Velo News tests 4 aero bikes- Anyone get this yet?

Discuss light weight issues concerning road bikes & parts.
User avatar
djconnel
Posts: 7926
Joined: Wed Sep 26, 2007 1:57 pm
Location: San Francisco, CA
Contact:

by djconnel

I agree: for crits and the end of road races it is typical to carry only a single bottle. That's the best way to go.

But including the rider is obviously preferable: the rider substantially changes the wind flow around the seat post and the rear end.

Still, the data in the VeloNews article will be far from useless. Given two frames, one better without a bottle, it will probably (not certainly) be better with the bottle.

by Weenie


VNTech
Posts: 195
Joined: Tue Jan 25, 2011 8:08 pm

by VNTech

Fear not weightweenies, we've discussed all of this internally and have covered as many bases as possible. We of course have a number of constraints to take into account as well.

I pose this question re: water bottles: what if Bike A's shape is faster with Bottle and Cage A than Bike B, and Bike B is faster with Bottle and Cage B, but you in fact ride and race with Water Bottle C?

Placement, size, cage type, bottle type, etc all would have effect. Since it is a non-standard piece of equipment we left it off, despite the fact that almost everyone rides with a bottle.
VeloNews Magazine/VeloNews.com tech

RussellS
Posts: 701
Joined: Wed Feb 03, 2010 1:31 am

by RussellS

ras11 wrote:If the majorty of folks use 1 water bottle, then test it that way (I doubt this is statiscially true, and that must use two). My point was that no bottles = track bike.


Personally I usually use 1 or 0 bottles. Any ride up to 30 miles will be 0 bottles. Why can't you do without water for 2 hours? Anything above that and I will carry 1 bottle. Probably will not drink from it during the ride due to a couple refreshment stops. During any criterium, 30-45-60 minutes, I would never ever carry a bottle. During a road race, 30-50 miles, one bottle is sufficient.

This is weight weenies? People build up these light weight high dollar bikes? And then strap 4 pounds of water to it? Do you also strap a huge Carradice bag to the saddle and load it up with 5 pounds of tools and gear?

User avatar
Mario Jr.
Posts: 2183
Joined: Sat Jun 12, 2004 8:49 am
Location: Denmark
Contact:

by Mario Jr.

That reply is ridiculous... Please get a wider perspective on what people are using their bikes for. My races are typically around 100-110 kms. I (and all my rivals) are riding two 500 or 750cc bottles, depending on weather. That you only ride crits and stop constantly for refreshments does not reflect many racers behavior, I'm sure.

I look forward to seeing a test WITH a rider, WITH cables and WITH bottles, as this would reflect the real life conditions. Anything else is IMO not more than a qualified guess.

I also look forward to seeing the stiffness test of the all out "Aero" bikes. The latest results I saw in "Roadbike" seemed to confirm that very narrow bikes are also very flexible and suffer from bad handling.

User avatar
djconnel
Posts: 7926
Joined: Wed Sep 26, 2007 1:57 pm
Location: San Francisco, CA
Contact:

by djconnel

I agree it seems less likely which bottle & cage (assuming a standard-size bottle and a typical carbon cage) should make less difference to the ranking of results than whether there is a bottle or cage. For example the Litespeed was specifically designed to be efficient with a bottle.

Image

User avatar
djconnel
Posts: 7926
Joined: Wed Sep 26, 2007 1:57 pm
Location: San Francisco, CA
Contact:

by djconnel

The low-yaw CdA, bike no rider, Zipp 404 wheels... I assume air density = 1.185 kg/m² at the North Carolina wind tunnel.


"standard bike" (unspecified): 0.106
Felt AR: 0.092
Ridley Noah: 0.087
Blue: 0.085
Cervelo S3: 0.083

The contrast with the Tour results really couldn't be more striking. There, the Cervelo was actually slower than the Cannondale System 6 at zero yaw.

Tour reported a typical CdA for zero yaw with rider is 0.31. So a difference of 0.023 (the Cervelo to the "standard bike") is around 7.4% of total wind power. At 40 kph the power difference is 18.6 watts out of 250 watts. At this speed, 33 watts is a typical rolling resistance power (12% of total). Thus, a 7.4% reduction in wind resistance power is around a 2.3% savings in total speed: 85 seconds / hour.

VeloNews claimed more than that: 128 seconds. But they average over yaw angles from -20 to +20 degrees.

I think omitting the rider should overestimate the aero benefit somewhat, so I'd view the VeloNews results as an upper bound on possible savings.

superbikemike
Posts: 35
Joined: Tue Sep 21, 2010 1:33 am
Location: Michigan,USA

by superbikemike

I recived my Velo News in the mail yesterday. Went to this test right away. I ride a Cervelo SLC so I have some intrest in these test results. I was happy to see the Cervelo S3 won the test. Although I would like to know the stiffness numbers on the non areo test bike. Does anyone know those numbers, or at least were I can look at other bikes that have been tested for stiffness ?

