I have always used long cage but it is obvious that medium length cage will be less liable to trail hits. So what is the downside of the shorter cage, more force required for shifts?

Nope. No disadvantage at all.

They’re not recommended it you are running a triple chainset, not enough range

I use medium cage on all three of my bikes. Fine with triple chain set just don’t use both the larger and smaller gears at the same time, which you don’t need to anyway.

Kev

Yep, same as Kev here. Medium ok on a triple unless you go big/big, at which point your chain seizes. No biggie, I’m happy sticking with a medium mech.

So you have to remember not to accidentally go into the big/big combination 😕

You shouldn’t use the big/big combination anyway 😛 OR the small/small for that matter – chain is at too much of an angle.

Its a good habit to get into avoiding that combo anyway, it looks nasty, sounds nasty and makes for an unhappy chain.

Thats why I leave the indicators on my shifters, wouldn’t trust myself not to end up in that gear without realising.

Edit: d’oh! beaten to it.

well yeah, obviously 🙂 I’ve done it a couple of times though, thinking I was in middle when I was actually in the big ring.

yeah, I’ve done it on night rides when I couldn’t see my indicators and had gotten confused. It wasn’t pretty because not only was I running a medium cage mech, I’d cut my chain as short as possible. thankfully steel mech hangers twist back easily… 😳

Alright so as I only use 2 chainrings I will try out a medium.
Ta
OP

Oh you’ll be fine with a 2 chainring setup

With a 2 chainring setup, as long as you’ve not got a massive gap between them (say anything over 12T gap), you can run a short cage mech… Which brings even more benefits!

I’ve used a short cage XTR with an 11-32 9spd cassette and 24/36 rings up front for a while, on a full sus bike with a bit of chain stretch (not massive though) and it has all been fine. In fact probably the best gear setup I’ve owned!

Always have used a short (or medium as the shadow call them) cage mech with triple chainrings. Set the chain length so it will fit big/big and you have no risk.
In the granny ring the chain will be getting a bit sloppy by 6th sprocket, but then do you ever go further down the cassette than that in the granny ring? The ratio has usually started to overlap with middle ring /1st sprocket.
Suppose its a personal thing.