i did the drop axle and the disc brake conversion on my 49. I used the 5 on
5 1/2 rotors and now id like to swap them for 5 on 5 to match the front. Whats the best option for these rotors?

 

You might give a call to the vendor that you bought the adapter kit from and see what they say. With any amount of luck the spindle adapter is the same. The only other thing that may be different is the thickness of the spacers between the axle flange and the caliper bracket.

Bobby