All my MTB trousers are a bit loose and flappy so I think the pads would rub when pedaling and also move too easily in a crash.  Could work well in something like that new Fox speedsuit though

also move too easily in a crash.

stand alone kneepads and shorts must be equally bad or worse in this regard, as the pad can get twisted all the way round if you pull hard enough. trousers are limited by the material of the upper and lower leg preventing rotation.

neither would be as good as trousers over kneepads but thats very hot/sweaty in summer and requires quite a loose trouser fit.

My Revolution Race trousers have a pocket type thing to take a knee pad. Never tried it but probs more suited to kneeling type activities* than falling off a bike at speed.

*Praying, dogging, gardening, being sick etc.

I use Dainese Trailknit Pro Armour base layer trousers for mountain biking and for round town on the motorbike under my jeans. On the mountain bike I actually wear them under shorts most of the time, but they work equally well under trousers. The good thing is that the protection stays in place and you don’t get any chaffing like you do with some knee pads. A bit spendy, but worth it for me, from memory I paid a lot less than RRP, though it was a few years ago!

https://www.dainese.com/gb/en/trailknit-pro-armor-pants-204910018.html

armoured under shorts and knee pads, or armoured under leggings i think i've seen

The good thing is that the protection stays in place and you don’t get any chaffing like you do with some knee pads

They look like a step in the right direction, something like that but with lighter weight and meshed material for riding in would be great… perhaps even with bib straps and chamois so you don’t have to double up on your under garments.

Always wondered this.

I used some trousers in my old job which had kneepads.

Hard shell outer, foam inner that sat in a pocket.

Velcro tab behind the knee to secure with drawcord in pocket allowed the trousers to be adjusted so that pad sat in the correct place.

Stretch panels around the knee and waist to enable everything to stay in place when under tension from use and load.

Not sure how they'd fare in a crash but worked a charm for my role.

Let's also talk about pocket placement and why the hell they insist on putting pockets in the fold of your hip/thigh too?

Isn't the issue here that once a trouser is tight enough to hold a pad in place, it's basically a pair of heavy duty tights rather than a trouser. Or maybe a sort of hybrid trouser / tight with very snug knees. I suspect it'd look a bit odd, which is probably why no-one's done it?

Given the average age round this forum, i thought you were referring to incontinence pads.

I have no issues wearing IXS Flow pads under my fairly slim fitting On One trousers tbh

Pads fit great under trews… but if there’s a way to keep protection in place without rubber grippers or strapping… I’d be all for it. Under garbs which hold pads in place looks an interesting option.

MTB trousers with built-in D30 inserts sound like a dream, right? But here's the thing – the MTB terrain is way more dynamic than road riding. Trails can throw unexpected twists and turns, and having rigid padding might limit your flexibility. Plus, the weight and bulkiness could affect your agility on the bike.

I think they’ll start appearing in the next few years now that D30 padding shaping and design has improved (better ergonomics)and race kit has got tighter (so the pads won’t move around as much). They’d be much more comfy than silicone grippers and straps. As long as they’re removable for washing.

My guess is they won't appear.
Floating pads are not a good idea on something you pedal and get sweaty in.

Oooh, the chafe 😳

Also, catering for all different leg lengths in order to give correct placement in a bit of a small market would not make economic sense.

Also, crash and you've ripped and ruined a probably very expensive pair of trousers instead of just scuffed some pads.
Putting a material on the outside that would resist that would make them very rigid.

All kinds of a bad idea essentially.

I was thinking more for DH rather than trail riding where they’re pretty much wearing skintight clothes now. So there won’t be any worries about pedalling in them for hours or getting sweaty. More race specific stuff