Q. Why do people tie their shoelaces on Shabbat when they are wet as when it rains or they walked on snow. Is that not a case of schita or squeezing out the water absorbed in the shoelaces?
Although, one may argue that this is a case of eino miskavein or not having any intent on squeezing out the water, but it is clearly a certainty that it will happen (psik reisha) and also he is glad to be wearing shoelaces that are at least not soaking in water (nicha lei), so why is it not prohibited?
A. Shoelaces have historically been made of materials like leather, hemp, or cotton—typical rope making materials. However, advances in the production of synthetic fibers like nylon and polyester and elastics have made a variety of shoelaces possible. Modern shoelaces often incorporate various synthetic fibers. (From Wikipedia).
Horav Shlomo Miller’s Shlit’a opinion is since it is likely or at least possible that the shoelaces involved may be made or contain synthetic fibers that do not absorb water, it is not a certainty or a p’sik reisha that one will be squeezing water when tying them.
When the above is not the case, the Rov added, that one should indeed be careful to tie them lightly, avoiding possible s’chita.
To also avoid other shailos as tying knots on Shabbos, it may be preferable to use shoes using Velcro or other types of modern elastic ties.
One may add that this type of squeezing is likely considered to be an unusual way of s’chita, and therefore one may be more lenient when there is no intention or need to dry the shoelaces, since they will likely become soon wet again.
Rabbi A. Bartfeld as advised by Horav Shlomo Miller and Horav Aharon Miller Shlit’a