Originally Posted by airborneranger
Pretty much I'm looking for the biggest and smallest diff and center gear.
old schumacher diff pulleys were 30T, but they used 4mm balls. on the large side, the corally pulleys are probably your best shot. the losi ones have the balls too close to the center and as a result, don't last as long.
15t was common early on; hpi, tamiya, etc. on the large side, losi has this covered with their 23t.
keep in mind that if you expand your search to nitro cars, you can get just about anything you want. they use way more pulleys, and have all sorts of ratio options due to the over/under drive of the front/rear wheel diameters.
you can also buy pulleys here: www.york-ind.com
(there are many others).