Plainsman

I have a 2 x 9 FSA AlphaDrive crankset, and I知 thinking of getting the Microshift Advent X group to go 1 x 10. Trying to not spend more than I have to so would like to keep the BB and crankarms/spider. My question is, if I can find a 30T outer ring in 96 BCD for 10 speed, can I simply drop the inner ring from my crankset and install the new outer, or is that a no-go due to chainline issues? Thanks for any advice.

Russ Roth

It will have slight chainline issues but probably not bad, a 1x crank should sit the chainring in the middle of the rear cogs while a 2x will optimally have the spider at the middle line. That spider though only takes up a couple mm which means you might have a touch more noise in the smallest cog but I've found the 10sp systems to be more flexible then the 9 and 8 speed stuff was, my old 8sp is really noisy cross chaining while when it was 2x10 the mtb wasn't noisy at all by comparison.

DrIsotope

I've never used a dedicated 1X crank on any of my 1X setups, and have never had a single issue with chainline. Worst case scenario, the chainring will have a straight chainline to the 4th cog and not the 5th. I've really started to think that the importance of chainline is generally overstated.

Plainsman

Great to hear! For your 1x conversions do usually do the same, just drop the small ring and replace the big?

dsbrantjr

Well, the chainline can only be "correct" on one cog of a cassette/freewheel anyway...

tomtomtom123

I've always wanted more gear range with closer spacing. I find it a disadvantage to drop a chainring with bigger spacing between cogs.

Plainsman

Good point!

DrIsotope

Yessir. Narrow-wide in the outer position, never had an issue-- and this is with 42T big cogs.

Plainsman

Perfect! Sounds just like what I have been contemplating!

cchmilar

Some of the narrow/wide manufacturers (RaceFace and WolfTooth I think) have guides for positioning of rings and chainline

Plainsman

I have one more question for you. Just found a 30T chainring, and I'm planning to pair that with the new Microshift Advent X 10 speed setup. I'm mostly a road bike guy, so not sure how to calculate capacity on a 1x setup for this derailleur. The cassette is a whopping 11-48. According to the specs, the Max Sprocket on the RD is 46-48T (so looks like I'm good), and the chain capacity lists as 41T. How are they measuring chain capacity for a 1x? I'm not exactly sure how to make the formula work with a 1x setup.

And I'm also guessing no issue mixing a Shimano SLX M7000 (SM-CRM70) chainring with an FSA AlphaDrive Crank, as long as they are both 4 bolt and 96 BCD?

Thanks!

https://www.microshift.com/en/product/rd-m6205am/

tomtomtom123

48-11=37
those are huge steps.

You'd have to check if the Shimano and FSA use the same asymmetrical bolt flange angle. If they're different then they won't be compatible.

Plainsman

Other than taking apart the crank and fitting the Shimano ring, is there a way to know from the specs?

DrIsotope

AFAIK, chain capacity isn't a concern with 1X, because there's no front shifting-- chain capacity or chain wrap is derived by subtracting the smallest cog from the largest (which in your case would be 48 - 11 = 37) and adding that to the difference between the front chainrings, which in your case would be, uhh, zero (30 - 30 = 0.) Your chain capacity would (I guess) be 37. So long as the RD can handle the big cog, it's fine. Unless your chainstays are reaaalllly long, I imagine your chain is going to be shorter than mine, as I run a 44T chainring with a 10-42 cassette, and have never had a single problem, ever.

cpach

The 1x chainrings offset to center the chainline, so you're good to go.

Plainsman

Thanks! Hadn稚 thought about that. I致e got this stock FSA AlphaDrive (double) 96 BCD crankset (square taper) on my bike that has hardly any miles on it, so I知 trying to re-use it. Found a guy selling a new/never mounted Shimano SLX M7000 30T ring (96 BCD) for $10 the other day, so I jumped on it hoping it would work. I had already used a gear calculator to determine a 30T was what I wanted.

Plainsman

Thanks Doc! For someone like me I知 now thinking this crank change and RD swap is going to be the easy part - mounting new hydro brake levers another story! YouTube videos on how to bleed brakes and the like, here I come!

tomtomtom123

These are proprietary angles meant to force you to buy their products. Whether the companies choose to use the same, they probably won't tell you. Either do a Google search to find out if someone tried it or test it yourself.