You need to find out if the rims are new style or old style Dymags. They are probably the new style since they are on a '99. With my last set of Dymags, a socket head type bolt passed completely throught the sprocket from the inside, or the backside, and threaded into a star shaped casting on the outside of the sprocket holding the sprocket and star casting together. Then the round head of the socket bolt rested in a steel sleeved rubber dounut pressed into the hub of the wheel. I doubt the sprocket is threaded. On the "old style" the sprocket was held on with a large wave washer and circlip which facilitated quick gearing changes if you were racing.
Howie
Yeah the new style is what i have. Sprocket specialist makes basically anything you want in the way of size and ton of options if you want to pay for em. Dymag said basically they dont do sprockets even though they come on their wheels, Talon finally got back to me and said they have them for 30 EU plus vat and shipping i don't know what that amounts to in US$, The SS sprocket is probably going to run me 80-90 $US
Not wrecked, the Rims are cast Magnesium