Hey Fascats. If you like me, you love to ride and you ALSO love your bike. Maybe I get a little too in the weeds of it sometimes, but it keeps me out of too much trouble. I’d love to know your thoughts on these two things:
1x vs 2x setup for gravel bikes?
700c vs 650b? or both?
ps. also…whenever I type ‘fascats’, it really wants to autocorrect to fascists—so if I call you a fascist…oops 
Good morning cj0hns -
I can’t speak to 650b vs 700c debate, but I do have a gravel bike in both 1x and 2x. I have the most miles on the 2x, which is actually my cross bike, but I put wider tires and some flared bars on it. I have logged a lot of gravel miles on that bike. The 1x bike is the new gravel bike I got in November, so I have less time on it, though enough for a good pulse. I do really like how clean 1x is and paired with a wide range cassette with Sram AXS it has been awesome. That being said, there has been a learning curve with 1x on the gravel bike (all my MTBs are 1x with no turning back) I have had to change my riding style a bit. With 2x I knew my gearing well enough to attack and hill and new when to just drop from big ring to small and maintain a clean cadence and transition. With the 1x this is more of a steady step down and then ramp back up on the other side of the hill. I am happy with both, but still not sure that I would claim either to be king at this point. On smoother gravel I think the 2x might win out, when it gets real gnarly and blown out the 1x fits the bill great.
I love geeking out on gear too, looking forward to the banter and weigh in from others.
Tim C
I’m a big fan of 1x. But I haven’t had a 2x bike in a long long time. While I understand that the closer gear ratios are helpful, I really like simplicity—two levers one goes up, one goes down. I’m just not clever enough to figure out when to move the rings upfront. Maybe it’s just a little too much time on the trails and not enough on the road. Nah, that can’t be it 
Never too much time off-road… I don’t really care about the tighter jumps between gears either. My area is so undulating in terrain that I usually shifted two at a time anyways on my 2x. I have definitely ridden terrain that caters to either though. It was a painstaking decision for me when I bought the new gravel bike to see if the 1x love would transfer from mountain to gravel. All and all, I would say the answer is purely preference, riding style, and terrain as they both have certain features that stand above the other.
Personally coming for the road I prefer the 2 x system. I like have the closer range and the ability to have a cadence that I am more comfortable at. I understand the benefits of a 1x system but I was never in a situation yet where its benefits out weigh a 2x system. However if and when that situation out come up I bet I would wish I had it.
Last year I actually used both 650 and 700c on our Cervelo bikes. If I was doing a standard gravel race I would use the 700c wheels. I believe they are a bit faster and carry more momentum. Also being larger tend to roll over objects easier.
However I used the 650b with wider tires often. I found it be really comfortable. I didn’t feel noticeable slower on them. I. could also take it over rougher terrain, like a mountain bike. I found this to be really enjoyable.
Whether you use 650b or 700c can come down to course or type of riding. I think it is good to have both options. I never thought I would use the 650b wheels once I got 700c but I found myself going back often.
We’re speaking the same language on wheels. I like 700 or so for fast gravel, but I also have a set of 650’s with tires similar to my xc bike for more rugged terrain (and bikepacking)…I also like that the 650s seem to add another gear for climbing!
Yeah I did an event last year that was like bikepacking through some gnarly terrain in the UP of Michigan. I loved having the 650bs with 48mm. Never once did I feel I needed more.