Weight Vs Aerodynamics -Wheelset Selection

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Re: Weight Vs Aerodynamics -Wheelset Selection

Postby jcjordan » Fri Feb 08, 2013 8:28 pm

toolonglegs wrote:So with all of us using deepish wheels.... who has an Giro Air Attack helmet?... 3 or 4 meters difference in a 30 sec sprint :P .

I have the cover for my lazer helium and have used it in a race
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Re: Weight Vs Aerodynamics -Wheelset Selection

Postby mikesbytes » Sat Feb 09, 2013 3:42 am

jcjordan wrote:
toolonglegs wrote:So with all of us using deepish wheels.... who has an Giro Air Attack helmet?... 3 or 4 meters difference in a 30 sec sprint :P .

I have the cover for my lazer helium and have used it in a race


Can't see any mention of the aussie sticker on the Giro web site, not that affects you http://www.giro.com/as_en/products/men/helmets/air-attack-shield-16170.html (note I pointed to as_en)

Where do you get the helmet covers?
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Re: Weight Vs Aerodynamics -Wheelset Selection

Postby Alex Simmons/RST » Sat Feb 09, 2013 6:49 pm

Speaking of aero wheels (and other aero goodness), I'm just back from the Dunc Gray Velodrome, having coached rider Jayson Austin to a new world masters hour record for M40-44.

48.411km

which adds 1.284km to the previous record of 47.127km set by Dave Stevens in December 2011.
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Re: Weight Vs Aerodynamics -Wheelset Selection

Postby toolonglegs » Sat Feb 09, 2013 6:53 pm

I think the helmet covers are actually illegal to race with as it is a "bolt on" aero aid... someone could protest you if they want to, not that it is likely to happen.
Mike the Giro aero helmet will have an Aus sticker soon enough I am sure. The aero advantages are pretty good with them so expect to see them more often... I need a new helmet so must admit I am tempted even with the tool factor :P .


Alex Simmons/RST wrote:Speaking of aero wheels (and other aero goodness), I'm just back from the Dunc Gray Velodrome, having coached rider Jayson Austin to a new world masters hour record for M40-44.
48.411km
which adds 1.284km to the previous record of 47.127km set by Dave Stevens in December 2011.


Good stuff Alex!... was Jayson's previous record in the 35-40 age group?. Also is that on the "Standard Merckx" set up or are you allowed to actually get aero?.
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Re: Weight Vs Aerodynamics -Wheelset Selection

Postby Alex Simmons/RST » Sat Feb 09, 2013 7:57 pm

toolonglegs wrote:Good stuff Alex!... was Jayson's previous record in the 35-40 age group?. Also is that on the "Standard Merckx" set up or are you allowed to actually get aero?.

Yes, Jays still holds the 35-39 record (48.315km) which was set nearly 4 years ago same venue.

The records for Masters best hour are set using pursuit bike equipment regulations.

This was the second faster hour ever ridden in Australia, behind Brad McGee's all comers Australian record of 50.052km set in 1997 aged 21 (and with more aero bike position options permitted back then).
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Re: Weight Vs Aerodynamics -Wheelset Selection

Postby Xplora » Sat Feb 09, 2013 9:00 pm

^^^ He got FASTER as he got older?! :shock: :shock: :shock:
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Re: Weight Vs Aerodynamics -Wheelset Selection

Postby skull » Sat Feb 09, 2013 9:02 pm

Have you managed to get this record approved by winston yet? Till then it is all graphs and numbers. :D


Well done to rider and coach.
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Re: Weight Vs Aerodynamics -Wheelset Selection

Postby nickl » Sat Feb 09, 2013 10:02 pm

Alex Simmons/RST wrote:
__PG__ wrote:
Alex Simmons/RST wrote:http://alex-cycle.blogspot.com.au/2013/02/the-sum-of-parts.html

I'm crunching some numbers to see what sort of theoretical improvements I can get out of a carbon tubular wheelset for a hillclimb. How easy is it to track down real Cd/intertia numbers for Zipp/Enve rims?

