Depends what kind of offroad. I found the Bilsteins too stiff for rough roads, with the car bouncing around as speed increases. For slow offroad they're OK. But you're better off allround with a set of standard dampers, even new those are cheap.
Thanks for the tips I bought them(Billsteins) for $13 each at the junkyard when I was looking for sunroof parts for the p38.
I also have a 1" lift plate from Utah Rovers. II am putting it all on Wed. I will probably try 18-20lbs next time
Last time I did not air down because my tires were old and I noticed cracks, should be ready to roll now.
My 99 has BFG K02 tires on 16 inch wheels. I have done some pretty serious off roading with tires at 20psi. I don't think I would go lower. I had a Disco 1 with Bilstein shocks and I liked then for on-pavement driving. I don't know if they make single acting shocks anymore, the ones that only restrict downward bounce, but the Bilsteins are double acting so you get much better control. I think they would be fine off road.
Agree 10psi is low, with risk of pulling a tyre off the rim or dirt getting in at the edges and causing (slow) leaks. 20psi should be fine.
I know the Bilsteins get good reviews on older Land Rovers etc, but I find they just don't work well with the airbags on the p38. On a previous P38 I replaced the recent Bilsteins from the PO with old original dampers I had on the shelf and the ride improved noticeably on anything but the smoothest roads. But as said, for low speed offroading it wont make a difference.
my two bobs worth - anything that stiffens up the suspension will degrade off road performance. The whole idea of the original range rover suspension was to get lots of articulation and make it easy to keep four wheels on the ground. With respect to tyre pressure, the classic handbook used to recommend 15/20 psi for sand etc. but that is not in the P38 handbook. Regardless I use it as a guide and default to 15 all round. If you go much under 15 it is easy to roll a tyre off a rim. I know a chap who did that in a creek and wrote off a $70k Landcruiser - killed the computer.
I put the billsteins on with my coils. It seems less roll when turning than the terrafirmas. The terras were easier ro compress by a little.. I am thinking 1 in lift plate still next week. Thanks for the tips