Here's the thing: tire size and pressure does more to change (negatively or positively) the "comfort" of your bicycle than your Cervelo R5 vs. S5 choice (or most other similar-ish framed carbon bicycles).
There's been plenty of reading to be had about this subject, but it does not honestly seem like the average customer is aware of such things. Bike shops do very little to help explain this as well (unless you're at Inside Out Sports, obviously).
Without going into too much detail and while still providing you with an engaging user experience, if you would like to discover this in more detail for yourself, here are some links:
So you're welcome to simply take my word for it, which I guess most will do given the volume of data and science that is presented above me...or you can go read all of those.
Here are some handy quotes, for those that wish for an expedited experience:
"Carbon Vs Steel Similar Geometry Custom Frames: 4psi"
What the above is saying that you can account for the different in comfort/compliance between those two things listed (carbon frame vs. steel frame, similar geometry) by changing tire pressure by as little as 4psi.
4psi!! That's huge! Or, maybe huge isn't the right word. That's "incredible" seems to flow better with the tone that this has in my head.
"No other single component affects the comfort, handling and efficiency of a bicycle like the tires. Tires are the sole connection to the ground, they are the sole transmitter of drive force to propel the cyclist forward, and they are the sole means of gripping the road during cornering. They are the most dominant spring in the bike/rider system which means that more than anything else, they control comfort. They are the sole component which will (ideally) ever have to resist the abrasive contact of asphalt, concrete or gravel with minimal damage."
I think that puts it pretty succinctly.
"The initial design of this test was to show that larger diameter tires are actually Stiffer/Less Comfortable when inflated to the same pressure."
i.e. don't pump those b***** up so high!
"What we can say is that all those people who feel their larger tires are more comfortable, you may be correct for bumps smaller than 8mm radius...we could not measure that, so it is hard to know, but for larger radii, you are best to lower your air pressure a bit to truly take advantage of the larger tire widths.
- Nicer tires (MUCH nicer tires) that are more supple and essentially have zero puncture resistance
- Nicer tubes; latex tubes can actually - according to some - make a perceivable difference in ride quality
- Perception bias: I WANT these wheels to feel better, so - naturally - they do!
- Pump inaccuracy: I always use the same pump, but most pumps actually have a pretty huge error margin. Mine is pretty nice (Lezyne Digital Drive and it gives me an actual digital PSI reading, which is nice) but I have no idea if it's accurate or not as I haven't ponied up for a tire pressure gauge.
Update on 2/22/2017
I've now had these wheels for quite some time now. Since July of 2016 I have put a few thousand miles on these wheels and only recently swapped tires for some 700x25 GP4000s II's. I never got a single flat (ok that's not true, I got one flat but it was because I slammed into a pothole and my tube got pinched), it was just time to replace the tires, especially the rear one, as the cuts had started accumulating beyond an "I'm comfortable with those for 100+ mile rides" measurement.
I have to say that I remain very impressed. Such a low-cost wheelset remaining true and bombroof even hitting some pretty crazy potholes and cracks is quite an achievement.