Since when is 156mm (diameter) bicycle tube sized?
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Re: Giant Goes There: Says Their Disc Brakes Are More Aero Than Calipers [Hybridlete]
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Re: Giant Goes There: Says Their Disc Brakes Are More Aero Than Calipers [GreenPlease]
[ In reply to ]
GreenPlease wrote:
Since when is 156mm (diameter) bicycle tube sized?Have you not seen the size of downtubes in the past few years? They are not far off.
Re: Giant Goes There: Says Their Disc Brakes Are More Aero Than Calipers [Hybridlete]
[ In reply to ]
That's 6" dude. Have you ever seen a Speed Concept in person?
The largest of the quasi-Kamm profiles are found on aero road bikes like the S5 or Venge Vias (relevant chord is still ~1.5" max) and those are designed to be used with.... water bottles.
The largest of the quasi-Kamm profiles are found on aero road bikes like the S5 or Venge Vias (relevant chord is still ~1.5" max) and those are designed to be used with.... water bottles.
Re: Giant Goes There: Says Their Disc Brakes Are More Aero Than Calipers [GreenPlease]
[ In reply to ]
He keeps ignoring that you have to put water bottles on bikes.
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Re: Giant Goes There: Says Their Disc Brakes Are More Aero Than Calipers [GreenPlease]
[ In reply to ]
GreenPlease wrote:
That's 6" dude. Have you ever seen a Speed Concept in person? The largest of the quasi-Kamm profiles are found on aero road bikes like the S5 or Venge Vias (relevant chord is still ~1.5" max) and those are designed to be used with.... water bottles.
Why look at it only front the front? Look at the tube shapes from the side profile. A dimpled cylindrical tube has the same size at any yaw. A Kamm or teardrop has increasing chord size as you increase yaw. Hence 6" is not that far off at yaw, especially if you consider the new funny bikes like the Andean, P5X or Specialized Shiv Tri.
Re: Giant Goes There: Says Their Disc Brakes Are More Aero Than Calipers [BryanD]
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BryanD wrote:
He keeps ignoring that you have to put water bottles on bikes.Or do you? Why do we have aero bottles mounted on handle bars and internal bladders then?
Re: Giant Goes There: Says Their Disc Brakes Are More Aero Than Calipers [Hybridlete]
[ In reply to ]
Hybridlete wrote:
GreenPlease wrote:
That's 6" dude. Have you ever seen a Speed Concept in person? The largest of the quasi-Kamm profiles are found on aero road bikes like the S5 or Venge Vias (relevant chord is still ~1.5" max) and those are designed to be used with.... water bottles.
Why look at it only front the front? Look at the tube shapes from the side profile. A dimpled cylindrical tube has the same size at any yaw. A Kamm or teardrop has increasing chord size as you increase yaw. Hence 6" is not that far off at yaw, especially if you consider the new funny bikes like the Andean, P5X or Specialized Shiv Tri.
You're suggesting high AR airfoils whether full or truncated, should be replaced with large diameter dinpled cylinders?
Re: Giant Goes There: Says Their Disc Brakes Are More Aero Than Calipers [Ai_1]
[ In reply to ]
Ai_1 wrote:
What are you talking about? You're suggesting high AR airfoils whether full or truncated, should be replaced with large diameter dinpled cylinders?
Yes, if you want the best average performance over a wide range of yaw.
Re: Giant Goes There: Says Their Disc Brakes Are More Aero Than Calipers [Hybridlete]
[ In reply to ]
I have been drinking, so what the hell...
Exactly how much yaw do I need to optimize around?
I know Cervelo's answer, I know Trek's, what is yours. +/- 5* please.
Exactly how much yaw do I need to optimize around?
I know Cervelo's answer, I know Trek's, what is yours. +/- 5* please.
Re: Giant Goes There: Says Their Disc Brakes Are More Aero Than Calipers [Hybridlete]
[ In reply to ]
Hybridlete wrote:
Ai_1 wrote:
What are you talking about?
You're suggesting high AR airfoils whether full or truncated, should be replaced with large diameter dinpled cylinders?
Yes, if you want the best average performance over a wide range of yaw.
What happens when you tilt those shapes at the angle of a typical downtube?
What about the distribution of yaws likely to be seen? If those are mostly centered around zero yaw and only go out +/-10 deg or so, shouldn't the shape be more optimized for that?
http://bikeblather.blogspot.com/
Re: Giant Goes There: Says Their Disc Brakes Are More Aero Than Calipers [Tom A.]
[ In reply to ]
Tom A. wrote:
Hybridlete wrote:
Ai_1 wrote:
What are you talking about?
You're suggesting high AR airfoils whether full or truncated, should be replaced with large diameter dinpled cylinders?
Yes, if you want the best average performance over a wide range of yaw.
What happens when you tilt those shapes at the angle of a typical downtube?
What about the distribution of yaws likely to be seen? If those are mostly centered around zero yaw and only go out +/-10 deg or so, shouldn't the shape be more optimized for that?
Re: Giant Goes There: Says Their Disc Brakes Are More Aero Than Calipers [Hybridlete]
[ In reply to ]
Hybridlete wrote:
Ai_1 wrote:
What are you talking about?
