Did I completely miss this? The German Tour magazine did a big wind tunnel test with most of the new disc aero road bikes and compared them to the rim brake predecessors. Basically only the new Cannondale is reasonably fast in comparison to the rim brake models and the weight difference doesn’t favor these bikes either.
I saw the results in the thread at Weight Weenies.
I can’t actually find the thread, but I did find the some additional test results that include the Pinarello F10
Am I missing something? I do not see comparisons of a disc brake bike with it’s rim-brake predecessor… They are totally different models. And I do not see any Cannondales. Is the link correct? This just shows that aero bikes are almost always faster than light bikes.
Here’s the thread https://weightweenies.starbike.com/forum/viewtopic.php?f=3&t=154692
There are only screenshots of the article which appears to be in German. One of the posts summarizes the results…
All tested at 45kph:
2019 Cannondale SystemSix Disc - 203w
2016 Trek Madone - 204w
2016 Specialized Venge ViAS - 204w
2016 Cervelo S5 - 205w
2016 Felt AR FRD - 205w
2019 Cervelo S5 Disc - 206w
2016 Canyon Aeroad - 208w
2019 Specialized Venge Disc - 208w
2016 Giant Propel Advanced SL - 210w
2016 Scott Foil Premium - 211w
2016 BMC Time Machine - 211w
2016 Look 795 - 212w
2019 Trek Madone Disc - 212w
2019 Ridley Noah Fast Disc - 213w
I’ve had my eye on a SystemSix since they were released, such a beautiful bike. This pretty much seals it for me when the time comes to upgrade the roadie!
An ultegra di2 system six is $10k in Canada.
Uggh.
That link is to last years test. I’ve been checking the Tour site regularly in the hope they’ll post the drag curves for the Jan 2019 test too. Tour are good at collecting data and no good at analysing it.
The data that GD28 posted is from the latest test
2016 Trek Madone - 204w
2019 Trek Madone Disc - 212w
2016 Specialized Venge ViAS - 204w
2019 Specialized Venge Disc - 208w
2016 Cervelo S5 - 205w
2019 Cervelo S5 Disc - 206w
So Cervelo went to all that effort with the S5 bars just to compensate for losses elsewhere.
Wow, 8 watt loss for the Trek. Where’s BryanD??
Right here and still laughing at you people holding on to rim brakes. A bike is a system of parts, not everything is about aero.
Interesting reading and responses from people.
Yes there are many pages on the weight weenie forum on this, should I cut and paste them all here? (sarc).
I concluded buy the bike that motivates you the most to go ride, within your budget and have fun.
It would be nice to try 3-4 of the top ranked to see which one rides the best for you.
Rob
Right here and still laughing at you people holding on to rim brakes. A bike is a system of parts, not everything is about aero.
That is certainly true, but I do not know if it is relevant to the discussion…
I don’t care if it’s relevant.
Right here and still laughing at you people holding on to rim brakes. A bike is a system of parts, not everything is about aero.
You’re right…they’re significantly heavier too 
I was wondering when you and the rim brake mafia would come back.
I will add that when you have two bikes, one disc, and one not… the differences in braking power and modulation are jarring when you switch between them.
Also, framesets are not the whole package. Rim shapes can be made more aero without a brake track, and tire size options more most road/TT bikes can now go up to 30C on a lot of disc bikes.
Wasn’t it the color of a bike that makes the difference in a journal ??
I will add that when you have two bikes, one disc, and one not… the differences in braking power and modulation are jarring when you switch between them.
…you’re doing the “and one not” wrong then.
Rim shapes can be made more aero without a brake track
…wishful speculation that hasn’t been shown to be true in practice
and tire size options more most road/TT bikes can now go up to 30C on a lot of disc bikes.
Huh…I wonder how my bike with rim brakes can fit tires measuring 30mm?..oh yeah, that’s not a brake technology issue actually, it’s a frame and caliper configuration issue :-/
That link is to last years test. I’ve been checking the Tour site regularly in the hope they’ll post the drag curves for the Jan 2019 test too. Tour are good at collecting data and no good at analysing it.
The data that GD28 posted is from the latest test
2016 Trek Madone - 204w
2019 Trek Madone Disc - 212w
2016 Specialized Venge ViAS - 204w
2019 Specialized Venge Disc - 208w
2016 Cervelo S5 - 205w
2019 Cervelo S5 Disc - 206w
So Cervelo went to all that effort with the S5 bars just to compensate for losses elsewhere.
I think the really odd thing is Trek making design decisions that basically “detuned” their latest rim brake Madone to make it slower than their previous version…seemingly just so it wouldn’t be faster than their disc Madone :-/
I will add that when you have two bikes, one disc, and one not… the differences in braking power and modulation are jarring when you switch between them.
Also, framesets are not the whole package. Rim shapes can be made more aero without a brake track, and tire size options more most road/TT bikes can now go up to 30C on a lot of disc bikes.
It’s not worth saying anything else in this thread. It will just turn into the rants of one man against an industry.
Allrighty then, I’ll be filing down my chainstays tonight.
Tom A isn’t the only one to pass on disc brakes.
Tom A isn’t the only one to pass on disc brakes.
To be fair, I don’t “pass” on them in all applications…just inappropriate/redundant ones
.