Axs and osp: drivetrain inefficiency vs aero

Discuss light weight issues concerning road bikes & parts.
Hexsense
Posts: 1061
Joined: Wed Dec 30, 2015 12:41 am

by Hexsense

RocketRacing wrote:
Sat Oct 19, 2019 2:42 pm
wheelsONfire wrote:
Sat Oct 19, 2019 8:57 am
I should add one thing, if a dude is top trained, i can see the idea of going for aero components, i really can.
But still, it is a Tri bike that would make the change towards higher speed.
Slower riders get more seconds on course saved for going aero. Simply because they are on course longer.
More time saved when counting in time (seconds). Less time saved when comparing in percentage, correct?
The slower you are, the less percentage of slow down force being aero drag. So as percentage, the aero gain (or lose) is less significant ?

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Calnago
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by Calnago

RocketRacing wrote: ...Slower riders get more seconds on course saved for going aero.
Specialized was really reaching deep when they spewed out that nonsense to try to convince people that no matter how slow they go, aero counts. And the slower you are, the more time you save.

Please... at some point you just have to say “Whaaaat...?” Lol

Group waiting for “AeroBob” at end of the ride: “Hey Bob, we were just about to come back looking for you, did you get lost or something?”
AeroBob: “No, I was just going slow to save even more seconds with my new aero bike”.
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by Weenie


RocketRacing
Posts: 947
Joined: Thu May 10, 2018 2:43 am

by RocketRacing

Hexsense wrote:
Sat Oct 19, 2019 8:17 pm
RocketRacing wrote:
Sat Oct 19, 2019 2:42 pm
wheelsONfire wrote:
Sat Oct 19, 2019 8:57 am
I should add one thing, if a dude is top trained, i can see the idea of going for aero components, i really can.
But still, it is a Tri bike that would make the change towards higher speed.
Slower riders get more seconds on course saved for going aero. Simply because they are on course longer.
More time saved when counting in time (seconds). Less time saved when comparing in percentage, correct?
The slower you are, the less percentage of slow down force being aero drag. So as percentage, the aero gain (or lose) is less significant ?
Something like that. It comes down to what the numbers are. You need to calculate it out.

RocketRacing
Posts: 947
Joined: Thu May 10, 2018 2:43 am

by RocketRacing

Calnago wrote:
Sat Oct 19, 2019 8:50 pm
RocketRacing wrote: ...Slower riders get more seconds on course saved for going aero.
Specialized was really reaching deep when they spewed out that nonsense to try to convince people that no matter how slow they go, aero counts. And the slower you are, the more time you save.

Please... at some point you just have to say “Whaaaat...?” Lol

Group waiting for “AeroBob” at end of the ride: “Hey Bob, we were just about to come back looking for you, did you get lost or something?”
AeroBob: “No, I was just going slow to save even more seconds with my new aero bike”.
You are joking right? How do you argue with physics? I did some rough math, so don't be too hard on me.

I am glad you mentioned aerobob. Good guy.

Aerobob and his identical twin brother aerosteve are in a 100km race on idential tt bikes. Aerosteve can crush out 331w on average at 45km/hr. He is a monster. (Some think he is on the juice...)

Aerobob only puts out 250w average. What a loser. Aerosteve crushes his time on course.

So they repeat the same race, but they each have a great new confabulator helmet that magically saves each of them 10w. Aerosteve is now just under 1.5 minutes faster. Aerobob, the slowpoke he is, is now 2.2minutes faster. Aerosteve still wins the race by a landslide, but aerobob had more to gain from that 10w saved because that 10w represented a greater proportion of his total power. His percentage of savings was higher vs his power output.

Now it is not that easy. The confabulator helmet may save 10w at 45km/hr, but if you math it out... it only saves 7.29w at aerobobs speed of 40.5km/hr (speeds are pre-confabulator). That is worth 1.6 minutes for aerobob. Compare that to 10w saving for aerosteve at 1.5minutes saved. Aerobob, as slow as he might be, gained more from that confabulator helmet, even at his slower speed. Even when the aero gains from that helmet were corrected for his lower speed.

So why is this? Well, That is the exponential nature of drag. Air resistance is proportional to velocity squared.

