Crank it, yes! While it depends on your application, but because they are stronger material, you can tighten them a lot! That tight seal secures much higher pressure than normal. But this does mean that you might have to tighten it more than you otherwise would. In household plumbing, like basins and taps, we recommend an extra 5% to 15% on torque settings. So if you set a torque wrench to 15Nm with standard neoprene, we would recommend tightening to between 15.8 - 17.2Nm. Trust us, they're not going anywhere!