The Schallers use a smaller diameter screw and should screw in without trouble. They may be a little deeper than the stock ones. I have moved on from Schallers though. Had too may troubles with them. I use the Dunlops now with better success. They do have a slightly larger diameter but on my Spectors I don't think I had to open. The holes up to get them in. You could of course if they are too hard to turn. If they are that difficult do not force them, you don't want to break the screw. That would be a much bigger problem. Try a little soap on the threads before you install them, it will help them turn easier.