trigger shifter ?

[malcolm]

Just finished assembling my first ever mtn bike. It's only taken about two years to finish. Anyway I've got a question.

It's sram X9 and the rear shifts perfectly the front however shifts fine from small to middle to large but in the other direction it goes straight from the big to the little ring. I've built up a ton of bikes but few triples and zero mtn bikes. I've not messed with it much but was wondering is this a tension/barrel adjuster problem or does it lie elsewhere.
Thanks

[Liberace]

It sounds like you have too much tension. I would loosen the front derailleur cable. Pull the cable by hand and tighten. See if it shifts properly then.

Also remember not to adjust the limit screws when the derailleur is cabled. This usually causes a lot of problems.

[malcolm]

I set the limits by hand with the cable undone and pulled it hand tight, maybe I don't know my own strength, I'll redo it and see what happens.thx

[cromo900]

Shouldn't be a limit screw issue as you're aiming for a middle ring not affected by either of those limit screws. If it's dropping from the big ring all the way to the little ring, then it's losing too much tension, skipping all the way over the middle to the little, i.e. doesn't have enough cable tension. I'm also thinking it's rotated such that the back of the derailleur is a little too far inboard. And the inside plate is shifting the chain up to bigger rings fine, even with not enough tension, because it catches the chain early due to being rotated out. And on down shift, the opposite happens: outside plate catches the chain early, but with too little cable tension, drops the chain all the way down.

[malcolm]

cage parallel with the rings

[Liberace]

Try an 1/8 left turn of the limit screws. This gives the cable a tad more room for even tension through the shifting throws.

[oliver1850]

I admit to not having used SRAM MTB shifters, but it sounds like a shifter issue to me. It sounds like one click takes it from the big to the small ring. Will the shifter click again after that? Pull on the cable when hitting the trigger and see. If it doesn't release more cable, I'd guess there's something wrong with the shifter. If it does release more cable, it's a cable tension issue.