Black Mountain frames are excellent quality- heat treated seamless double butted .8/.5/.8 tubing. The Fairdale is also heat treated seamless double butted tubing. I would bet it has the same butting profile too. The marketing for Fairdale is great and they really nailed the idea that their tubing is unique and custom, but it isnt. The custom drawn aspect is nothing new or unique.
Both frames are really great quality.
I compared the geometry for both frames and just didnt see much of a difference. 1cm chainstay difference, a few mm bottom bracket difference, a .5 degree frame geometry angle...but nothing that will make you faster on the Fairdale.
Remove the rack and bag. Thatll drop 3-4 pounds.
Get 28mm(which often measure 30mm) Continental GP4000sII tires for $80 overseas. Thatll drop 150g.
Get a Whiskey no7 carbon fork from Universal Cycles for $350. Thatll drop 550g.
You will have a bike thats 4.5-5.5 pounds lighter.
Get another headset(i assume you have a cane creek 40) and you can more easily swap between forks if you like.
Also look at wheelsets. $300-400 will get you a quality wheelset that could drop another 1 pound off your bike if your current wheelset is 2000g.
The Fairdale is really nice and if you want a new bike- go for it. I just offer this option up as an alternative since you clearly like your current bike and this would make it both lighter and faster. Itd be faster not just because of the weight savings, but also because the tires have less rolling resistance.
Fame to frame- you are a wash in my view. I have a BMC gravel frame, have looked into a road frame a dozen times, and have looked seriously at Fairdale many a time too- i just dont think there is something magical with a Fairdale that will make a rider faster when the Black Mountain can be built up to go fast for a lot less $. $500 spent for about 5 pounds saved and less rolling resistance.
Good news is you cant lose regardless of your decision. You have an awesome bike and you are looking to buy an awesome bike. Great problem to have!
Below is a pic of a current gen road frame with a Whiskey fork i pulled off of Varley's Black Mountain facebook page. I like the black fork with black components look.
