Mountain Biking - What's the best tire pressure?

I'm getting a Gary Fisher HOO KOO E KOO with Panaracer DH Pro tires and Maxxis DH Tubes. I'd like to know what tire pressure would be the best for the kind of riding I'm doing. Unmaintained gravel roads, atv trails, mountains, rocks, tundra, mud, soft sand etc. The longest I have done so far is 2 hrs and that will increase by a lot.
I weight 185lbs and 5' 9.5", age 53 and I am not going to do any jumping.

There is no "best" tire pressure. You will have to just play around with it for different type terrains. Some people run 20 psi, some run 60 psi. Find what works for your riding style, your tires, and your terrain.

There is no "best" tire pressure. You will have to just play around with it for different type terrains. Some people run 20 psi, some run 60 psi. Find what works for your riding style, your tires, and your terrain.


LowCel

I understand what you are saying. It's easy when one is running in one kind of terrain, but when I go out I hit every kind in the same day or run. Okay what would be the safest psi to go down to without worry of the tire coming off the rim?
I know that I can bring my Jeep down to 15psi no problem, but lower that that I would need beed lock rims to keep them on.

Different tires, rims, tubes, riders have different minimum amounts they can handle. There really is no answer. You have to keep in mind once you drop the pressure you increase the risk of pinch flats as well, it's not just the tire coming off the rim.

Basicly, you are just going to have to play around with different pressures. For me I would probably run 38 rear, 35 front. That is just my favorite combination for the tires and the trails that I ride. It also helps that I run tubeless so I don't have to worry about pinch flats. Someone else will say run 22 psi, someone else is going to tell you to run 45 - 55 psi. Who's right? Who's wrong?

The main factor is your weight aswell. Since you are riding all differen't types of terrain its harder to get 'one' good tyre pressure.

A lower tyre pressure will provdie more grip, but may slow you down. A higher tyre pressure will make you roll a lot faster but may not grip aswell.

If your not going to be doing any jumping or such then a lower tyre pressure sounds good, but like LowCel said, just experiment. Start running 40PSI, then your next ride run 35PSI, then 30PSI, then 25PSI. Pick the one that feels the best for your set up.

I'll also add to this long post by giving an example of how i've changed my tyre pressure's with different tyres. I had Panaracers Fire XC 2.1" and i needed to run low pressure of 30PSI. I then bought Kenda Nevegals 2.1" and i'm happily running 40PSI with the same traction on corners. There are many variables.

:)

The main factor is your weight aswell. Since you are riding all differen't types of terrain its harder to get 'one' good tyre pressure.

A lower tyre pressure will provdie more grip, but may slow you down. A higher tyre pressure will make you roll a lot faster but may not grip aswell.

If your not going to be doing any jumping or such then a lower tyre pressure sounds good, but like LowCel said, just experiment. Start running 40PSI, then your next ride run 35PSI, then 30PSI, then 25PSI. Pick the one that feels the best for your set up.

I'll also add to this long post by giving an example of how i've changed my tyre pressure's with different tyres. I had Panaracers Fire XC 2.1" and i needed to run low pressure of 30PSI. I then bought Kenda Nevegals 2.1" and i'm happily running 40PSI with the same traction on corners. There are many variables.

:)

As everybody says trial and error. But seeing how low you were with your Panaracer's, and the new tire/tube set-up I'm getting, I'll probably start at 30psi. My main concern is traction especially in corners that are almost all covered in pebbles and small rocks. I've really been nervous, especially on the downhill corners and straights with the same cover.

My very rough, uneducated guess, when it comes to tire pressure....

try ~40psi. give or take some.

I forgot to mention the tire/tube sizes:
Tires Panaracer DH Pro 2.3" wide and the Maxxis DH tubes match and at a 430gr.