Upgrade from Shimano 2x9 to Sram NX 1x12...

[Red Bird]

If it's like this one, then the LBS is talking out it's ass.

 

 

 

Stick the single ring where the middle blade goes, get some shorter chainring bolts and bob's your mother's brother.

 

It is a dual chainring crank. Here is a pic. I can’t think what the problem would be. I have a 38/24 combination and I want to put a 36 on. 104 diameter compatible. Maybe I must just invest in all the tools to do the job myself.

[Captain Fastbastard Mayhem]

yeah, it'll be fine. If it's a normal 104bcd then there's no issue at all. 

[Allrounder]

It is a dual chainring crank. Here is a pic. I can’t think what the problem would be. I have a 38/24 combination and I want to put a 36 on. 104 diameter compatible. Maybe I must just invest in all the tools to do the job myself.

I have start doing it a few months ago. The tools are more or less what my LBS asks per visit. And then Parktool has a great channel showing you how to do things. 

[Red Bird]

It turns out the BCD is 101. WTF FSA? They don’t make them anymore so I am gonna try the existing 38t chainring and remove 24t. Gear ratio difference won’t be significant as I have only used granny gear on two occasions and only use the one next to that more often.

[Red Bird]

So I finally got to test-ride new drivetrain.  Not a moment of regret!!  The 2x system was mentally exhausting jumping up and down between the chainrings and never being able to compensate on the cassette for the big drop in ratio (legs always spinning out).  Goodbye to chain suck - chain actually got stuck between FD and chainring and I had to dismount the FD to get the chain unstuck.  Now I could move the dropper post to the left side, easier to reach, which I have to get used to... I was still grabbing for it on the right side yesterday.  And no more noise!! 

 

There were some hiccups though.  This one specific FSA crank is only compatible with itself, so the LBS said I need a new crank.  No money for that at the moment, so they found a different solution - a direct mount chainring.  Thankfully the crank is compatible with cSixx Cannondale.  They had to cut off the existing spider, which was a bit more of a cost, but still cheaper than a new crank and definitely worth it.