aero frame query for seasoned riders / members in relation to normal rider

Discuss light weight issues concerning road bikes & parts.
diegogarcia
Posts: 494
Joined: Sat Apr 24, 2010 7:31 pm

by diegogarcia

Here is a question in relation to the often discussed aero is faster.

Citing myself as an example, on my Cervelo R5 2018 which Cervelo cite as psuedo aero I suppose, last on Saturday, on rolling roads (1,800 feet) I completed a solo point to point ride of 43.5 miles in 2 hours 18 into a mild headwind with no flapping kit, a Met Manta helmet, no overshoes, 58mm wheels running pro one 25mm, round bars, not aero. The Stravistix app cite my 75% average of 21.9mph which I was pleased with, but entered into a discussion with a couple of riders yesterday as to how much an aero frame might shave time + save time, help a rider along.

Now using a Giant Propel as an example, Giant claim that this bike save you 40 seconds over 40K and aero dividends kick in at 40kph or a tad under 25 mph.

However, looking at the data, I effectively spent just under 5 minutes above this speed, a short period of time above this speed and over 18 minutes of the two hours at 21/22 mph. So to my mind, an aero frame is wasted as my speed is more or less below the mythical 40kph.

But, here is the rub. A fellow rider claims an aero bike will hold speed better thus pushing me further up the chart and effectively save time, or make me 'quicker'. To my mind, the outlay of an aero frame will net me perhaps one or two minutes, which I agree is a lot in terms of cycling, but as a middle aged chap who rides for fun and in no way competes does this render full on aero pointless and in that i am talking Madone, S5, Propel and co. Interestingly over several forums, I have noticed aero engineers, people in the industry be it bikes or planes all cite aero frames as 'faster/more efficient' but forum users say not. Any thoughts on real world performance for the average riders ? Anyone else running two frames and comparing a ride ? What is the deal ? Are aero bikes a triumph of marketing, the work of engineers or just a load of c**p ! Is there a benefit below 25 mph or is the faster you go the faster you get north of 25mph ?

Image

Image

Image
Last edited by diegogarcia on Mon Sep 17, 2018 11:32 am, edited 2 times in total.

by Weenie


GlacialPace
Posts: 51
Joined: Mon Jul 30, 2018 12:37 am

by GlacialPace

Aero is faster, but if you are not racing then the gains are very marginal. I feel like if you are in a bunch and struggling to hold on then an aero frame might save you 5-10W which might just be the difference between hangin on and getting dropped, or it might be the difference between having the legs for a proper sprint effort at the finish and not quite having the same power.
For lone non competative riding aero componentry is not really worth it IMO. Sure, get fitted clothing and ride in the most aero position you are still comfortable in but I think for the type of riding you describe a nice comfortable relativly light bike is the best bet.

diegogarcia
Posts: 494
Joined: Sat Apr 24, 2010 7:31 pm

by diegogarcia

GlacialPace wrote:
Mon Sep 17, 2018 10:53 am
Aero is faster, but if you are not racing then the gains are very marginal. I feel like if you are in a bunch and struggling to hold on then an aero frame might save you 5-10W which might just be the difference between hangin on and getting dropped, or it might be the difference between having the legs for a proper sprint effort at the finish and not quite having the same power.
For lone non competative riding aero componentry is not really worth it IMO. Sure, get fitted clothing and ride in the most aero position you are still comfortable in but I think for the type of riding you describe a nice comfortable relativly light bike is the best bet.
I hear you. Ultimtely the limiting factor is my ability, not the frame I think and in our coffee chat yesteday, I said I felt £2500+ for 120 seconds is not great value :mrgreen:

I also said changing my chainring from 52 to say a 54/55 would achieve more gain on the chain thus more distance per revolution....

