Speed ratings on tires are expressed in letters and are generally listed along with the load index for a tire after the size, for instance 245/40R18 93H. 93 is a load index and the H is the speed rating .â¦. What Does Z Mean On The Tires | Zr Speed Rated | Zr Rating. 1  Differences in Tire Speed Ratings Explained.
Effacement: Thinning of the cervix. In the last month of pregnancy the cervix will begin to stretch and thin. This is an indication that the lower portion of the uterus is getting prepared for delivery, as a thinner cervix dilates more easily. Your health care provider can check for effacement in the final two months of pregnancy.
Effacement is often expressed in percentages. At 0 percent effacement, the cervix is typically about 3 to 4 centimeters (cm) long, or very thick. Your cervix must be 100 percent effaced, or completely thinned out, before a vaginal delivery. Another of the early signs of labor is your cervix beginning to open (dilate). Your health care provider will measure the dilation in centimeters from zero to 10. At first, these cervical changes can be very slow. Once you're in active labor, expect to dilate more quickly.