Had the Cervelo Caledonia 5 a week now and 4 rides in I’m extremely happy with the 30mm tires on the stock “Reserve “ wheels it comes with .
Used to 25mm Continentals with 95-100 PSI , I’m now running 71PSI .
Previous bike was a Cervelo R3 (2014) and this is a completely different ride, slightly heavier with the disc brakes.
Not sure what I was expecting when I purchased it , I did know I wanted larger tires but did not want to sacrifice speed and the bike definitely delivers .
Just Sayin…
I wonder how these “new” bikes are some sort of revelation?
I rode a 1x with 30’s, steel frame, drop bars, Brooks and a coaster brake all through grade school back in the day 
I still jack my pressures when riding road on my CX Spooky 80-90psi. It’s got 35mm CX tubulars on carbon DA’s. This bike is fast!
Loses nothing to my Giant on 25mm tubeless.
My preference is to ride tubulars on carbon wheels, also on my city commuter which has 28mm’s. Tubeless is very nice too.
For me, both tubeless and tubulars ride with better feel than equivalent clinchers in same size. so e.g a 25mm tubular = 28mm clincher for vibration and harshness isolation.
Living dangerously, you sound like a true rebel;)
A more interesting question (getting a good ride on 30s on the road isn’t a surprise) is what new terrain have you conquered with this bike you didn’t do previously with your road bike? I think the real benefit is you effectively have road bike speed with the option to do some rough roads or gravel in between without even thinking about it. I certainly have rides where I have pushed the limits of 23/25 tires on gravel or even light trails for a few miles, but would love to have a newer bike where I could run 28s or 30s so these little forays are a little less dodgy.
I bought a steel all roads bike ( Norco Section) this year and it came with 32 Hutchinson Sector tires. I have ridden road and what we have for sandy unpaved dirt and gravel roads with it and I love it. On the road it is not quite as quick as my Cervelo S3 with 25mm conti 4000sII’s and would not expect it to climb long climbs the same either but for everyday riding it has nearly replaced the S3. The fun is I can ride it nearly anywhere I want to go without hesitation even old logging roads as long as they are not to extreme. That is the best part all of the new options.
Living dangerously, you sound like a true rebel;)
A more interesting question (getting a good ride on 30s on the road isn’t a surprise) is what new terrain have you conquered with this bike you didn’t do previously with your road bike? I think the real benefit is you effectively have road bike speed with the option to do some rough roads or gravel in between without even thinking about it. I certainly have rides where I have pushed the limits of 23/25 tires on gravel or even light trails for a few miles, but would love to have a newer bike where I could run 28s or 30s so these little forays are a little less dodgy.
Ya I would be curious to know how much tire you can actually fit in the Caledonia. I don’t have a real gravel bike (yet), but I use a Fuji Gran Fondo endurance road bike. I can fit up to 38s (36s on wider rims). There isn’t enough clearance for really muddy conditions, but it is fine for dry conditions and damp gravel roads where you aren’t picking up tons of gooey mud. I have done CX and short-track gravel races on it and it has been good enough for my limited skills (the bike probably isn’t holding me back).
There seems to be a big grey area in the n-1 (or more) category and I would guess it comes down to tire clearance, especially when you consider bikes like the Ridley Kanzo. That thing looks about like a endurance road version of the Noah aero bike with the limitations of a smaller front chain ring, clearance up to 700x44, and no 650b option. Maybe the n-1 thing is a ruse and people will just end up owning 3 bikes that fit in the gravel-ish category.