Still don't believe physics? Lets look at aerojeff. His average speed is a pathetic 30km/hr over that 100km race. That 10w confabulator helmet at 45km/hr is only worth 2.96w at 30km/hr!!! How much time does aerojeff save on course with the confabulator?!? 2.05 minutes. Or just over 30s more than "mr 45km/hr" aerosteve saves with the same helmet.

The math gets even more complex as we get towards 15km/hr, as things like crr become a bigger player at those speeds. that is where the rough rule of thumb of "at speeds over 15 km/hr, aero becomes increasingly more important than weight or crr." comes from.

So what i say to people is... if you are slow, dont sweat aero. You will see gains, but you probably dont care anyway. If you want to be fast, aero IS (almost) everything. The faster you go, the more it matters.

Me and a local rider have near identical ftp. But on the climbs i crush him because i am lighter, and on the flats i crush him because i am more aero. And that is with my un aero road bike (aero wheels only, but low position, aero helmet and jersey). On my tri bike on the flats... i am in another stratosphere. When we rode together and i dropped him frequently, he said "i need to get me some of that aero shit".

Jugi
Posts: 612
Joined: Sun Jun 24, 2018 8:10 am

by Jugi

RocketRacing wrote:You are joking right? How do you argue with physics? I did some rough math, so don't be too hard on me.
He is a hilarious internet-phenomenon. Most likely the next argument is "I'm not interested in riding fast because I ride my route at my pace, so the laws of physics can go f**k themselves".

talltales
Posts: 93
Joined: Mon Mar 11, 2019 10:43 pm

by talltales

RocketRacing wrote:
Fri Oct 18, 2019 5:28 pm
ichobi wrote:
Fri Oct 18, 2019 3:10 pm
wheelsONfire wrote:Why don't i believe all these things have a benefit in real world conditions!?
Everybody wants to go faster, isn't it time to see ourselves as the limiting factor?
E-bikes must be the answer if we truly want to notice anything :-)
And why does it have to be a binary choice? You can improve yourself AND your equipment at the same time....

Sent from my Pixel 2 XL using Tapatalk
I am also always looking to make me and my bike faster. Aside from upgrading my legs, the biggest upgrade in speed for me has been buying a tri bike. Different planet for aerodynamics (and speed).
Yes, Exactly. If you really want to go faster get a tri bike, a tri BAR or a recumbent. Spending thousands on the "flawed" design that is a traditional road bike, to gain a second or two, seem silly unless you are racing and subjected to UCI rules or similar restrictions.

talltales
Posts: 93
Joined: Mon Mar 11, 2019 10:43 pm

by talltales

RocketRacing wrote:
Sun Oct 20, 2019 4:40 am
Calnago wrote:
Sat Oct 19, 2019 8:50 pm
RocketRacing wrote: ...Slower riders get more seconds on course saved for going aero.
Specialized was really reaching deep when they spewed out that nonsense to try to convince people that no matter how slow they go, aero counts. And the slower you are, the more time you save.

Please... at some point you just have to say “Whaaaat...?” Lol

Group waiting for “AeroBob” at end of the ride: “Hey Bob, we were just about to come back looking for you, did you get lost or something?”
AeroBob: “No, I was just going slow to save even more seconds with my new aero bike”.
You are joking right? How do you argue with physics? I did some rough math, so don't be too hard on me.

I am glad you mentioned aerobob. Good guy.

Aerobob and his identical twin brother aerosteve are in a 100km race on idential tt bikes. Aerosteve can crush out 331w on average at 45km/hr. He is a monster. (Some think he is on the juice...)

Aerobob only puts out 250w average. What a loser. Aerosteve crushes his time on course.

So they repeat the same race, but they each have a great new confabulator helmet that magically saves each of them 10w. Aerosteve is now just under 1.5 minutes faster. Aerobob, the slowpoke he is, is now 2.2minutes faster. Aerosteve still wins the race by a landslide, but aerobob had more to gain from that 10w saved because that 10w represented a greater proportion of his total power. His percentage of savings was higher vs his power output.

Now it is not that easy. The confabulator helmet may save 10w at 45km/hr, but if you math it out... it only saves 7.29w at aerobobs speed of 40.5km/hr (speeds are pre-confabulator). That is worth 1.6 minutes for aerobob. Compare that to 10w saving for aerosteve at 1.5minutes saved. Aerobob, as slow as he might be, gained more from that confabulator helmet, even at his slower speed. Even when the aero gains from that helmet were corrected for his lower speed.

