Administrators: If this topic has been covered elsewhere then by all means please accept my apologies and deal with it as best you see fit.

I recently did some distance on what I would call fair to reasonable dirt road.
The vibration/noise/harshness was something horrendous.
I'm hoping it can be alleviated (in whole preferably, 'though that might be expecting too much) when I eventually come to change tyres, which are currently the 235/55 R17 Dunlops.
The placarded pressure is 44psi (front). Next time I go off bitumen on a similar road surface I'll be dropping the pressures, but one wonders how far can that go?
Any comments please?

Secondly: while I'm quite happy with the road noise on bitumen surfaces, there's a lot of "bump-thump" reaction when passing over manhole covers, train line crossings, etc. Again this would be reduced a little by lowering pressures but I don't want to ruin the tyre life by wearing out the outer edges prematurely.

Maybe the 44psi recommended is too high? What do you folk out there use - what experience have you had over a longer mileage than I've done (17,000km only, so far...)

Any tyres out there which are significantly smoother and quieter (particularly off-bitumen)?

Thanks ...