JoeyBike

After tires, your riding technique will make a world of difference. Ever see the Paris-Roubaix bike race? It covers well over 100 miles of dirt, gravel and cobbles. Everyone uses road bikes with relatively thin tires. Maybe you can do a web search for their equipment list for starters.

Then, there is technique. On a rough surface, forget spinning. Shift to your largest chain ring - this helps prevent chain slap for starters. Pedal in a high enough gear so that your arse barely touches the saddle due to your legs pushing down on a hard-to-pedal gear. Not too hard or your knees will soon complain. Keep your elbows bent and use them as shock absorbers - that's what downhill off-road racers do, even with full suspension. Stand up on the pedals on really rough stretches but shift to an even harder gear for that. Pedal slowly - like on a stair climbing machine. Let the bike bounce around. Use both elbows and knees as shock absorbers, not your hands and arse.

This technique clinic of mine only scratches the surface. Go to YouTube and search Paris-Roubaix. There are dozens of vids. Watch the riders. Somewhere online there must be more information regarding technique for road bikes on rough surfaces.