So why is this? Well, That is the exponential nature of drag. Air resistance is proportional to velocity squared.

Still don't believe physics? Lets look at aerojeff. His average speed is a pathetic 30km/hr over that 100km race. That 10w confabulator helmet at 45km/hr is only worth 2.96w at 30km/hr!!! How much time does aerojeff save on course with the confabulator?!? 2.05 minutes. Or just over 30s more than "mr 45km/hr" aerosteve saves with the same helmet.

The math gets even more complex as we get towards 15km/hr, as things like crr become a bigger player at those speeds. that is where the rough rule of thumb of "at speeds over 15 km/hr, aero becomes increasingly more important than weight or crr." comes from.

So what i say to people is... if you are slow, dont sweat aero. You will see gains, but you probably dont care anyway. If you want to be fast, aero IS (almost) everything. The faster you go, the more it matters.

Me and a local rider have near identical ftp. But on the climbs i crush him because i am lighter, and on the flats i crush him because i am more aero. And that is with my un aero road bike (aero wheels only, but low position, aero helmet and jersey). On my tri bike on the flats... i am in another stratosphere. When we rode together and i dropped him frequently, he said "i need to get me some of that aero shit".
Physics are real, but Bob is still in the bottom end of the field, no matter what he buys. He may advance from 150th to 145th place ... To Bob that might be significant and worth a lot of money, and thats fine. To me it sounds like lack of perspective.

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wheelsONfire
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by wheelsONfire

^
:thumbup:
Bikes:

Ax Lightness Vial EVO Race (2018.12.21)
viewtopic.php?f=10&t=156137
Paduano Racing Fidia (kind of shelved)
Open *UP* (2016.04.14)


Ex bike; Vial EVO D

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kgt
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Location: Athens, Greece

by kgt

Aerobob is really excited. He advanced from 150th to 145th place spending only $850 on his new aero equipment by brand x! Another $300 or so and he may even gain 1 more place. Wow!
Brand x could not be more happy. Their marketing plan goes great.

RocketRacing
Posts: 947
Joined: Thu May 10, 2018 2:43 am

by RocketRacing

kgt wrote:
Sun Oct 20, 2019 2:29 pm
Aerobob is really excited. He advanced from 150th to 145th place spending only $850 on his new aero equipment by brand x! Another $300 or so and he may even gain 1 more place. Wow!
Brand x could not be more happy. Their marketing plan goes great.
Last i checked this was a discusson of physics and certain relaities of aerodynamics, not if investing in a helmet or tt bike was smarter than investing in the stock market. The question is, does a slower rider save more time on course vs a faster rider, when they both gain the same aero upgrade? The answer is yes, because physics.

And i hope people see the irony that we are on a weight weenie forum. How much to we spend on light bikes that have even less performance advantage per dollar than aero?

And dropping your head and shrugging is pretty cheap.

Finally, aerobob is cat 3. He just won his cat 3 tt race by 29.97s, because his competators lightweightjoe and lightweightbill invested in high modulus carbon lightweight hand made italian widgets (with no aero benefits) instead of an aero confabulator helmet.

If YOU want to be faster than you were before, without accounting for training; upgrade aero and you immediatly get more speed per watt you make. That is a given, and physics dictates that, not opinion. How far you go with that, and how much you wish to spend, and if it really matters, or has value, kind of depends on the individual.

jlok
Posts: 1157
Joined: Tue Jun 30, 2015 3:30 am

by jlok

Well said RocketRacing. If aero or related physics sounds like no value, move on and ignore this thread, or prove the physics wrong. Or start another thread talking about value of aero per dollar or race result per value, whatever.
Litespeed T1sl Disc / BMC TM02 < Giant Propel Advanced SL Disc 1 < Propel Adv < TCR Adv SL Disc < KTM Revelator Sky < CAAD 12 Disc < Domane S Disc < Alize < CAAD 10

RocketRacing
Posts: 947
Joined: Thu May 10, 2018 2:43 am

by RocketRacing

talltales wrote:
Sun Oct 20, 2019 9:33 am
Physics are real, but Bob is still in the bottom end of the field, no matter what he buys. He may advance from 150th to 145th place ... To Bob that might be significant and worth a lot of money, and thats fine. To me it sounds like lack of perspective.
It is all about perspective. And priorities. But no one can argue that if one wants to get faster on a bike: 1: train to get stronger 2: aerodynamics help in most situations.

