I read many reviews on this product...even went to the Cabela's website and read reviews there.  I'm not sure what people are doing to crack these...they must be really WRENCHING on them with a phillips.  Mine are very snug and fit very well and I didn't need to really tighten a lot.  I think if you use common sense, you'll see they work and don't crack.  I have a topper, and these work well with that...I don't have to take these on and off.  They have been very convenient.