Genuine benefit from aero frameset with all else being equal??

[AC427]

Hey guys,

New member here with a question for those with real world data of all things high speed. Aroad frames - Is there really a significant enough difference to justify a purchase? I've searched all over and cannot find anywhere that someone has tested the difference in the frame alone, there are always other components on the test bikes that do not make it a fair comparrison.

Here's the deal - My main bike is an open mold carbon gravel bike, road geometry but obviously big clearances in the fork & rear triange. I love this thing. Second bike is a Madone 5.9. Not quite in the aero frame category, but is supposed to have good aero benefits. Both biks are set up te same position wise - actually, the gravel bike is currently 10mm lower at the stem. Without wheels, both bikes weigh in practically the same at 12.5lbs. There is no doubt whatsoever that i am far quicker on the madone (2-3mph) at the same 300W power. Terrain is dead flat, group rides are single paceline & sit between 24-35mph constant.

The frames are both really stiff so nothing between them out of the saddle in regards to power transfer. HUGE difference in wheels though. Madone has 50mm Aeolus 5 carbon clinchers with 25mm pro-1's tubeless, Gravle bike has Stans No-Tubes Grail and 28mm S-Works tubeless. Much hevier - i'm giving away 500g right off the bat.

The wheels are clearly the big issue, or seems so to me. Madone is QR and the other is Thru axle so i'm unable to do a direct comparrison using the same wheelsets. I can see wind tunnel examples of aero frames, but is that gain really important at club riding level? What i'm getting at here, is most if not almost all of the gain from the wheelset alone, and the larger frontal area of the gravel bike negligable? Does a nice compareable deep section wheelset make both bikes equal at this level? I don't care too much for the Madone, and really love riding the gravel bike - but getting spat out of the back of the group and finishing solo is no fun, and that happens every time i'm not on the Madone. I'd like to see real world numbers from anyone thats done an aero frameset swap and kept all the other components the same where possible, especialy if you train with a PM as a placebo effect is not uncommon.

Cheers!

[wingguy]

Is the gearing the same on both? Chainring size and cassette range?

No frame change is worth 3mph on the flat - and besides getting spat from a paceline on that terrain is more about the effort taken responding to changes in pace than the aero side. If the gaps keep opening you'll get spat eventually even on the most aero bike, if you can keep closer on the wheel you'll stay in on a round tubed bike.

[RyanH]

You're probably looking for this thread:

https://weightweenies.starbike.com/foru ... p?t=139992

TL;dr:
1) Keeping everything constant is actually quite difficult.
2) There is a benefit to an aero frame. If I recall correctly, it was 9w at 300w between the Foil and the R5ca. R5ca had a slightly better position so the actual difference would or should have been higher. Even with the low conservative number, it's still 3%. People pay quite a lot for those ceramic speed goodies that only claim to save 0.25% or whatever it is.

[AC427]

Gearing is almost the same, 11-25 vs 11-28. I do need to amend the data on my the wheel weight - the carbon deep sections are a full kilo lighter when built up with the cassette, and the others are disc brake which I believe is another disadvantage aerodynamically or so I’ve read. I’m fairly sure a nice Wheelset & dropping that extra 2 lbs of weight will make all the difference but $$$$$

These group rides typically stay on the limit and I need every reasonable advantage I can get.

[amngwlvs]

I'd imagine the weight difference and depth of the wheels are the bigger cause for a difference in speed than the aerodynamics of the frame and disc brakes.

Now if you were to compare a Giant TCR and Giant Propel (or Emonda and Madone, etc) with the same spec and wheels that would be a much better comparison.

[TonyM]

How do you ride in your club’s ride? I mean how long and often are you in the front? if you are not in the front or not long enough but more in the pack then the aero advantage will mostly disappear...

