Originally Posted by
Branko D
Pro teams juggle a lot of bikes, and keeping sealant fresh in all of them is too much logistically. Hence they use tubeless liners a lot, spare bikes / wheelsets might not have any sealant bar the minimum just to fit the tire.
They don't cause any extra rolling resistance, add minimal weight and enable you to ride with a puncture.
EF's team mechanic discussed this on a podcast a few years ago and said they were running inserts with minimal sealant, but I thought I had read/heard that they stopped using the inserts because riders didn't like how the tires felt. I don't think this is common among the pro peloton, but maybe you have more info than I do on this topic.
I don't really see how sealant would be a logistical problem. I doubt they keep tires on wheels long enough for sealant to dry out. It's not like they mount up a bunch of wheels in the spring and then run them all season - these guys are likely running brand new tires for every race.