Here at our battlefield we use banksand...it is red topsoil with sand in it... also a mix of clay and red dirt...
It packs nice (kinda like a hard surface) but still has a nice loose top for allowing the tracks to slip/slide so you can turn.
We run HL, WSN, MATO, TAMIYA all brands of tanks out here... and tanks have metal or plastic stock tracks... all run well...
We don't really have any pebbles in the dirt... very clean soil... looks great when the dirt/sand mix is falling off the tracks or falling out from between the track links!
"ARE YOU COMING IN SEPTEMBER TO the TEXAS ARMOR BATTLE WEEKEND?"
http://www.rcuniverse.com/forum/m_8856450/tm.htm
-CHEERS!
TOMAS
TX ARMOR