moonoi
Posts: 495
Joined: Sat Nov 21, 2015 3:04 pm
Location: Earth

by moonoi

GlacialPace wrote:
Mon Sep 17, 2018 10:53 am
Aero is faster, but if you are not racing then the gains are very marginal. I feel like if you are in a bunch and struggling to hold on then an aero frame might save you 5-10W which might just be the difference between hangin on and getting dropped, or it might be the difference between having the legs for a proper sprint effort at the finish and not quite having the same power.
For lone non competative riding aero componentry is not really worth it IMO. Sure, get fitted clothing and ride in the most aero position you are still comfortable in but I think for the type of riding you describe a nice comfortable relativly light bike is the best bet.
Not sure I agree, I have a Chapter 2 Tere and a Colnago Concept, and riding out solo and in to a headwind I can feel a massive amount of difference in the amount of power needed to maintain the same speed between the two, with the Concept requiring less effort/power for the same speeds.

I would say that if you're riding in a bunch, the aero benefit is negligable, you'd benefit more working on your positioning in the group to save energy/power than riding an aero frame.

User avatar
VTR1000SP2
Posts: 445
Joined: Tue Nov 05, 2013 8:21 pm

by VTR1000SP2

Cervelo takes on this very topic - https://www.cervelo.com/en/engineering- ... ast-riders

They consider the aero advantage of a helmet, wheels, and frame not just the frame.

Sent from my iPhone using Tapatalk
42.

Stueys
Posts: 214
Joined: Sat Nov 22, 2014 1:12 pm

by Stueys

I've always had the same question. My logic has been that aero is important but an aero frame by itself probably isn't going to give me much over my R5 semi-aero frame. That assumes that I've tackled the 'low hanging fruit';
- aero road helmet
- aero position and kit
- aero wheels
- aero bar (so front end is relatively aero)

So an out and out aero frame would probably give me something more but I suspect it's not more than 4-5 watts over my current set up. Having said that my next bike would be a full on aero frame. When I got my R5 I would have made compromises to go full on aero, the bikes coming out now have pretty much had those compromises designed out. But I don't think the gain is sufficient to make me change any earlier.

diegogarcia
Posts: 494
Joined: Sat Apr 24, 2010 7:31 pm

by diegogarcia

Couple of great replies. The Cervelo article is interesting as this sums it up, ultimately, the gains are minimal / marginal but there if required and says it all in so much 1.30 for a fast guy. If racing, massive difference when thinking F1 races are won in tenths and bike races are won by seconds.

As ever, if you like the look of the bike and it compels you to ride it then all power to your elbow.

AJS914
Posts: 2390
Joined: Tue Jan 28, 2014 6:52 pm

by AJS914

To my mind, the outlay of an aero frame will net me perhaps one or two minutes, which I agree is a lot in terms of cycling, but as a middle aged chap who rides for fun and in no way competes does this render full on aero pointless
For your purposes you obviously don't need to buy new equipment just to go faster. Though, at one point you thought you needed 58mm wheels. :-)
Interestingly over several forums, I have noticed aero engineers, people in the industry be it bikes or planes all cite aero frames as 'faster/more efficient' but forum users say not. Any thoughts on real world performance for the average riders ?
Aero works but there are some people on the forum that seem to want to deny or minimize aero gains in every thread. To me it's like climate change deniers. Honestly, I don't know what their vested interest is in putting down aero bikes in every thread.

So yes granted, one doesn't need to buy a new bike for riding out solo or just doing recreational rides with your friends. Your aero frame might save you 1 km/hr. Is that significant to your rides? Most likely not.

RyanH
Moderator
Posts: 2236
Joined: Tue Jan 17, 2012 4:01 pm
Location: Los Angeles, CA
Contact:

by RyanH

I don't know what the new R5 tests at but assuming it's about on par with the new Tarmac, then there's going to be approximately a 0.02 CdA difference due to frames (S5). At 300w, this equates to 40.2kph vs 39.4kph assuming a CdA of approximately 0.3 for a rider on an S5. These are just quick and dirty numbers but I expect it should at least get you in the right direction.

