I have cycling jerseys and recently purchased a poly t-shirt for hiking since I am hiking every Sunday and it's getting warm and the cotton t-shirt was feeling gross after a 7 mile, 1200 ft hike. I've worn it twice now and it makes a big difference. It doesn't even seem to get soaked like the cotton shirt did. It doesn't take much of a breeze to keep it dry. If you are biking in cotton and sweating a lot..... ew. I recommend a cheap athletic shirt. Marshall's, TJ Maxx, etc have a decent selection of these shirt for $10-15.