Going to try MTB again after a 10 year break. I’ve got plenty of bib shorts for road biking and tri shorts for triathlon. If I’m successful at this venture I’m sure I’ll be doing longer rides and am looking for a short or bib that will be comfortable for hours of riding, holds up well to rips and tears, and is functional (I read a post that suggested not wearing your good road bibs because you will probably end up falling and tearing them). What are the “best” shorts for MTB (trail style riding)?
Been there - done that. I now wear my cycling bib shorts with whatever MTB shorts I like. The padded MTB underwear shorts have low quality padding and tend to have thick cloth, making them hot.
You shouldn’t tear your bib shorts because your MTB shorts and shirt should prevent that.
As for shorts, wear something long to help protect your thighs. Depending on where you ride, you may be hitting random tree branches and cacti. The less exposed skin the better.
For really technical riding, especially with big descents, I go full safety gear with knee pads, elbow pads, and a full face helmet. I’ve gotten away with a few face plants with a regular helmet so I wear the full face when in doubt now.
Now if we’re talking XC style riding / racing, then you can wear your typical cycling / triathlon kit.
No help here but just want to say it’s not a good mountain bike ride unless you come off at least once an hour.
I went out this morning on my first ride of my new FS Stumpjumper. I wore an old pair of DeSoto 400 bibs. I rode for a little more than 2 hours, mostly single track, with a few short breaks. I forgot how much you move around the saddle on a MTB and I my butt felt fine on this new saddle with the bibs. And maybe that’s because of the dropper post. I never have ridden with one and I absolutely love this feature. The only thing that really bothered me were my hands. I had a death grip on the bars in the gnarly stuff and they were going numb at times. I hope I’ll learn to relax them with some more saddle time. I’ll probably continue to wear the old Desoto bibs until I find some MTB shorts I like.
I’m another who wears bib shirts then a more robust baggy outer mountain biking short.
That protects the nice bibs in a crash, and also from all the shuffling around in the saddle + from the grit and dirt if you ride where it’s wet.
Also in a crash it helps the friction happen between the baggy short and the bibs, rather than your skin.
I only armour up properly when in the Alps or at a bike park (robocop style + full face helmet).
But some soft knee pads are a wise move all year round - plenty comfy enough for regular trail riding. I’ve been using some 661’s (Kyle Strait’ model) with a hard insert for years inc on all day rides. Finally knackered them after about 10 years use. Changed to some alternative knee pads that are soft and flexible with a D30 insert - soft to bend but stiffens in an impact (it’s a thixotropic material).
https://sixsixone.com/products/dbo-knee
Look after your knees!
I have a number of pairs, none of which I’m really crazy about. The kind with the integrated bike shorts that are connected to the outer shorts seem to be the ones I like the least. Maybe just buy a pair of unlined and get some of those inexpensive padded under shorts or just wear your bibs underneath them.
I don’t like the way that they catch on the seat or stick to my legs when I get sweaty.
For a training ride I definitely try to ride in such a way that I don’t fall off. You can hurt yourself doing that or come flying around a corner and run into a hiker.
My number 1 priority is to not fall or crash (hands still hurt from death grip). I realized today on my first ride that I was foolish to think getting off the roads and on the trails was going to be safer 
I normally ride my mountain bike with my Desoto Mobious shorts or whatever else i may use on the road.
Nothing special about any of my shorts
My number 1 priority is to not fall or crash (hands still hurt from death grip). I realized today on my first ride that I was foolish to think getting off the roads and on the trails was going to be safer
I started shifting a lot more of my time to off-road riding because of concerns about cars. So then I lacerated my kidney on a rock and spent a week in the hospital and 6 months off exercise. Oops.
I am a big fan of Zoic mountain biking shorts, have some Fox rangers as well.
I don’t wear spandex on a trail, just doesn’t feel right to me. Give me some comfy shorts and baggy shirts my Ibis and some nice single track.
I’ve got some Endura singletrack lite and waterproof over the knee Endura MT500 or Humvee (not sure which) so that covers the seasons and they both use the same clip-in liners that I’ve got 3 pairs of.
Have had excellent success with Pearl Izumi and Fox. Have a pair of PI shorts with integrated pad that are great for longer rides. Also, have some “cargo†bibs from PI that have pockets that I wear Fox (durable) shorts over and the wear lightweight 3/4 sleeve no zip jersey. POC makes some of favorite kit as well but kind of hard to get at times in states.
I just wear my road kit, even if that makes me look less cool than other riders.
I like my Fox’s better than my Zoics, only because the Zoics have lost their elasticity in the waistband - they are lighter than Fox but seem less durable. On the flipside I just replaced my Fox padded undershorts (hip, thigh, tailbone padding, etc) with new Zoics for the same reason, and the Zoic undershorts are fantastic.
Like others have posted, just wear whatever tri shorts or bibs you have with a proper pair of mountain bike shorts over the top (Fox, POC, Zoic etc). Those shorts are made of a fairly indestructible yet lightweight material, which you’ll need for protection when you inevitably come off your bike.