I have a 2017 Sirrus Elite alloy disc brake model. It has the 2x9 Shimano Sora setup and it’s given me nothing but problems. I really want to go to a 1x12 setup.

I’ve been trying to figure out exactly what Groupset to get, looking at a Shimano 7100 series, SRAM Eagle NX or Rival1 setup… also if it’s drastically cheaper/less work to go 1x11… I’m not opposed. I know I’m looking at a new wheel for the 1x12 setup.

My big problem is I don’t know which bottom bracket I have and if I’m gonna need a new one? I’ve got a FSA Gossamer crank on there now.

If anyone can help me out with that, I’d appreciate it. Or can give me a run down of everything I need? I want to start buying parts on Amazon prime day, and then use this as a learning project. Will have a LBS look everything over once I’ve built it but I’m looking forward to tackling the project a bit at a time once I’ve got my parts sorted.

Thanks everyone.

https://99spokes.com/bikes/specializ...7/sirrus-elite

Flat bar, hydraulic brakes, Sora Derailleurs, and microshift Road Ratio trigger shifters, right?

what gearing range of 12 speed cassette are you contemplating?
what sort of riding do you do?

Yeah those are the specs.

I was thinking like 11-50 on the cassette. Not sure on the chainring yet… but figure most of the options I was looking at allow for swapping different chainrings onto it.

I do city/urban riding/commuting. One of the parks I enjoy riding (plus NYC’s Central Park occasionally) is hilly. I also would like to participate in group rides where there are a lot of road bikes.

Ebayt search: Sunrace CSMZ90 12sp Cassette, 11-50t - Black

i hear it fits on a shimano 8-9-10 HG style freehub .

if your Sirrus is like mine, a road width single crankset will work... or you can swap a different, larger chain ring onto the outer side of that gossamer for now... a 44 or 46 might be a good starting point for the ring...

i went 3x10 on mine, 46-36-24 HT2 MTB hollowtech... and an 11-32 on the back... Deore and XT shimano parts.
it's an older rim brake frame.

your Sora parts should have worked fine... i'd be suspect of the microshifters.. the ones i've worked on seem clunky, kinda vague..
any info on why things aren't happy on your bike ?

From day one (bought it in 2018) both fresh from lbs as well as after having a few different places do drive train adjustments I’ve had issues throwing chains. Or if I shift it’ll sort of shift but then bounce back to the gear I was trying to shift out of…

So I’d never use the smaller chain ring. Figured If I can’t use the smaller ring up front I might as well go with a setup that lets me avoid the extra parts but still lets me have good range on my gearing

Bottom bracket for current crank is Mega Exo 24MM This look like your crank

With that 2x crank, I'd go with a Shimano HG700 11-34 11 speed cassette and chain, 105 R7000 FD, GRX RX-810 or 105 R7000 GS RD, and Microshift Centos 11 flat bar shifters unless you can find Shimano RS700 pieces for a reasonable price. I have set up multiple bikes with this 11 speed stuff and it was easy and very reliable.