Cd is tricky, as it depends on a few things, and typically varies with yaw and where on a bike it's used (obviously a rear wheel is dealing with some different air flow issues than the front wheel). Been a while since I've seen an updated table of wheel aero comparisons. There was one done about 5 years ago by http://www.rouesartisanales.com/ and they also measured moment of inertia for many wheels available at the time, but IIRC they don't provide values for Cd or I, but rather estimated power demand differences (unfortunately - although one can determine an equivalent change in Cd).

As for moment of inertia, well it's possible to set up a rig designed to measure it (or a very good approximation) - basically a big pendulum with the wheel in a vertical plane as the mass at end of a long string, but need to be able to control the plane of the wheel to be the same as the plane of the pendulum swing, or another method is hanging a wheel in horizontal plane from a rod through the axle and set up like a torsional spring. Measuring the period of either can provide enough information to calculate moment of inertia.

Velonews have a rig, and they might provide such details when doing a wheel review, can't say I've looked beyond one table Zinn published, which shows the spread of "I" amongst various wheels is pretty small, for a kinetic energy factor that's pretty small to start with. He did have values for a Zipp 202.

But you can assume that most 700c wheels will be somewhere between 0.1225 kg.m^2 and 0.06125 kg.m^2, per kg of rim mass, with the former being with all rim mass at the outer edge and the latter a rim that extends all the way to the centre (i.e. a disk). Then add the moment of inertia for the hub, which will be an even smaller factor, by another couple of orders of magnitude.


Tour Magazine measured both moment of inertia and aerodynamic resistance (in watts used) at various speeds. See pg 98 of http://www.tour-qtr.com/epaper_4_2011 for aero wheels and pg 86 for non-aero wheels.

It's an excellent test btw.
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Re: Weight Vs Aerodynamics -Wheelset Selection

Postby Alex Simmons/RST » Sun Feb 10, 2013 6:12 am

nickl wrote:Tour Magazine measured both moment of inertia and aerodynamic resistance (in watts used) at various speeds. See pg 98 of http://www.tour-qtr.com/epaper_4_2011 for aero wheels and pg 86 for non-aero wheels.

It's an excellent test btw.

Nice. One can see how things are so similar at low yaw but vary considerably at higher yaw angles.

By the way, depending on how people quote the differences you can use the following rule of thumb to quickly ascertain the impact to flat land speed:

5W ~= 0.005m^2 CdA ~= 50g or 5N of drag ~= 0.0005 Crr ~= 0.5 sec/km
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Re: Weight Vs Aerodynamics -Wheelset Selection

Postby Mulger bill » Sun Feb 10, 2013 8:21 am

skull wrote:Have you managed to get this record approved by winston yet? Till then it is all graphs and numbers. :D


Well done to rider and coach.


*splutter* One tea splattered monitor later... :lol:

Big 'grats to Jayson and yourself Alex, that's an awesome number.

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Re: Weight Vs Aerodynamics -Wheelset Selection

Postby mikesbytes » Sun Feb 10, 2013 10:45 am

toolonglegs wrote:I think the helmet covers are actually illegal to race with as it is a "bolt on" aero aid..
I think there were some used in the tour down under. Suppose whether its considered an aero aid or something to keep your head warm.

Alex, congratulations on the 1 hour record. Amazing time !!!!!

I think there may be a one hour record somewhere, perhaps Europe where the "Eddie Merxx" rule applies, which I understand is pretty much a conventional round tube track bike with a maximum of 20mm dish wheels
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Re: Weight Vs Aerodynamics -Wheelset Selection

Postby Alex Simmons/RST » Sun Feb 10, 2013 1:33 pm

mikesbytes wrote:
toolonglegs wrote:I think the helmet covers are actually illegal to race with as it is a "bolt on" aero aid..
I think there were some used in the tour down under. Suppose whether its considered an aero aid or something to keep your head warm.