ETA: It's a 0.7kph difference at 200w and 0.9kph at 400w.

diegogarcia
Posts: 494
Joined: Sat Apr 24, 2010 7:31 pm

by diegogarcia

AJS914 wrote:
Tue Sep 18, 2018 2:55 am
To my mind, the outlay of an aero frame will net me perhaps one or two minutes, which I agree is a lot in terms of cycling, but as a middle aged chap who rides for fun and in no way competes does this render full on aero pointless
For your purposes you obviously don't need to buy new equipment just to go faster. Though, at one point you thought you needed 58mm wheels. :-)
Interestingly over several forums, I have noticed aero engineers, people in the industry be it bikes or planes all cite aero frames as 'faster/more efficient' but forum users say not. Any thoughts on real world performance for the average riders ?
Aero works but there are some people on the forum that seem to want to deny or minimize aero gains in every thread. To me it's like climate change deniers. Honestly, I don't know what their vested interest is in putting down aero bikes in every thread.

So yes granted, one doesn't need to buy a new bike for riding out solo or just doing recreational rides with your friends. Your aero frame might save you 1 km/hr. Is that significant to your rides? Most likely not.
Well put. Lack of knowledge or education perhaps ? Seems to me aerospace experts which have been brought into the industry have more knowledge than most. One thing to note however is that of the three wheelsets I run, the 58mm are clearly faster than my 30mm tubeless climbing wheels on the right roads.

diegogarcia
Posts: 494
Joined: Sat Apr 24, 2010 7:31 pm

by diegogarcia

RyanH wrote:
Tue Sep 18, 2018 4:55 am
I don't know what the new R5 tests at but assuming it's about on par with the new Tarmac, then there's going to be approximately a 0.02 CdA difference due to frames (S5). At 300w, this equates to 40.2kph vs 39.4kph assuming a CdA of approximately 0.3 for a rider on an S5. These are just quick and dirty numbers but I expect it should at least get you in the right direction.

ETA: It's a 0.7kph difference at 200w and 0.9kph at 400w.
Thanks great data.

Think I will wait 20 odd years til my 70th year and buy an e-bike :mrgreen: :mrgreen: :mrgreen:

jih
Posts: 168
Joined: Fri Jan 29, 2016 12:54 pm

by jih

When you go on rides, how much time do you spend on the front of the group? If you're not on the front the benefit will be a lot less.

hannawald
Posts: 321
Joined: Sat Dec 17, 2016 7:28 pm

by hannawald

On my beloved route there is a long almost flat slightly downhill section. Sometimes i go 50km/h, sometimes 40km/h. It depends on the wind. I guess there is no way I can recognise 0,5 km/h difference.
In other sections it will be more about my position on the hoods, if i took a drink...
In bunch of others there will be no difference..so the biggest difference is in time trial or being in the front of the group or trying to close a gap in the group..

On the other hand classic frame may keep you fresher so you may be in better condition at the end of your ride..

So hard to say:)

alcatraz
Posts: 1301
Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

An aero frame is a poor place to start collecting aero points.

However, having exhausted all other options it will eventually be the best next upgrade.

It is one of the worst dollar/watt upgrades unfortunately.

AJS914
Posts: 2390
Joined: Tue Jan 28, 2014 6:52 pm

by AJS914

I've been thinking more about aero purchases lately because I started doing fast group rides again.

I raced for 7 years in my twenties but at 52 I'm on the tail end of my group fitness-wise. My FTP is around 220 watts.

When things get heated up the group rolls around 40-50 km/hr. (25-30mph)

When I add up aero gains from various sources it looks like:

50mm wheels 25 watts
frame 20 watts
bars 5 watts
aero helmet 10 watts

(And numbers are much higher at 50 km/hr.)

60 extra watts at my ftp when I'm taking a pull, trying to bridge a gap, or just hanging on for dear life is a substantial boost for someone with my FTP. It makes me consider aero equipment.

Yes, one could make the argument that maybe that is 10 or 20 minutes of a 3 hour group ride. And I'm not ready to drop $8K on a new Venge Pro so this is all theoretical but I might do wheels, aero helmet and aero jersey to start with.

by Weenie


Post Reply
  • Similar Topics
    Replies
    Views
    Last post