Yesterday I installed my new X-ring chain and sprockets. When I was turning the wheel adjustment bolts in (to make the rear wheel forward) the threads became very tight. I ended up rounding off the 10mm bolt. I ordered replacement bolts online last night but I am wondering why they became tight all of a sudden. It took a lot of force to turn them in and I have never experienced that in the two + years of owning the bike. Any ideas why this happened? Do the bolts just thread into the swingarm? Anyone ever had them out or had to replace them?