Re: Dimond wind tunnel data is finally available to the public [AaronT] [ In reply to ]

Jul 25, 14 4:24

Post #26 of 47 (4377 views)

AaronT wrote:

corneliused wrote:

So on chip seal roads with large rocks, you don't suppose adding suspension will make a difference? The effect is noticeable in grass with highly inflated tires.

Like, say, the rocks found in the Arenberg Forest? Bike companies have tried adding suspension over the years, but guess what keeps winning? Regular road bikes with big, fat, low pressure tires.

Solid logic. If many pros win on non aero frames, frames touted for their increased vertical compliance, then aero frames must be slower right?

Just ask superdave: http://forum.slowtwitch.com/...um.cgi?post=4673798;

Re: Dimond wind tunnel data is finally available to the public [Borden] [ In reply to ]

Jul 25, 14 5:31

Post #27 of 47 (4343 views)

Borden wrote:

Seat of the pants dyno says
I did go 26mph avg on the rolling course of an Olympic bike split on just 260W AP. I thought that was crazy low wattage for the speed.

just wanted to add.................. it's not anywhere near crazy low wattage

Re: Dimond wind tunnel data is finally available to the public [rruff] [ In reply to ]

Jul 25, 14 6:17

Post #28 of 47 (4297 views)

Interesting is one way of putting it. Its little wonder he had problems replicating it between runs. My guess is they moved him around until the numbers were optimized on the Dimond and then tried to replicate that position on the Shiv and P5. I also suspect if when you start adding stuff to the frame (spare kit, hydration, nutrition...) the integrated storage options for the P5 and Shiv will cancel out the Dimond's frame only benefits.

Re: Dimond wind tunnel data is finally available to the public [Borden] [ In reply to ]

Jul 25, 14 6:18

Post #29 of 47 (4297 views)

Borden wrote:

Tom A. wrote:

Not the same. When isolated to deflections in the tire, when using tires with excellent Crr, that means a good portion of the energy put into the tire in the leading half of the contact patch is actually returned to the road surface in the trailing half with the small hysteresis losses in the material actually resulting in the "reverse torque" about the wheel axle that we experience as rolling resistance.

So the great benefit of snazzy tires and tubes is the energy return as the rider moves beyond the deflection point in the tire?
And
The beam simply damps vertical ossiclations of the rider? You don't think there is any benefit as the beam rebounds?

It doesn't matter what I think...like I said above, show me the data! :-)

http://bikeblather.blogspot.com/

Re: Dimond wind tunnel data is finally available to the public [corneliused] [ In reply to ]

Jul 25, 14 7:10

Post #30 of 47 (4241 views)

corneliused wrote:

AaronT wrote:

corneliused wrote:

So on chip seal roads with large rocks, you don't suppose adding suspension will make a difference? The effect is noticeable in grass with highly inflated tires.

Like, say, the rocks found in the Arenberg Forest? Bike companies have tried adding suspension over the years, but guess what keeps winning? Regular road bikes with big, fat, low pressure tires.

Solid logic. If many pros win on non aero frames, frames touted for their increased vertical compliance, then aero frames must be slower right?

Just ask superdave: http://forum.slowtwitch.com/...um.cgi?post=4673798;

Talk to me about the science supporting your suspended road bikes. Apples : Oranges here, bud.

Re: Dimond wind tunnel data is finally available to the public [Borden] [ In reply to ]

Jul 25, 14 8:21

Post #31 of 47 (4183 views)

Are you saying the frame reduces rolling resistance somehow?

Borden...tell them about lower rolling resistance...[/quote wrote:

EDIT - nevermind - read the rest of the thread :)

Last edited by: TH3_FRB: Jul 25, 14 8:44

Re: Dimond wind tunnel data is finally available to the public [rruff] [ In reply to ]

Jul 25, 14 9:07

Post #32 of 47 (4132 views)

rruff wrote:

The head position is interesting also...

It's the Faster tunnel... is it maybe not large enough to avoid interference effects with a rider? I've heard this tunnel is relatively poor, anyway.

Odd that even though the results with rider were inconsistent, the P5 was consistently bad. And the Shiv pretty good.

The important part. Seems like a fast bike though. Controlling rider position is pretty difficult. But that tunnel though...

Re: Dimond wind tunnel data is finally available to the public [James Haycraft] [ In reply to ]

Jul 25, 14 9:28

Post #33 of 47 (4109 views)

Data on why the Faster tunnel is "relatively poor", or just opinion?

James Haycraft wrote:

rruff wrote:

The head position is interesting also...