The chrome-like lazer helmets used at the TDU are complete one-piece, constructed that way and not attachments. Helmets covers or attachments like that used by Cavendish in Worlds 2011 road race are not permitted under UCI rules.

mikesbytes wrote:Alex, congratulations on the 1 hour record. Amazing time !!!!!

Thanks Mike, but it was an hour long, like all hour records ;-)
just joshing. :D
Suggest people try to ride at 48.4km/h on flat road windless day and see how long they last.

mikesbytes wrote:I think there may be a one hour record somewhere, perhaps Europe where the "Eddie Merxx" rule applies, which I understand is pretty much a conventional round tube track bike with a maximum of 20mm dish wheels

There are two forms of the record for open competition - the athlete's hour and best hour performance. One uses the Merckx style* set up (the equipment rules are defined for that in the UCI rule book and yes round tubes and low profile standard spoked wheels, standard mass start handlebars etc) and the other uses the equipment rules as applied to individual pursuit. Other than that, the way the event is run is the same. It's quite a logistical feat as much as a physical one as you have to apply months in advance to UCI and set a date and time, and of course comply with all anti-doping controls that may be imposed before and at the event (you have to fund the testing as well of course as the venue, timing system and officials costs - it requires an international level UCI commissaire to oversee, plus 6-8 other accredited officials). It ain't cheap to do!


* The irony of the "Merckx rules" as stipulated by the UCI is that the bike Merckx used for his hour record would not actually comply under the current rules.
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Re: Weight Vs Aerodynamics -Wheelset Selection

Postby Nikolai » Sun Feb 10, 2013 1:58 pm

Alex Simmons/RST wrote:* The irony of the "Merckx rules" as stipulated by the UCI is that the bike Merckx used for his hour record would not actually comply under the current rules.


Interesting. Can you please explain more?
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Re: Weight Vs Aerodynamics -Wheelset Selection

Postby zero » Sun Feb 10, 2013 2:20 pm

Nikolai wrote:
Alex Simmons/RST wrote:* The irony of the "Merckx rules" as stipulated by the UCI is that the bike Merckx used for his hour record would not actually comply under the current rules.


Interesting. Can you please explain more?


Its underweight by a full kg.
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Re: Weight Vs Aerodynamics -Wheelset Selection

Postby winstonw » Sun Feb 10, 2013 4:29 pm

zero wrote:
Nikolai wrote:
Alex Simmons/RST wrote:* The irony of the "Merckx rules" as stipulated by the UCI is that the bike Merckx used for his hour record would not actually comply under the current rules.


Interesting. Can you please explain more?


Its underweight by a full kg.


...but as Alex has invested significant time in, weight is overrated.
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Re: Weight Vs Aerodynamics -Wheelset Selection

Postby winstonw » Sun Feb 10, 2013 4:33 pm

Alex Simmons/RST wrote:
toolonglegs wrote:Good stuff Alex!... was Jayson's previous record in the 35-40 age group?. Also is that on the "Standard Merckx" set up or are you allowed to actually get aero?.

Yes, Jays still holds the 35-39 record (48.315km) which was set nearly 4 years ago same venue.

The records for Masters best hour are set using pursuit bike equipment regulations.

This was the second faster hour ever ridden in Australia, behind Brad McGee's all comers Australian record of 50.052km set in 1997 aged 21 (and with more aero bike position options permitted back then).


WRT to aero-coach.com Alex, how do you split the gain in a Masters athlete's performance between improvement in physiology, aerodynamics, bike skill, training, lifestyle outside training, environment?
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Re: Weight Vs Aerodynamics -Wheelset Selection

Postby winstonw » Sun Feb 10, 2013 4:56 pm

Alex Simmons/RST wrote:I have no interest in getting into the wheel manufacturing business, and why on earth would I suggest any wheel manufacturer rely on a couple of charts pertaining to a particular scenario? Please do your yourself a favour and learn about logical fallacies because you introduce them at every turn.


what Alex!!!???? you base your absolutist weight vs aero statements on "a couple of charts pertaining to a particular scenario"....
I look forward to your charts evolving to accommodate real world scenarios integrating variable yaw and velocity, as do Enve's.

