Jean-Paul Ballard: "The Aerodynamic Revolution in Cycling" | Talks at Google

Discuss light weight issues concerning road bikes & parts.
Mystikal91
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Joined: Tue May 21, 2019 6:08 pm

by Mystikal91

First post on Weightweenies! I hope to stick around, learn and contribute.

https://youtu.be/lmqdqcOvrlc

by Weenie


RocketRacing
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Joined: Thu May 10, 2018 2:43 am

by RocketRacing

Thanks for sharing. I am watching this now.

The quote that struck me was that when climbing, armatures (not what sure what average power to weight that is) benefit from lighter weight over aero when you exceed a 4.5% gradient. For pros, it goes up to 7.5% gradient before weight trumps aero. Swissside has also quoted 6% preciously, which might be more realistic for your competative amature (the type that would watch such a video).

The devil in the details that i like to add is that the lighter the rider, the more the weight of the bike will have an influence on your power to weight. So at 60kg, a light bike will be of more % benefit to me than my 90kg friend. In other words, i have not done the math, but a lighter bike will perform better than an aero bike at marginally lower gradients for lighter riders vs heavy riders. Same goes for lower powered riders... the benefits of a lighter bike will arrive a bit sooner.

Another good one was that rider is 75% aero drag (i knew that) but that frame/fork was 8%, and wheels 8%. I did not know wheels were worth as much as the frame/fork. My message here is follow the “rule of 105” if you have aero wheels, as you don’t want to compromise that 8%. I will add that the more aero the rider/position, the more the wheels/bike plays in aero.

Also, he talked about front rim stability like it was their idea. Zipp was ontop of that long ago based on discussions from josh Portner.

They also have some pretty high profile clients.

My bike is currently a non-aero frame (felt f series). But i made some decisions with aero in mind. What i wear was first. Capitalizing on the super low front of the f series, combined with my great flexability was second. Then i opted for heavier 56mm deep aero rims. I gained 200g vs my mavic r-sys slr’s... but my new rims, and spokes are no question leagues faster. I also opted for aero bottles that while heavier... completly hide in the frame shadow, and likely improve aero bs no bottles. Finally, small details like unwrapped bar tops, clean cable routing, low hoods, tri rig aero skewers, and even taping over frame and crank holes.

And then i made everything else as light as i could within budget. So i kind of ended up with a bike that is in line with modern “lightweight aero bikes”, or “aero climbing bikes”.
Last edited by RocketRacing on Thu Jul 11, 2019 5:27 am, edited 3 times in total.

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TonyM
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by TonyM

That could explain why Ineos is using Lightweight wheels for the stage tomorrow at La Planche des Belles Filles...

RocketRacing
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by RocketRacing

TonyM wrote:
Thu Jul 11, 2019 4:16 am
That could explain why Ineos is using Lightweight wheels for the stage tomorrow at La Planche des Belles Filles...
Sort of. The uci limit throws a wrench in that. Either they are using the wheels to hit the limit, or they are at the limit, and are trading spinning weight for static weight.

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pdlpsher1
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by pdlpsher1

Thanks for sharing. It’s a very good presentation. And also good insights given during the Q&A.

One thing he mentioned in the Q&A is that really wide wheels are horrible aerodynamically at low yaw angles. This is the same finding by Hambini. If you think about it it’s quite a simple logic. Wider wheels have a greater frontal area. So no one should be surprised by this. I’m currently riding 17C wheels. I don’t think any wider will give me any additional benefits. Plus wider wheels are heavier.

Love his response when asked about the Zipp dimples and whale humps.


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AJS914
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by AJS914

I think you have to look at tire wide, 105% rule, and all that. If you are staying with a 23mm tire that stretches to 24-26mm then what is the fastest wheel:

23mm wide
25mm wide u shape
28mm wide (25mm wide at the brake track and 28mm at the widest point creating more of an airfoil)

I'm also surprised we haven't seen pointier tires marketed. The GP4000 was supposedly very aero because it was tall and pointy.

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LAN
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by LAN

I feel like this talk does not relate to road racing. Triathletes and solo amateur riders only.

If the model assume solo rider in the wind at constant power output with no accelerations sure aero wins, but what if you assume a rider tucked in a peloton, with several "micro accelerations", then weight and rolling resistance/bearing friction play a much bigger part. Almost all top riders choose a lightweight or allround bike, and don´t claim that they are all stupid and follow tradition.

