If you have the 30mm blocks, you may also need to use the ride hieght/droop guage with that. The zero mark is set at 30mm on the ride hieght guage, so if the rear touched the guage at -1, the ride hieght is 29mm. Same for the front if the guage reads -3, ride hieght is 27mm. The blocks are used to set droop, not sure why Hudy choose 30mm for their base line number, but I am sure they have a reason.