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Speedplay claims huge wind drag reduction... 33 seconds per hour over "leading brands"

 

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stitchboy

Aug 4, 09 21:31

Post #1 of 63 (9620 views)
Speedplay claims huge wind drag reduction... 33 seconds per hour over "leading brands" Quote | Reply

Speedplay has done just completed wind-tunnel testing of clipless pedals. It looks like they used a pretty repeatable protocal. They claim and look like they beat out Look and Shimano pedals. Something to bear in mind is that the 3 hole mounted Speedplay pedals performed marginally better than the other 2 pedals, .242 to .243. However the big time savings came from Speedplay pedals mounted on 4 hole shoes, with drag at .237. My problem with this data is the 4 hole shoes. Does any manufacturer even make 4 bolt shoes? Every shoe I have seen for the last couple years have been 3 hole. Still a very interesting test and I am always glad to see companies put out aero data, flawed or not. Then we can at least discuss it on this forum and get some much smarter people than me to dissect this data and make sense of it all.

http://www.speedplay.com/...=home.slipperypedals

As an aside, I use Speedplay pedals on my road bike as I simply like to click in or out without thinking. I do race on Time RXS Ulteams for my tribike because they are sweet and I can actually trot in the cleats without slipping on my butt in T1 if I am lazy and don't want to do a running mount, or can't, because I am not allowed (many races).




People sleep peaceably in their beds at night only because rough men stand ready to do violence on their behalf. George Orwell


jkjt11

Aug 4, 09 21:41

Post #2 of 63 (9598 views)
Re: Speedplay claims huge wind drag reduction... 33 seconds per hour over "leading brands" [stitchboy] [In reply to] Quote | Reply

Blah, Blah-do they provide a fire extinguisher to put out those hot spots?Didn't think so. Next?


Rappstar

Aug 4, 09 21:41

Post #3 of 63 (9600 views)
Re: Speedplay claims huge wind drag reduction... 33 seconds per hour over "leading brands" [stitchboy] [In reply to] Quote | Reply

Lake is the only stock shoe maker that does four-hole shoes standard. But Rocket7 and every other custom maker will do four hole. Some of the shoes with adapter plates (Carnac?) may have four bolt adapter plates.


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stitchboy

Aug 4, 09 21:48

Post #4 of 63 (9579 views)
Re: Speedplay claims huge wind drag reduction... 33 seconds per hour over "leading brands" [Rappstar] [In reply to] Quote | Reply

Thanks Rappstar, I did not know that Lake made four-hole shoes. I guess I am always looking at other brands like Shimano, Sidi, Specialized, etc.. I may need to do some shoe shopping now! No way can I justify a pair of Rocket 7's as much as I would like to. Just curious as to what shoe and clipless system you use?




People sleep peaceably in their beds at night only because rough men stand ready to do violence on their behalf. George Orwell


Rocco69

Aug 5, 09 0:46

Post #5 of 63 (9472 views)
Re: Speedplay claims huge wind drag reduction... 33 seconds per hour over "leading brands" [stitchboy] [In reply to] Quote | Reply

it is absolutely no problem to drill 4 holes into a carbon sole and mount the cleats directly. i have done that with DMT RSX Ultimax and Bontrager Hilo shoes wothout any problems. Just make sure you buy bolts with the correct length.

i love speedplay pedals, both on- and offroad, but the huge time savings seem to me like the zipp crank time savings BS...
:::: Rocco's Studio 69 ::::


stitchboy

Aug 5, 09 1:09

Post #6 of 63 (9457 views)
Re: Speedplay claims huge wind drag reduction... 33 seconds per hour over "leading brands" [Rocco69] [In reply to] Quote | Reply

Are the time savings bogus? I would say I don't really know. It appears Speedplay really tried to isolate the test with as few variables as possible. I think the aero results may fall into the same problem as the Zipp crank. This seems to be a very difficult area to assess as these parts are rotating while being connected to someones legs, which have all kinds of different shapes and efficiency levels. Also some people pedal with toes down, etc..
I would still buy the Zipp crank if it cost about a $1000 dollars less and weighed about 100 grams less. For now I will stick with my "slow" K-Force light (Bonktown $349) and Time pedals.