If your best defense of your stance is that all wheel manufacturers' R&D is smoke and mirrors marketing hype, then put the challenge out to all of their guys that your grasp on aero vs weight is better informed.

If you want to use examples of Masters athletes you have guided to better performance, as testimony of your superior understanding, put it up against the performance of athletes sponsored by major wheel manufacturers....and objectively quantify the broad baseline of your 'selective' talent testimony.
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Re: Weight Vs Aerodynamics -Wheelset Selection

Postby twizzle » Sun Feb 10, 2013 5:11 pm

:roll:

Go. Away.


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Re: Weight Vs Aerodynamics -Wheelset Selection

Postby jcjordan » Sun Feb 10, 2013 5:29 pm

mikesbytes wrote:
jcjordan wrote:
toolonglegs wrote:So with all of us using deepish wheels.... who has an Giro Air Attack helmet?... 3 or 4 meters difference in a 30 sec sprint :P .

I have the cover for my lazer helium and have used it in a race


Can't see any mention of the aussie sticker on the Giro web site, not that affects you http://www.giro.com/as_en/products/men/helmets/air-attack-shield-16170.html (note I pointed to as_en)

Where do you get the helmet covers?

Got it when I bought the helmet from my LBS
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Re: Weight Vs Aerodynamics -Wheelset Selection

Postby jcjordan » Sun Feb 10, 2013 5:32 pm

toolonglegs wrote:I think the helmet covers are actually illegal to race with as it is a "bolt on" aero aid... someone could protest you if they want to, not that it is likely to happen.

We are not a CAN club but under the AVCC so it's not against the rules
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Re: Weight Vs Aerodynamics -Wheelset Selection

Postby warthog1 » Sun Feb 10, 2013 5:38 pm

twizzle wrote::roll:

Go. Away.


...


And stay away.
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Re: Weight Vs Aerodynamics -Wheelset Selection

Postby toolonglegs » Sun Feb 10, 2013 5:54 pm

zero wrote:
Nikolai wrote:
Alex Simmons/RST wrote:* The irony of the "Merckx rules" as stipulated by the UCI is that the bike Merckx used for his hour record would not actually comply under the current rules.


Interesting. Can you please explain more?


Its underweight by a full kg.


I also understand that the skull cap that Eddy rode with gave him an advantage over a normal helmet you would now have to try the record wearing.
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Re: Weight Vs Aerodynamics -Wheelset Selection

Postby Mulger bill » Sun Feb 10, 2013 6:09 pm

warthog1 wrote:
twizzle wrote: :roll:

Go. Away.


...


And stay away.


Motion seconded, can we have a show of hands?
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Re: Weight Vs Aerodynamics -Wheelset Selection

Postby skull » Sun Feb 10, 2013 6:11 pm

I
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Re: Weight Vs Aerodynamics -Wheelset Selection

Postby Alex Simmons/RST » Sun Feb 10, 2013 6:27 pm

winstonw wrote:
Alex Simmons/RST wrote:I have no interest in getting into the wheel manufacturing business, and why on earth would I suggest any wheel manufacturer rely on a couple of charts pertaining to a particular scenario? Please do your yourself a favour and learn about logical fallacies because you introduce them at every turn.


what Alex!!!???? you base your absolutist weight vs aero statements on "a couple of charts pertaining to a particular scenario"....
I look forward to your charts evolving to accommodate real world scenarios integrating variable yaw and velocity, as do Enve's.

If your best defense of your stance is that all wheel manufacturers' R&D is smoke and mirrors marketing hype, then put the challenge out to all of their guys that your grasp on aero vs weight is better informed.

If you want to use examples of Masters athletes you have guided to better performance, as testimony of your superior understanding, put it up against the performance of athletes sponsored by major wheel manufacturers....and objectively quantify the broad baseline of your 'selective' talent testimony.

Yawn, more strawmen. At least 5 of them in one post. Outstanding effort.
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