I have just fitted a new four arm spider to my 7 year old middleburn RS7s. This replaces the 5 arm one and I've replaced it specifically to run a Renthal SR4 single ring. The problem I have is that the new spider does not have a recess for the lock ring which makes it foul on the shoulder of my SKF square taper bottom bracket effectively locking the crank against it. All this gear should be compatible as middleburn recommend the SKF B/B for this crank. Any one got any ideas how to overcome this one?