The tire pressure that I've been running is ~42lbs. on grass, dirt, sand & short asphalt sections. Sometimes it feels like it's bottoming out on roots etc. if I stay in the saddle. Another thing is that when I'm cornering relatively fast it feels as though the rear tire steps out then snaps back. I haven't flatted, rolled the tire (clinchers) or lost control. Is this normal or is the pressure still a bit low? Thanks in advance for any responses.