Just ruined my FOURTH SET of Milenco Quatro Levellers. I have tried everything, reversing up, standing start, running start, second gear start but the bottom 6" of gripper starts to sheer off and gets progressively worse until becoming useless after three or four uses. They are supposed to be suitable for up to 8 tons, we are 4 tons. I know some funsters swear by them having no problems at all. I have used Fiama Jumbo and Thule Jumbo levellers no problem but can't get the height. Contacted Milenco with photographs, receipt etc. and they suggested I had rocks and bricks under the levellers when using them which caused the problem! Ridiculous. We only use them on proper pitch surfaces of grass or gravel. Considered a fifth pair and somehow infilling the first 8" with a resin or styrofoam to just below the grip top to re-enforce them. Any sensible suggestions or alternative levellers welcomed!