Maybe aerobob is at the top of his age group field at The Kona Ironman world champs. He likely won't be beating Frodo in his lifetime, No matter what gear he buys. But aerobob just got an advantage on his field because everyone else in his age-group said "why bother unless you are the next Ryf or Frodeno or Bernal or etc." In reality, at the highest level, everyone is optomizing aero in tt/tri, and if you don't follow suit, you are putting yourself in a hole.

The priorities of aero in draft legal racing is more debatable. The gains of some aero component like an aero pully wheel might we worth the same time on course as drafting the peleton a few more seconds before making your move.

The hour record is a very facinating example of how small details can have large measurable results on distance travelled.

talltales
Posts: 93
Joined: Mon Mar 11, 2019 10:43 pm

by talltales

RocketRacing wrote:
Sun Oct 20, 2019 3:50 pm
talltales wrote:
Sun Oct 20, 2019 9:33 am
Physics are real, but Bob is still in the bottom end of the field, no matter what he buys. He may advance from 150th to 145th place ... To Bob that might be significant and worth a lot of money, and thats fine. To me it sounds like lack of perspective.
It is all about perspective. And priorities. But no one can argue that if one wants to get faster on a bike: 1: train to get stronger 2: aerodynamics help in most situations.

Maybe aerobob is at the top of his age group field at The Kona Ironman world champs. He likely won't be beating Frodo in his lifetime, No matter what gear he buys. But aerobob just got an advantage on his field because everyone else in his age-group said "why bother unless you are the next Ryf or Frodeno or Bernal or etc." In reality, at the highest level, everyone is optomizing aero in tt/tri, and if you don't follow suit, you are putting yourself in a hole.

The priorities of aero in draft legal racing is more debatable. The gains of some aero component like an aero pully wheel might we worth the same time on course as drafting the peleton a few more seconds before making your move.

The hour record is a very facinating example of how small details can have large measurable results on distance travelled.
You are the one makeing it into a physics debate. Everybody else, as far as I can see, is just making fun of the silly (but true) argument that the slow poke har more seconds to gain.

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kgt
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Location: Athens, Greece

by kgt

RocketRacing wrote:
Sun Oct 20, 2019 3:06 pm
kgt wrote:
Sun Oct 20, 2019 2:29 pm
Aerobob is really excited. He advanced from 150th to 145th place spending only $850 on his new aero equipment by brand x! Another $300 or so and he may even gain 1 more place. Wow!
Brand x could not be more happy. Their marketing plan goes great.
Finally, aerobob is cat 3. He just won his cat 3 tt race by 29.97s, because his competators lightweightjoe and lightweightbill invested in high modulus carbon lightweight hand made italian widgets (with no aero benefits) instead of an aero confabulator helmet.
Unless bylightweightjoe and lightweightbill are Bernal and Thomas.
Oops!
lol

by Weenie


TobinHatesYou
Posts: 4808
Joined: Mon Jul 24, 2017 12:02 pm

by TobinHatesYou

I question the benefit of oversized pulleys...the larger cages have a negative aero impact, the extra link worth of chain = more weight. Adding an aero fairing over them will probably result in trapped dust/dirt, further reducing efficiency. But this is where placebo comes in. If RocketRacing thinks it will make him faster, it probably will. Same goes for Cat 6 Aerobob. If marginal equipment gains allows\ him to keep up with the smashfest group ride rather than getting dropped 10 miles in, then he'll probably get fitter/faster as a result. Good for him. Or if the 80yo founder of the club can only keep up now with his e-bike, that's fine too.

There's clear aero, weight, rolling resistance gains to be made via equipment choice...doesn't matter what your abilities are. What matters is the priority of the upgrade, whether it really is an upgrade and that placebo. Don't buy "aero" oversized pulleys before you buy Empire SLXs or some other aerodynamic shoe or the best fitting skinsuit for your body type.

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