RE: too many options. . .
I didn't realize HK had gears; http://www.hobbyking.com/hobbyking/store/uh_listCategoriesAndProducts.asp?idCategory=305<di v>
</div><div>I also found these; http://www.rc-monster.com/search.php?pg=1&stext=5mm+pinion&sprice=&a mp;stype=&scat=40&sman=</div>