People sleep peaceably in their beds at night only because rough men stand ready to do violence on their behalf. George Orwell


RobK

Aug 5, 09 1:10

Post #7 of 63 (9456 views)
Re: Speedplay claims huge wind drag reduction... 33 seconds per hour over "leading brands" [stitchboy] [In reply to] Quote | Reply

No mention in their article of sample size (did they do replicate runs? if so, how many?), of whether they used more than one set of shoes of each type (thereby accounting for differences between shoes) or of the statistical significance of the differences they found. 2/10
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Rappstar

Aug 5, 09 8:55

Post #8 of 63 (9102 views)
Re: Speedplay claims huge wind drag reduction... 33 seconds per hour over "leading brands" [stitchboy] [In reply to] Quote | Reply

In Reply To:
Thanks Rappstar, I did not know that Lake made four-hole shoes. I guess I am always looking at other brands like Shimano, Sidi, Specialized, etc.. I may need to do some shoe shopping now! No way can I justify a pair of Rocket 7's as much as I would like to. Just curious as to what shoe and clipless system you use?
Specialized with speedplay. Lake shoes are very nice, though. I rode Lake's for a while and really liked them as well. I'd not hesitate for a moment to use them again.


"Non est ad astra mollis e terris via." - Seneca | rappstar.com | Facebook - Rappstar Racing | @rappstar | WTC Ironman Pro Ambassador

Ask me about: Specialized | Compex 20% OFF - RAPPSTAR20 | Zipp | 1st Endurance | Normatec 10% OFF - RAPP2013 | Quarq | SRAM | ZICO | Smith Optics


GregX

Aug 5, 09 9:01

Post #9 of 63 (9078 views)
Re: Speedplay claims huge wind drag reduction... 33 seconds per hour over "leading brands" [stitchboy] [In reply to] Quote | Reply

i am curious, is the speedplay cleat fundamentally differently shaped when attached to a 4-hole shoe, vs. a 3-hole shoe? anyone know?

i am a little skeptical of these wind tunnel results. because while speedplay pedals are indeed quite small, the speedplay cleat is really enormous, so it seems to me that any so-called drag savings would basically be zero, or maybe 1-2 sec over a 40km TT. anyone have any thoughts? or am i missing something?




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klehner

Aug 5, 09 9:08

Post #10 of 63 (9050 views)
Re: Speedplay claims huge wind drag reduction... 33 seconds per hour over "leading brands" [stitchboy] [In reply to] Quote | Reply

Anyone know if the Speedplay pedals and the "other" (why not name 'em?) pedal systems have the same height, and whether any difference in height affected the drag of the mannequin's legs?

Just curious.
----------------------------------
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Record10Carbon

Aug 5, 09 9:08

Post #11 of 63 (9046 views)
Re: Speedplay claims huge wind drag reduction... 33 seconds per hour over "leading brands" [Rappstar] [In reply to] Quote | Reply

If (and big if) someone had some NOS on a few year old Time or Carnac shoes with the TBT sole...they also had four hole. This would give a much lower stack height....
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What if the Hokey Pokey is what it is all about?


jeremyb

Aug 5, 09 12:37

Post #12 of 63 (8883 views)
Re: Speedplay claims huge wind drag reduction... 33 seconds per hour over "leading brands" [GregX] [In reply to] Quote | Reply

In Reply To:
i am curious, is the speedplay cleat fundamentally differently shaped when attached to a 4-hole shoe, vs. a 3-hole shoe? anyone know?

i am a little skeptical of these wind tunnel results. because while speedplay pedals are indeed quite small, the speedplay cleat is really enormous, so it seems to me that any so-called drag savings would basically be zero, or maybe 1-2 sec over a 40km TT. anyone have any thoughts? or am i missing something?

my understanding is that with a 4 hole shoe, the cleat mounts directly to the shoe, with a 3 hole shoe, the speedplay cleat needs an adapter which adds about 4-7mm? of height.

http://www.lakecycling.com/...-speedplay-p-69.html




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(This post was edited by jeremyb on Aug 5, 09 12:40)


Andrew Coggan

Aug 5, 09 13:33

Post #13 of 63 (8796 views)
Re: Speedplay claims huge wind drag reduction... 33 seconds per hour over "leading brands" [Rocco69] [In reply to] Quote | Reply

In Reply To:
it is absolutely no problem to drill 4 holes into a carbon sole and mount the cleats directly. i have done that with DMT RSX Ultimax and Bontrager Hilo shoes wothout any problems. Just make sure you buy bolts with the correct length.
Into what do the bolts then thread...do you put a T-nut under the footbed or something?


ryancampbell

Aug 5, 09 14:09

Post #14 of 63 (8707 views)
Re: Speedplay claims huge wind drag reduction... 33 seconds per hour over "leading brands" [Andrew Coggan] [In reply to] Quote | Reply

Looking at the test it seems fairly clear that the Cd difference is attributable to the 4mm height difference of the mannequin since that is the only real difference between the 3 hole and 4 hole mountings. Their own test suggests that since there was no significant difference between the 3 hole speedplays and the brand X pedals. The 33 second number is also inflated since the percentage difference wouldn't be that high had they included the whole mannequin and included rolling resistance. Note that the mannequin is only using 54 watts at 30MPH. I'd also like to see margin of error on the tests.

