I PURCHASED THRUST SPROCKETS 15/45 COMBO WITHOUT CHAIN. I DID NOT REPLACE THE CHAIN AT THE TIME OF THE PURCHASE. SHOULD I REPLACE THE CHAIN/SPROCKETS THE SAME TIME? I LOVE THE WAY IT RIDES, SHOULD I MAKE THE 520 CONVERSION TO MAKE IT EASIER ON MY TRANSMISSION?

 

Always replace chain and sprockets together. An old chain will wear out new sprockets way fast, and vise-verse. As far as 520, sure. I didnt notice anything with it, but i geared it at the same time, so mostly in gearing. Most weight saving was in the aluminum rear sprocket as opposed to the steel one.