shortening bag cups to lay

I finally found out why my front wont lay. The bag is bottoming out and i still have like 3/4" from laying on the skid plate. I bought jasons bolt in bag cups so theres no way they are in wrong. Who all had to cut down these cups to lay? Im running 225/40/18 and i have drop spindles. I didnt think i would need to do this with 18's but thats all thats holding me up. Oh yea and which cup should i cut down? the top or bottom? thanks