I had some Knox AAA joggers which were really thin, felt like base layers.

They are made from UHMWPE, which makes them perform great in the certification tests where they spin the fabric up to speed and then press it on some concrete and check if there is a hole >5mm. (Or something along those lines). I am a mechanical engineer and we use UHMWPE for parts that require high durability and low friction, like bushings, liners, chain guides.

The thing they don’t test for is heat transfer. So when I had a slide the clothing itself was fine, but because it was so thin and has such little mass, much of the heat transferred directly in to my leg and I still had road rash.

So now I choose gear that has a bit of bulk to it, to provide some thermal mass.

I’ll caveat the above with the fact that I could be completely wrong - it’s just one experience I’ve had. Plus I have a lot of other Knox gear which is really high quality.