New build: all other things being equal (groupset, geometry, components, and aesthetics), if you had to choose between hydraulic disk brakes, or a lighter (by 1.5 lbs) bike with caliper brakes, which would be preferable?

Is it raining? What wheels am I running? How are the aesthetics equal (would the caliper bike have decorative rotors and the rotor bike have decorative calipers), and related, what style of frame and headset are we using, and what is the color scheme? What are the particular brakes? At what altitude is the 1.5lb difference measured, and where will I be riding the bike? What am I using the bike for (i.e. racing or solo riding or cooperative pacelining)? What tires are being used? Does the bike have full-length fenders? Is the bike just being used on the road, or is gnarly off-road descending in its future?

While I don't mind rim brakes, at this time I'd most likely go disc.

I would go disc...I value the wider range of tire sizes that it accommodates purely from a comfort perspective. I recently made this switch and ride 28c Schwalbe Pro Ones as daily drivers (31.7mm at widest section). Thru axle and flat-mount disc make removal and re-installation of the wheels a breeze - something I value given that I often travel with both wheels off.

On aesthetics, it depends on the specific frame...I really like the sparseness of the seat-stays on my Domane wherein there is no cross-brace where a traditional caliper would sit...I think it looks fantastic how the wheel/tire just lives inside the large gap:



For some more traditional (non-endurance frames), I can appreciate the aesthetics of the compactness of a direct-mount caliper brake.

I'd definitely go lighter. Braking has never been an issue, only tire traction.

I don't need disc brakes. Simple.

My current bike has caliper brakes, and I have no plans to change bikes any time soon, but I did test ride a hydraulic disk bike, and 1 easy finger stopping from the hoods is very nice. With calipers, Some descents have me squeezing pretty hard.

I would do it if money were no option...the weight penalty is not big in my mind...my bike weighs 22lbs, and I don't feel like I am hindered much on climbs.

for my road riding .... rim

Hydraulic disc. More tire clearance, lighter-effort braking, awesome modulation/feel, performance that doesn't diminish in foul weather, and it's easier (for me, at least) to justify nicer wheels because rims are no longer sacrificial.

I might be looking for a new touring frameset ... so discs for that.

Otherwise ... rim brakes. I already carry enough weight which doesn't help my performance.

Depends what the bike is for. Cyclocross? Discs. Road riding/racing? Lighter.

pretty much where i'm quickly getting to.

If I could have gotten a disc brake copy of my bike I would have.

1.5 pounds is a lot! Go for the lighter setup

Rim. TRP or EEbrakes improvement over RED or DA on carbon? Anyone have experience?

Just had to make this decision when purchasing my S-Works. I went with caliper brakes. Lighter weight, more wheel choices, I don't ride it in the rain (well... not by choice) but mostly, where I live it's pretty flat. If I were riding in mountain areas, I would have chosen disk. My gravel bike is disk and I've had other disk bikes. I have nothing against disks, but I also have nothing against calipers.

Unless you're planning on running tires wider than 28mm, caliper setup every day.

Modern road calipers stop just fine, and 1.5lbs is a lot of weight.

If you're going to use the bike on dirt/gravel roads, or are doing loaded touring and want wider than 28mm tires, then discs become a viable option.

You can run 28 mm tires with caliper brakes.

GOOD disc brakes because then I can get carbon disc wheels. Not a fan of carbon/rim setups. Entry level disc brakes are terrible, so caliper would be good in that case.

So I can add 1.5 lbs to the bike and increase its aerodynamic drag, so I can then buy expensive carbon disc wheels, so I can decrease the weight of the bike 1/2 a pound, from the 1.5 lbs I added, and decrease the aerodynamic drag with the deep sectioned carbon rims to offset the drag I added with the discs.

Makes sense to me.

Exactly. But. Carbon wheels no doubt make ride quality better I just don't like using rim brakes on CF wheels. Doesn't work.

I haven't experienced that. Box sectioned aluminum rims are likely to give a nicer ride than deep sectioned CF rims, if ride quality is your major concern.

5lbs change in air pressure is going to make a bigger difference than rim material.

and in my experience right pads, right rims, caliper brakes work well on CF rims.

What testing has been done with disc vs caliper brakes in a wind tunnel for drag? Legitimate question and I have no intent to engage in this debate with you again. 2 years more riding experience now and I have to think I pretty much agree with you on this matter now.

Can everything but weight be equal now? Last I considered a disc road bike price was very different between disc and caliper brakes. I'd be surprised to be able to buy a both an Ultegra caliper and Ultegra disc bikes for the same price. I would have expect that to be upwards of a $500 difference.

Actually, no.

Note I said 28c tires - not 28mm. 28c Continental GP4000IIs measure 30mm...Schwalbe Pro Ones measure 31.7mm.

I originally bought the direct-mount caliper of the Domane SLR. I needed to use the barrel adjusters to get anywhere close to clearing the tire through the caliper for quick wheel removal (note my original comment re: wheel removal). It was on this basis that I switched out to a disc version. I transport my bike regularly with the wheels removed. Discs free me up from all of the hassle of clearance issues.