You're suggesting high AR airfoils whether full or truncated, should be replaced with large diameter dinpled cylinders?
Yes, if you want the best average performance over a wide range of yaw.
So a matter of hours ago you were telling us conventional airfoils are far superior to truncated versions and we're fools if we argue otherwise.
Now you're suddenly deciding that the best solution is in fact enormous cylindrical tubes with dimples. Never mind that the size you're advocating is big enough to foul one's pedal stroke. I realise that's not what you really think. You're just talking nonsense in an attempt to defend criticism of another reference you may not understand (I confess I haven't read it myself yet or checked the Re nos, but that doesn't seem necessary at this point).
It's a classic technique by guys who pretend to know more than they do. Every time they can't defend the position they've taken they just ignore the criticisms and questions and just try to divert the discussion with some new assertion.
Now. Go back and answer the queries I posed earlier.
Re: Giant Goes There: Says Their Disc Brakes Are More Aero Than Calipers [Hybridlete]
[ In reply to ]
Below are some queries I posted yesterday in response to specific claims that you've made.
You have not responded to any of them. Instead you moved on to this dimpled cylinder stuff.
Why should we engage with you on this new topic if you're just going to move onto something new as soon as it starts going wrong for you again?
I thought perhaps you'd just decided to ignore my posts, but as soon as I asked something about your new cylinders topic you responded again. So it's clear you just ignore questions you can't answer or where the answer doesn't suit you. Be a grown up, admit your errors and limitations or defend your position. Please answer some of the queries below.
I'd be more inclined to take it easy on you or give you the benefit of the doubt if it weren't for your constant claims to competence and accusations that the rest of us are fools. If that were the case you'd be able to put me in my place. So do it.
If so, define better.
If you want data, and you want to make this an engineering conversation, then start talking like either an engineer, an aerodynamicist or both. I dare you.
You've ridiculed my use of perfectly reasonable language with the laughable implication that it's not precise enough for you. I'd like to see some semblance of precision from you. You have not covered yourself in glory so far!
2. You do realize that, other than the head tube, most of the bike's surface area is not in a low-turbulence, zero-yaw airstream, right?
1. So show me the data. Everyone here is saying Kamm tails are so great but no one has shown any real data where as I have.
2. If you want to go there, a dimpled cylindrical tube performs better at yaw than a Kamm Tail.
What data have you shown?
No need to repeat yourself, just tell me the post number and I'll take a look. Thanks
You have not responded to any of them. Instead you moved on to this dimpled cylinder stuff.
Why should we engage with you on this new topic if you're just going to move onto something new as soon as it starts going wrong for you again?
I thought perhaps you'd just decided to ignore my posts, but as soon as I asked something about your new cylinders topic you responded again. So it's clear you just ignore questions you can't answer or where the answer doesn't suit you. Be a grown up, admit your errors and limitations or defend your position. Please answer some of the queries below.
I'd be more inclined to take it easy on you or give you the benefit of the doubt if it weren't for your constant claims to competence and accusations that the rest of us are fools. If that were the case you'd be able to put me in my place. So do it.
Ai_1 wrote:
.....I'm not sure what you mean about Cd values "meaning it is valid for other uses, not just aircraft fuselages". Can you explain what you mean?...Ai_1 wrote:
.....But, indulging you for a moment, what data are you looking for? Data that Kamm tails perform better than conventional airfoils? If so, define better.
- Better Cd
- Better L/D
- Better structural characteristics
- Better robustness to variation of impinging airflow with respect to 1 and 2 above
- Any criteria of your choice
If you want data, and you want to make this an engineering conversation, then start talking like either an engineer, an aerodynamicist or both. I dare you.
You've ridiculed my use of perfectly reasonable language with the laughable implication that it's not precise enough for you. I'd like to see some semblance of precision from you. You have not covered yourself in glory so far!
Ai_1 wrote:
Hybridlete wrote:
GreenPlease wrote:
1. You do realize that Kamm profiles have come a long way since the 1940s, right? The big innovations have been in how the trailing edges are radiused. Very subtle changes here have very large effects. 2. You do realize that, other than the head tube, most of the bike's surface area is not in a low-turbulence, zero-yaw airstream, right?
1. So show me the data. Everyone here is saying Kamm tails are so great but no one has shown any real data where as I have.
2. If you want to go there, a dimpled cylindrical tube performs better at yaw than a Kamm Tail.
What data have you shown?
No need to repeat yourself, just tell me the post number and I'll take a look. Thanks
Re: Giant Goes There: Says Their Disc Brakes Are More Aero Than Calipers [Hybridlete]
[ In reply to ]
Oh dear, it appears you decided this discussion didn't suit you anymore. I'm a little disappointed...
Re: Giant Goes There: Says Their Disc Brakes Are More Aero Than Calipers [Ai_1]
[ In reply to ]
That is normally what happens when trolls get backed into a corner. Ignore everything and hide but call us all fools.
Make Inside Out Sports your next online tri shop! http://www.insideoutsports.com/
Make Inside Out Sports your next online tri shop! http://www.insideoutsports.com/
Re: Giant Goes There: Says Their Disc Brakes Are More Aero Than Calipers [BryanD]
[ In reply to ]
You forgot insults, and vague appeals to authority- those are popular too.