So I looked at my bibshorts the other day and noticed that i'm getting rubbing/fraying on the material on 1 side only.

what can be the cause of this? Saddle too high? I've tried lowering it in the past but really didnt like how it felt.

I had this at one point and discovered that my saddle rails were slightly bent, causing one side of my sit bones to be slightly higher than the other. Also check that your cleats are equally positioned - unless one leg is longer than another

Also check to make sure that you're not rubbing on a flap for a seat bag.

+1

I have a stupidly designed Vaude saddle bag with the sharp side of the velcro on the seat post strap facing out.
It gnawed a hole in two tights before I'd figured out what was going on.

I had a seat cradle, that shredded a pair of shorts before I figured out what it was, when the factory paint rubbed away it left a metal burr exposed. I water sanded the front to a mirror finish and no problems since. Aero seat cradle btw

My saddles wear more on the left side than the right. I always just assumed that my legs were not symmetrical and never really worried too much about it. I haven't noticed that my shorts wear any differently on either side.

You might look into a leg length discrepancy. I rode forever in ignorance, always aware I could not sight down the center of my bike when i looked down but just figured that was what it was. Went to a PT for a different issue entirely. First thing she had me do was walk the length of the room away from her, turn and walk back. Her first words were that my right leg was shorter. Sent me home from that session with 1/2" lifts to put in my right shoes. She had me shim my right cleats out 1/2 the distance, 1/4"

Both were revelations. I stand straight now. I look down and the top tube blocks out the down tube. I sight down the center of the front wheel. Who knew?

Ben

I've had this happen with a couple pairs of shorts due to seat bag rubbing.

leg length discrepancy is another good one (I got this too and it's causing me knee issues). If one side chaffing is comorbid with one side knee pain then this might be a good place to look into.

most people's bodies are woefully asymmetrical. unless it's causing you pain or discomfort, i wouldn't worry about it, they are just shorts. they don't care.

A lot of great suggestions, above (leg length discrepancy, which is not uncommon; saddle wear, etc.), so I'll try to come up with something new. By any chance is the extra wear on the side of your dominant leg? If so, could be your pedal stroke is uneven. Just a thought.

really, i can't even beat an egg left-handed.

I removed the velcro seat post loop from mine. It didn't do anything useful, and the exposed velcro was not good for the legs. The bag stays in place just fine thanks to the rails attachment.

Seat/saddle bag velcro is the natural enemy of bib shorts. It is the only known natural bib short predator. It is a menace, and should be put down whenever encountered.

I have nothing against saddle bags. Because when I do, it's usually my shorts, and that's not good for them.