[AC427]

Typically no-one gets a free ride, although it does happen. Time on the front varies depending on training goal. Sometimes 5 seconds, sometimes can be 5 minutes. Definately pushing more watts on the gravel constantly, although yes, it does diminish in the rotation. Corners are what kicks people out with the surge if your placed wrong, but i seem to be able to close the gap on the madone at those times, whereas it rarely happens on the other. Maybe its partly psycological, but my Quarq doesn't lie and i can not return the same speed for effort exerted. N+1 sounds great, but not financially or logistically feesible so i'm trying to narrow to one great do it all. Club riding one week, Dirty Kanza next. If all of this gain is in the wheelset, i'm already there & the Madone will be sold funding a wheel upgrade. It will be cool to then run some tests after that between road, gravel & 650b wheelsets on the same bike to measure real world gains

[Marin]

There was a nice apples-to-apples comparison in a German mag (not Tour) last month, let me see if I can dig it up tonight. Bottom line was: An aero frame is indeed measurably faster at 0 yaw. I was disappointed

[amngwlvs]

N+1 sounds great, but not financially or logistically feesible so i'm trying to narrow to one great do it all. Club riding one week, Dirty Kanza next. If all of this gain is in the wheelset, i'm already there & the Madone will be sold funding a wheel upgrade. It will be cool to then run some tests after that between road, gravel & 650b wheelsets on the same bike to measure real world gains

Finding a great do it all bike can be a challenge especially if you're looking for both gravel and aero in the same bike. You may need to comporomise on both fronts a bit and meet in the middle. My choice for that was a Giant TCR Disc and so far, so good (though the only gravel I really ride is the odd dirt/gravel road for a couple of km's here and there).

I won't say the gain is all in the wheelset because no doubt the aero frame will make a difference but based on what you've described I would guess that the wheels will make a bigger difference of the two.

[AJS914]

Wheels aside, you are probably getting a handful of free watts from your Madonne since it has aero kamm tail tubes. Is that enough watts to really make a difference? You could also install an integrated aero bar to gain back a few watts but maybe that wouldn't be strong enough for gravel. Not sure.

Other ways to gain a few watts - aero road helmet, form fitting race jersey or skinsuit, narrower bars, more aero position, shave legs/beard, etc.

[mattr]

What AJS says. Until you've optimised all the low hanging fruit, clothes, helmet, shoes, bars, wheels/tyres, position. The frame is just going to be a huge expenditure for relatively little gain.

Unless you've already done that, then get wheels, then frame.

[Jugi]

Terrain is dead flat, group rides are single paceline & sit between 24-35mph constant.

...

Madone has 50mm Aeolus 5 carbon clinchers with 25mm pro-1's tubeless, Gravle bike has Stans No-Tubes Grail and 28mm S-Works tubeless. Much hevier - i'm giving away 500g right off the bat.

The wheels are clearly the big issue, or seems so to me.

Based on my limited experience in racing and fast group riding, I'd say you have nailed it there.

In my opinion, complete wheelset's weight is a critical feature in a fast group. Although it may seem like the group is moving at a steady speed, holding position in the group requires constant adjustment from the individual. If the group is riding nervously (ie. pace is a little bit uncomfortable for most) the constant adjustment is more prevalent. Of course rider skill is involved as well, because seasoned riders are very fluent in working as a part of a group. They avoid spikey power delivery just by anticipating situations better, therefore conserving energy and avoiding going too far to red zone. After all, there is a very small difference between riding hard but controlled or suddenly blowing up.

Look at what the pros ride. Mostly light wheels with 20-40mm rims, and their main concern is good energy economy in a fast paced group. As long as a rider is in the group's "dirty air", I wouldn't sacrifice ride quality by choosing an aero bike. However good, form fitting kit offers "completely free" watts, and an aero helmet helps during your turns in the front.

[bikesrdangerousmmk]

What AJS says. Until you've optimised all the low hanging fruit, clothes, helmet, shoes, bars, wheels/tyres, position. The frame is just going to be a huge expenditure for relatively little gain.

Unless you've already done that, then get wheels, then frame.

Somewhat disagree: much more willing to pay extra for an aero frame and not have to shave legs.