Only use the suggested psi numbers as a general guideline. “Proper tire pressure” depends on several variables, all of which can change the answer by a lot:
Tire width (air volume)
Type of riding (Freestyle? Trials?)
Your style of riding (hard or soft landings?)
Riding surface (flat ground or sharp rocks?)
I grew up riding unicycles with 1.75" tires, in gyms and out on paved ground. 60psi was what Schwinn recommended, and we often went much higher. Lower indoors, to keep your unicycle from spinning uncontrollably. Higher outdoors to keep friction down for easy turns and less tire wear.
But perhaps the common denominator of tire pressure is how much do you need to keep your rim off the ground? That is your base amount. There is no fixed number, because it’s affected by all of the factors listed above. From there, you can add pressure for more bounce or a “stronger” tire (won’t fold over).
Trials often requires compromises. You may be jumping onto small objects that can deform your tire down to the rim. But if you add too much pressure, you won’t have the traction you need for most of the time. So you have to be careful as well.
For specialized situations, you can go lower. For example, in one of the best examples of low-pressure I’ve ever seen, Chris Reeder won himself a case of beer from Bruce Bundy by riding (not hopping) across a sandy volleyball court at De la Veaga Park in Santa Cruz. He kept letting more and more pressure out of his fat MUni tire to be able to stay on top of the sand. At his final pressure, he was almost completely unable to ride on the pavement along the edge of the sand because his tire looked almost totally flat. But it worked in the sand…
Lower pressure cushions and gives you some spring when hopping. High pressure is like jumping on a brick. Things don’t bounce real well.
Low pressure should not be so low that you bottom out on the rim when hopping. You don’t want to be hitting on the rim when you land. So far as psi, you have to figure out what works for you.
Low pressure also lets the tire “fold” over if you land on it crooked. High pressure is fine for real smooth surfaces so long as you keep the wheel on the ground. When you jump/hop, things are a lot more comfortable if you let some air out.
I’ve paid pretty close attention to the question of tire pressure over the last few months–including measuring said pressure with a calibrated gauge–and for Muni riding, I’ve discovered this much.
IME, the only advantage to having a low tire pressure is found on truly grim rolling over super steep, rocky runs. But if the pressure is too low you’ll “rim out” and get pinch flats and a lot of tire fold over, as well as getting bucked off because the low presure produces a very bouncy tire. Oddly, a slightly higher pressure allows for even higher hopping once you get used to hopping with a quick snapping movement. A higher pressure also makes for easier traction on slanted surfaces. With a mushy tire you get side to side movement making still stands between hops quite hard. Just yeserday I was practicing hopping on some domed rocks and couldn’t keep the gap going till I increased the tire pressure. The difference was really dramatic. The mushy low pressure tire was squirely on the rocks, whereas the higher pressure tire bit like a bear. A mushy tire is also a lot harder to steer.
I weigh 210 lbs and like to run a 24 X 3 Durro or Gaz at about 26 psi. I have noticed that when I was just starting the lower pressure was actually better, but as my skillset has slowly improved I’ve found the higher presure means higher performance.
I weigh 160 lbs. and ride about 25 psi in my 2.5" wide Luna… I bottom out occasionally, but only when hitting a narrow landing (2" or less) on a 90 degree angle. You need to experiment and find what you like best. For technical gaps like that, you want your pressure low enough that you won’t bounce off, and high enough that you won’t smack your rim too hard.
You’ll find a pressure eventually that lets you compress and get a good spring, minimal tire foldover, and not bottom out on small landings.
How much do you weigh? What tire/rim are you using?
ME?? 115 on my best days( meanying thats the highest iv been so far) I am riding on a K RAD 2.125 with what ever rim comes on the torker DX. I am starting to get into Street/ Trials. HOPE THAT HELPS YOU HELP ME.
Also what do you all consider low and high. so that i have an idea what you mean by when i ride at a higher psi.
For trials, I consider above 30 psi on the high side, and below 20 on the low… but, like John said, appropriate tire pressure is dependent on rider weight, tire width, rim width, style of riding, and terrain.
Finding what pressure YOU want is simply trial and error.