After doing a little research I found that many consumers face the same problem I have with factory nuts. Looks like the factory nuts are carbon steel(?) with a chrome cap pressed onto them. The problem is that carbon steel (again?) starts to rust under the chrome cover over time. This causes the nut to swell, resulting in a change in the outer dimensions of the nut. It is almost impossible to remove the jam nuts if they are too loose. These clamping nuts from DPAccessories are solid and therefore have no swelling problems. In addition, DPAccessories nuts are much, much cheaper - go for it! I plan to buy more in the near future for another car that will end up with the same bloat problem. Good job DP accessories! Great product and service!