polyester vs. nylon bottoms

…generally, yes, polyester is more breathable than nylon. There are multiple different types of weaves (often called different fabrics, actually) made of both types of fibers. What really matters here is that polyester is completely hydrophobic (the fibers themselves don't soak up any water due to their chemical composition, even though water gets into the interstices between them) while nylon is not (though still much better than most cotton weaves).

As far as finding polyester shorts, well, check your local Wal-Mart. In the athletics section (not sure about the women's department, but for sure and certain in the men's), they should have their Starter brand DriStar line. Check the tag (Wallyworld is notorious for horrible product mixing), but the majority of the shorts should be polyester. At least, they are around here. And they should be going on sale soon; it's getting to be fall, and fewer folks purchase shorts in the fall.

If you want to go up a level in cost, Sports Authority or the like will carry polyester athletic shorts as well. If you want a cargo short or such, I'm sure that REI or similar will also carry polyester shorts.

Really, if you want the quickest-drying shorts, look for a thin, loose, open weave on the shorts. The thinner the material, the better, and the more open the weave, the better. I can dry my polyester running shorts after swimming down here in humid FL in about an hour and an half as long as I'm not sitting down. YMMV, though.

(Edited for clarity.)

I haven't found polyester to be any more breathable than nylon. I think nylon is fine for breathability, if it's lightweight. I don't know how much REI Sahara pants weigh, but I assume they are in the 15 ounce range. Try some lightweight pants (~7 ounces) instead. Unfortunately there are few makers of lightweight nylon or polyester pants. Cloudweil used to make some nylon pants that weighed 7 ounces.

Rohan makes 7 ounce some polypropelene pants called the Men's Ether Trousers. Not sure about the durability. Polypropelene is generally weaker than polyester and nylon.

You might consider the pants that Dale found. I’ve bought several pairs I like them so much. Under 4 ounces. Under $20. What’s not to like?

here

from a search of the web:

"Nylon has by far the greatest moisture absorption (from 2% to 9%). Polypropylene absorbs none whatsoever, and polyesters typically absorb less than 1%."

another site I found said cotton can absorbe 27 times its weight in water.

I have REI pants that look similar but I purchased them 10 or so years ago and I don't know what they were called at the time. I have never had an issue with them holding water. once it stops raining that start drying. I have not noticed any difference between my pants and Capiene long johns in terms of drying time.

Nylon and polyester are plastics and neither are breathable when made into a solid sheat. For fabric the material is molded into thin strings which are woven together into fabric. The breathability of any fabric is going to depend mainly on the weave, how closly packed the fibers are, and what coatings, if any, that were applied to the fabric.

Did you use fabric softener on the pants? Fabric softeners often have oil in the ingredient list and can leave that on the fabric plugging the space betwen fabric fibers and increasing the amount of water the fabric absorbs Your pants may nead nothing more than a good cleaning with a cleaner without any fabric softeners or fragrances.

okay, nylon absorbs some water

Fabric from both nylon and polyester absorb a lot more water than that. Maybe the water coats the outside of the nylon or polyester fibers?

I wear nylon pants. They get wet from sweat where they're between pack and back. And maybe in general if I'm exercising a lot especially in hot weather. But then they dry out quickly.

Your experience with Sahara pants doesn't really make sense?

If nylon pants are not breathable enough by themselves, you might look at the eco mesh pants by Rail Riders. I think Ex Officieo makes some similar ones as well. Not as good as shorts but almost.

Look for polyester running shorts. There are also softshell shorts if you want something more durable and heavier. Sometimes the softshell material is nylon though.

Here's a comparison between a pair of nylon and and a pair of polyester wind pants made at Daryl Labs on 9/17/2012.

Dry Weight
Nylon 6.6 ounces
Poly 7.0 ounces

Weight when removed from washer at completion of spin cycle
Nylon 8.2 ounces
Poly 9.4 ounces

Weight after 1 hour on hanger inside house
Nylon 7.2 ounces
Poly 8 ounces

Weight after 2 hours on hanger inside house
Nylon 6.6 ounces
Poly 7.2 ounces

No animals were hurt during these tests.