needs can be different on each corner depending on the vehicle) with a 6" wide strip all the way across the tread and slightly up the sidewall. Drive slowly (10MPH or less) as perfectly strait as you can for a hundred feet or so. Stop and check the pattern. If it's wearing the chalk off the outside first, it's underinflated, in the middle or not quite to the outside, overinflated. Smooth and even all the way across, perfect. Now wait for them to cool off (next morning) and check you're pressures and you have your cold-pressure settings for those tires and that vehicle.
However, I have no trick for bikes that is so simple. I start a bit low where it's mushy, add a pound or two until it feels solid. Then add 150lbs to the back and repeat it. It's long and annoying but it's the closest thing I can find.
Even these tricks aren't perfect. Humidity, temperature, altitude, etc. all play a factor so... Unless you do them every morning in every spot, they will never be perfect. But still, they are going to be tons better than joe-blow who doesn't even pay attention to his pressures. You'll get even tire wear, more tire life, etc. If you want to go for higher MPG, you can increase pressures a bit, but you lose performance, stopping distance (Safety), and tire wear so the cost is a wash anyhow...
Those are the only 'tricks' I know but they work pretty good. The car one takes all of 15 minutes with a portable electric pump or CO2 Tank (popular with off-roading rigs). Bike one takes an hour or so though but I don't have a faster way to do it. If you don't have a portable tank, you can run them high to get started and slowly remove air to get them perfect or in the case of the bike, run them close to max tire capable pressure and remove a pound at a time until they just start to feel mushy, add a few lbs back. If you don't know how to feel the early signs of the mushy though, don't do that method.
Anyone have a better way? I'm all for finding better solutions.