Warg-Riders

The Orcs who eventually became Warg-riders were smaller and lighter than others of their kind, and could evidently bear to suffer daylight more than ordinary Orcs. Many carried horrific scarring and other injuries, including missing hands, caused by not giving their ferocious and carnivorous allies enough respect. They managed to ride the Wargs by means of a crude saddle made of hide that was strapped around the beast and sat just behind its hump.

Tactics
The preferred method of attack was to let the Warg do all the initial work, and if there was any dispatching to be done, they would dismount, if it was safe to do so, and finish off the hapless victim. When riding into battle against Men of Rohan, the Orcs would slash at their enemy from the backs of their mounts, using crude scimitars and knives. Often the agile creatures would lean down at the last moment, avoiding the spears of their foe, and slice at the bellies of the horses; once the warrior had tumbled to the ground, Warg and rider would compete to finish him off.

Weapons
Despite their being mounted, there is no real evidence to suggest that the Warg-riders favored either bows or spears, even though these would have been highly-effective weapons to use. It may be that the bucking motion of the Warg made it almost impossible to aim either weapon with any accuracy. Although the occasional bow or pike has been found, it appears that they generally carried crude, single-edged scimitars and sometimes also knives, which were used to slash at their enemies as they passed them. The scimitars were about two and a half feet long and lacked either guard or pommel; the handgrip was just a strip of leather wrapped around the tang.