He also claimed that singel ring setup was really great, and could save up to 3w. Not so great that you will loose 2-8w because of cross-chaining.

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kgt
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by kgt

+100

K4m1k4z3
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by K4m1k4z3

RocketRacing wrote:
Thu Jul 11, 2019 2:32 am
...and even taping over frame and crank holes.
Glad I'm not the only one. :beerchug:
Giant TCR Advanced Pro 1 Disc '18

TobinHatesYou
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by TobinHatesYou

LAN wrote:
Thu Jul 11, 2019 8:16 pm
I feel like this talk does not relate to road racing. Triathletes and solo amateur riders only.

If the model assume solo rider in the wind at constant power output with no accelerations sure aero wins, but what if you assume a rider tucked in a peloton, with several "micro accelerations", then weight and rolling resistance/bearing friction play a much bigger part. Almost all top riders choose a lightweight or allround bike, and don´t claim that they are all stupid and follow tradition.

He also claimed that singel ring setup was really great, and could save up to 3w. Not so great that you will loose 2-8w because of cross-chaining.

It depends if you are constrained by fatigue or limited by optimum power-to-weight. Most pros are not kJ constrained in long, flat races, but amateurs just upgrading to another category might be. In a crit, it might be that your accelerations out of corners end up being anaerobic instead of neuro efforts, preserving your power reserves for the final sprint or final couple of laps.

In a way aero is more important for amateurs than it is for pros because our races are shorter and we spend more time in our tougher power zones (relatively speaking.)

So yeah if you think the selection or key moment in s race will be made on a >6% climb, bring the light bike. If your race is rolling or flat or the climb comes first followed by a lot of flat ground, consider the aero bike.

And no, bearing friction differences are tiny in the scope of racing...the difference between a complete load out of the best ceramics and typical steel bearings is probably around 3 watts in that ~250W range. Aerodynamic drag is significantly more important...this is basic stuff.

TL;DR It’s insane to me that someone would try to emphasize bearing friction over aero in any realistic scenario.

AJS914
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by AJS914

TobinHatesYou wrote:
Thu Jul 11, 2019 9:34 pm

It depends if you are constrained by fatigue or limited by optimum power-to-weight. Most pros are not kJ constrained in long, flat races, but amateurs just upgrading to another category might be. In a crit, it might be that your accelerations out of corners end up being anaerobic instead of neuro efforts, preserving your power reserves for the final sprint or final couple of laps.

In a way aero is more important for amateurs than it is for pros because our races are shorter and we spend more time in our tougher power zones (relatively speaking.)

Pros vs. Amateurs is an interesting concept. If I did aero everything. Bike, deep wheels, tight fitting kit, shoe covers, helmet, etc. I can get up to maybe 70+ watts saved at race speeds. For me, that is a huge percentage of my FTP. For a Pro with a 400+ watt FTP the percentage is much less.

spdntrxi
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by spdntrxi

^ unless you are riding a bike shaped like a mack truck and dressed like the batman with a cape.. it's never going to add to 70w+

TobinHatesYou
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by TobinHatesYou

Shoe covers is a topic in itself. Some shoes like Giro Empire SLX are more aero without Velotoze.

AJS914
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by AJS914

spdntrxi wrote:
Fri Jul 12, 2019 1:08 am
^ unless you are riding a bike shaped like a mack truck and dressed like the batman with a cape.. it's never going to add to 70w+
From the various charts, white papers, and blog posts that I've read the total watts saved can be significant. Hambini's chart alone claims 40 watts between non aero Ksyriums and a 50mm set of wheels. Anway, I don't want to debate actual numbers as the point is the same. Whatever the number is, it's a much larger percentage of theshold for amateurs than it is for pros.

by Weenie


TheRich
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by TheRich

AJS914 wrote:
Fri Jul 12, 2019 1:03 am
Pros vs. Amateurs is an interesting concept. If I did aero everything. Bike, deep wheels, tight fitting kit, shoe covers, helmet, etc. I can get up to maybe 70+ watts saved at race speeds. For me, that is a huge percentage of my FTP. For a Pro with a 400+ watt FTP the percentage is much less.
They're going faster and fighting more drag, I bet the percentages are similar.

They talked about it in one of the Specialized win-tunnel videos...the time saved in a 40k tt for whatever change was pretty similar despite different average speeds.

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