That said, I do believe that there would be a small but measurable aero advantage to dropping 4mm in overall height. Anyone have any more info on modifying 3 hole shoes? Would the footbed curve be compatible?


Andrew Coggan

Aug 5, 09 14:12

Post #15 of 63 (8702 views)
Re: Speedplay claims huge wind drag reduction... 33 seconds per hour over "leading brands" [ryancampbell] [In reply to] Quote | Reply

In Reply To:
Note that the mannequin is only using 54 watts at 30MPH.
Producing, actually.


ryancampbell

Aug 5, 09 14:31

Post #16 of 63 (8658 views)
Re: Speedplay claims huge wind drag reduction... 33 seconds per hour over "leading brands" [Andrew Coggan] [In reply to] Quote | Reply

In Reply To:
Producing, actually.[/reply]Ah, OK, but the point still remains that much of the overall Cd was omitted by loping off the top half of the bike and rider and thus the denominator in the Cd comparison would have been larger. I'm not sure what equation they used to get the 33 seconds/hour and if they took this into account.


Andrew Coggan

Aug 5, 09 14:51

Post #17 of 63 (8623 views)
Re: Speedplay claims huge wind drag reduction... 33 seconds per hour over "leading brands" [ryancampbell] [In reply to] Quote | Reply

In Reply To:
the point still remains that much of the overall Cd was omitted by loping off the top half of the bike and rider and thus the denominator in the Cd comparison would have been larger.

Would it, at least necessarily? There are a lot of people out there with CdAs of <0.25 m^2...


Tom A.

Aug 5, 09 15:12

Post #18 of 63 (8596 views)
Re: Speedplay claims huge wind drag reduction... 33 seconds per hour over "leading brands" [ryancampbell] [In reply to] Quote | Reply

In Reply To:
In Reply To:
Producing, actually.
Ah, OK, but the point still remains that much of the overall Cd was omitted by loping off the top half of the bike and rider and thus the denominator in the Cd comparison would have been larger. I'm not sure what equation they used to get the 33 seconds/hour and if they took this into account.[/reply]
Ummm...doesn't just the absolute value of the reduction (i.e. .005 m^2 of CdA) matter?

That said what exactly does a "time savings of 33s per hour" mean? I don't quite understand that...does it allow you to reach relativistic speeds or something? ;-)

Using the ROT, that .005 m^2 reduction would result in a time savings of ~0.5s per km, or about 20s over 40K.


http://bikeblather.blogspot.com/


ryancampbell

Aug 5, 09 15:13

Post #19 of 63 (8591 views)
Re: Speedplay claims huge wind drag reduction... 33 seconds per hour over "leading brands" [Andrew Coggan] [In reply to] Quote | Reply

Hmmm, good point. Considering the reduced frontal area of the test setup (no shoulders, handlebars, back), that lower body shape must have a terrible Cd compared to a real cyclist to arrive at that CdA. That would also exacerbate the effect of poking that shape up 4mm into the wind.

Anyway, I do believe that there must be some postitive aero effect of lowering a cyclist on a bike, but I'm very suspicious of SpeedPlay's rational for removing parts of the cyclist and bike to remove "extraneous hardware". I certainly don't consider my heart, lungs, and head to be "extranous" :-) I'd suspect that the numbers just turned out better this way.


msuguy512

Aug 5, 09 15:19

Post #20 of 63 (8579 views)
Re: Speedplay claims huge wind drag reduction... 33 seconds per hour over "leading brands" [ryancampbell] [In reply to] Quote | Reply

If you use the 3 hole and adapter you still have a lower stack height then the look pedals. If your theory were true then there should be an even change between look, speedplay w/ adapter, and speedplay 4 bolt but there isn't. Also, if you take a box's frontal area, and the lower the box, its frontal area is the same. The only problem would be if they didn't adjust the stem to match the new stack height which could alter the aerodynamics?

*edit there is no stem, they would need to adjust the saddle height to match the stack height otherwise the data is erroneous. Did they do that?


(This post was edited by msuguy512 on Aug 5, 09 15:21)


Tom A.

Aug 5, 09 15:22

Post #21 of 63 (8577 views)
Re: Speedplay claims huge wind drag reduction... 33 seconds per hour over "leading brands" [ryancampbell] [In reply to] Quote | Reply

In Reply To:
Hmmm, good point. Considering the reduced frontal area of the test setup (no shoulders, handlebars, back), that lower body shape must have a terrible Cd compared to a real cyclist to arrive at that CdA. That would also exacerbate the effect of poking that shape up 4mm into the wind.

