Originally Posted by JohnDThompson

Surly makes splined cogs that. it on the S3X hub. AFAIK, there is a 19T, 3/32" version available. Otherwise, the S3X driver is threaded for a standard track cog. If you have a 19T, 3/32" threaded cog you can use that if you put one of the splined SA spacers between the cog and the lockring.

eBay also has an abundance of inexpensive, splined 3/32" cogs:

http://www.ebay.com/sch/i.html?_odkw...at=0&_from=R40