Mike
Thanks

Mike

Current Rides
2015 Specialized S-Works Venge DI2
2013 Trek Madone P1 7
2009 Cervelo P3
2008 Cervelo S

User avatar
prendrefeu
Posts: 8609
Joined: Wed Oct 31, 2007 10:32 pm
Location: Los Feliz, Los Angeles, California
Contact:

by prendrefeu

Good to see that the Blue is just barely "slower" (??) than the Cervelo.

In other words: save yo'money! :mrgreen:
Exp001 || Other projects in the works.

User avatar
djconnel
Posts: 7926
Joined: Wed Sep 26, 2007 1:57 pm
Location: San Francisco, CA
Contact:

by djconnel

The Cervelo rated higher in ride quality, however.

User avatar
prendrefeu
Posts: 8609
Joined: Wed Oct 31, 2007 10:32 pm
Location: Los Feliz, Los Angeles, California
Contact:

by prendrefeu

Unless the test physically measured frame deflection using a standardized testing mechanism and then equated that to an interpretation of human reaction to those qualities, ride quality is always subjective.

to re-quote:
prendrefeu wrote:Anyway, country of origin (or country of brand at least) does not determine a frame's qualities. Never has, never will. Nor does country of origin (manufacturing). It is the design, the layup, the rider's karma, the rider's weight, and perceived sensitivities that determine a frame's qualities. Period.


We may also want to add in the factor of 'perceived value' - wherein a rider having knowledge of the frame's monetary value or 'exclusivity' (marketed or otherwise) will rate that frame higher than a frame of less monetary value or exclusivity. There are countless examples of this in any field of interest, not just bicycles, so giving examples at this point is moot.

Any publication which thrives off of the industry's growth, advertising, and appraisal is not immune to the effects of bias through perceived value.
Exp001 || Other projects in the works.

VNTech
Posts: 195
Joined: Tue Jan 25, 2011 8:08 pm

by VNTech

superbikemike wrote:I recived my Velo News in the mail yesterday. Went to this test right away. I ride a Cervelo SLC so I have some intrest in these test results. I was happy to see the Cervelo S3 won the test. Although I would like to know the stiffness numbers on the non areo test bike. Does anyone know those numbers, or at least were I can look at other bikes that have been tested for stiffness ?

Mike


Mike,
The torsional stiffness test will be a constant throughout all our tests this year (six rounds of four bikes total) so you will have plenty to compare to soon enough.


prendrefeu - As noted in the "results" section at the end of the review, we found a distinct correlation between perceived stiffness, as rated prior to the lab testing, and the lab test results. We could feel it distinctly. Those did not correlate to ride quality, though. In other words, "ride quality" does not equal torsional stiffness.

We balanced the subjective ride quality scores and scientific scores for a reason. You need both. No lab can replicate the real world perfectly, and we can't possibly speak for every cyclist regarding the definition of good ride quality. We just know what we like.

Cheers
VeloNews Magazine/VeloNews.com tech

User avatar
prendrefeu
Posts: 8609
Joined: Wed Oct 31, 2007 10:32 pm
Location: Los Feliz, Los Angeles, California
Contact:

by prendrefeu

Damn I love this forum. Thanks for being a part of it, VNTech.
Exp001 || Other projects in the works.

VNTech
Posts: 195
Joined: Tue Jan 25, 2011 8:08 pm

by VNTech

My pleasure, I've been a lurker on this forum for the better part of a decade. Always loved it.

I'm just sorry I couldn't think of a more creative handle. I feel I've ripped off Pez a bit :oops:
VeloNews Magazine/VeloNews.com tech

superbikemike
Posts: 35
Joined: Tue Sep 21, 2010 1:33 am
Location: Michigan,USA

by superbikemike

Thanks VNtech for your great review. Regarding the stiffness tests I have heard over and over again that my Cervelo is not stiff enough in the head tube area. I don't seem to notice it although many people on this forum do. Love to see the numbers between the S3 and some non aero frames. I am looking forward to upcoming tests !

Mike
Thanks

Mike

Current Rides
2015 Specialized S-Works Venge DI2
2013 Trek Madone P1 7
2009 Cervelo P3
2008 Cervelo S

Johnnysmooth
Posts: 183
Joined: Sun Apr 15, 2007 4:56 pm
Location: Beantown

by Johnnysmooth

VNtech,
I rec'd my issue in the mail and also went straight to the tests.

As I was at least trained as an engineer (structural) and do know all the nuances that could go into such a test, believe you and your team have done a good and fair job on the testing. I particularly like the qualitative testing. Sure, we all have our own opinions on how a bike "feels" but combining opinions of a couple of different riders along with the quant testing is great.

Keep up the good work and look forward to the next series of tests.
It only hurts if you think.

by Weenie


Post Reply
  • Similar Topics
    Replies
    Views
    Last post