Don't forget the wheels used on that setup...not exactly a deep front and a disc ;-)

I'd expect a "full" cyclist on that road setup to have a total CdA closer to .350 m^2 than .250 m^2. The CdA that AC was referring to was a "full aero" TT-type CdA.


In Reply To:

Anyway, I do believe that there must be some postitive aero effect of lowering a cyclist on a bike, but I'm very suspicious of SpeedPlay's rational for removing parts of the cyclist and bike to remove "extraneous hardware". I certainly don't consider my heart, lungs, and head to be "extranous" :-) I'd suspect that the numbers just turned out better this way.

I don't think it's so much about lowering the body relative to the bike or pedals, but more about removing the surface area of the front of the spacer out of the air stream.

It's really about reducing the "A" part of the CdA.


http://bikeblather.blogspot.com/


jeremyb

Aug 5, 09 15:28

Post #22 of 63 (8559 views)
Re: Speedplay claims huge wind drag reduction... 33 seconds per hour over "leading brands" [Tom A.] [In reply to] Quote | Reply

In Reply To:

I don't think it's so much about lowering the body relative to the bike or pedals, but more about removing the surface area of the front of the spacer out of the air stream. It's really about reducing the "A" part of the CdA.

i concur


+1lap: Lightweight Cyclocross Bikes
It's not how fast you go fast, it's how fast you go slow


styrrell

Aug 5, 09 15:39

Post #23 of 63 (8532 views)
Re: Speedplay claims huge wind drag reduction... 33 seconds per hour over "leading brands" [Andrew Coggan] [In reply to] Quote | Reply

I did it to a pair of shoes once. they were Nikes which tend to already be pretty light. I removed the insole and pried up the card board footbed. this allowed me to remove the steel plate that the shimano two hole and look 3 hole cleats bolt to. I drilled 4 holes in carbon sole then used a small triangular file to file the hole into hexagons. I put aluminum mushroom hex head nuts into the holes, put the insole back in and used aluminum screws to put he speedplay cleat on. I had to shim the cleat with some plastic pieces to match the curve of the sole, but between removing the steel plate, eliminating the adapter, and using aluminum hardware it saved quite a bit of weight and lovered me a few mm.

Styrrell
Styrrell


roady

Aug 5, 09 15:41

Post #24 of 63 (8524 views)
Re: Speedplay claims huge wind drag reduction... 33 seconds per hour over "leading brands" [Tom A.] [In reply to] Quote | Reply

In Reply To:
In Reply To:
Hmmm, good point. Considering the reduced frontal area of the test setup (no shoulders, handlebars, back), that lower body shape must have a terrible Cd compared to a real cyclist to arrive at that CdA. That would also exacerbate the effect of poking that shape up 4mm into the wind.

Don't forget the wheels used on that setup...not exactly a deep front and a disc ;-)

I'd expect a "full" cyclist on that road setup to have a total CdA closer to .350 m^2 than .250 m^2. The CdA that AC was referring to was a "full aero" TT-type CdA.


but doesn't a CdA of .234 seem crazy-high for half of a body??? That cut-off torso must have some horrible drag (and is quite freaky-looking)


In Reply To:

Anyway, I do believe that there must be some postitive aero effect of lowering a cyclist on a bike, but I'm very suspicious of SpeedPlay's rational for removing parts of the cyclist and bike to remove "extraneous hardware". I certainly don't consider my heart, lungs, and head to be "extranous" :-) I'd suspect that the numbers just turned out better this way.

I don't think it's so much about lowering the body relative to the bike or pedals, but more about removing the surface area of the front of the spacer out of the air stream.

It's really about reducing the "A" part of the CdA.
are you sure about that?? I remember looking at the flow-sim that Zebragonzo had done, and it sure looked like the bottom of the feet was really messy.


roady

Aug 5, 09 15:45

Post #25 of 63 (8514 views)
Re: Speedplay claims huge wind drag reduction... 33 seconds per hour over "leading brands" [stitchboy] [In reply to] Quote | Reply

my very quick thoughts are that 'pedals probably matter', which is why I use a different pedal/shoe combo for my road bike and TT bike. I don't think they matter as much as is being claimed here, and I'd be pretty curious to see the repeatability of their results, and some more details on the protocol.

I think there are better options out there than Speedplays when it comes to aerodynamics.

I kind of amazed that a pedal company can come up with a pedaling dummy, and bicycle companies can't/haven't? It seems that this would be the holy grail of wind tunnel testing frames/equipment.

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