It's the Faster tunnel... is it maybe not large enough to avoid interference effects with a rider? I've heard this tunnel is relatively poor, anyway.

Odd that even though the results with rider were inconsistent, the P5 was consistently bad. And the Shiv pretty good.

The important part. Seems like a fast bike though. Controlling rider position is pretty difficult. But that tunnel though...

Re: Dimond wind tunnel data is finally available to the public [Ironwimp] [ In reply to ]

Jul 25, 14 11:05

Post #34 of 47 (4031 views)

I think it's great that they're putting the data out there. It is clearly a fast bike, but I am going to look at any data put out by a manufacturer with some skepticism.

One question I would ask is how they selected the aerobars for each bike. The Profile Design Volna is not the stock bar on the P5, and as far as I know the Zipp bars are not stock on the Shiv. The Volna is an integrated bar so they might have had to rotate the basebar up to achieve the desired hand position. It does have ski-bend extensions so it might not have needed much upward rotation, but it still puts the Magura brake levers in a really bad position - much worse than the stock Aura bar. The angle of the extensions on the Dimond can be adjusted independently of the basebar, so the basebar can be kept horizontal while the extensions are rotated upwards to their desired location. This could be a big deal if the basebar on the P5 is rotated upward and stalling.

It seems to me that they should have selected the stock bars on each bike and duplicated position as closely as possible between them, or even better used the same setup on each bike. I don't know the specs or price points on the Dimond Standard or Premium builds, so I don't know where they are trying to compete exactly, but I would also question whey they used the P5-3 rather than the P5-6.

Anyway, I'm not trying to nitpick. I think they are beautiful bikes and I'm sure they are a blast to ride. I just question whether the aerodynamic differences are as significant as they claim.

Re: Dimond wind tunnel data is finally available to the public [dkidwell] [ In reply to ]

Jul 25, 14 11:11

Post #35 of 47 (4023 views)

I agree Derek. If you want fair testing, keep the bikes stock. Otherwise it appears you are tweaking the test to make your bike look better. I don't trust any data from any manufacturer unless it's backed up by independent testing

Make Inside Out Sports your next online tri shop! http://www.insideoutsports.com/

Re: Dimond wind tunnel data is finally available to the public [TH3_FRB] [ In reply to ]

Jul 25, 14 17:52

Post #36 of 47 (3911 views)

It's a really small tunnel front to back and side to side to quote Easy E. If you look at some of the other tunnels, the entire FASTER tunnel would fit in between the screen at the front and the plate the bike sits on.

Brian Stover USAT LII
Accelerate3 Coaching
Insta

Re: Dimond wind tunnel data is finally available to the public [corneliused] [ In reply to ]

Jul 25, 14 18:26

Post #37 of 47 (3892 views)

corneliused wrote:

AaronT wrote:

corneliused wrote:

So on chip seal roads with large rocks, you don't suppose adding suspension will make a difference? The effect is noticeable in grass with highly inflated tires.

Like, say, the rocks found in the Arenberg Forest? Bike companies have tried adding suspension over the years, but guess what keeps winning? Regular road bikes with big, fat, low pressure tires.

Solid logic. If many pros win on non aero frames, frames touted for their increased vertical compliance, then aero frames must be slower right?

Just ask superdave: http://forum.slowtwitch.com/...um.cgi?post=4673798;

In a pool of 2 frames that may be true, but it is not true of all frames. For example, the AR is more vertically compliant than the F series yet the AR FRD and F FRD have the same HT and BB and 2 stay torsional stiffness. F is ~300g lighter for the frameset and AR is ~300g "more aero" @50kph -15/0/15.

-SD

Re: Dimond wind tunnel data is finally available to the public [SuperDave] [ In reply to ]

Jul 25, 14 19:08

Post #38 of 47 (3870 views)

were can you actually pack food, hydration, spare tubes on this frame? Sweet looking frame though!

2024: Bevoman, Galveston, Alcatraz, Marble Falls, Santa Cruz

Re: Dimond wind tunnel data is finally available to the public [nebeachbum] [ In reply to ]

Jul 25, 14 19:26

Post #39 of 47 (3858 views)

nebeachbum wrote:

were can you actually pack food, hydration, spare tubes on this frame? Sweet looking frame though!

Click the first link below for a pic of the race setup.

2 levers, tube, co2, and chuck under the seat
I get 5hrs of nutrition BTA

In training, a rear hydration setup with 2 cages wags water.

@christopher_borden •
Spinning Spoke • Dimond Bikes • Flo Cycling • Castelli Cycling

Re: Dimond wind tunnel data is finally available to the public [SuperDave] [ In reply to ]

Jul 25, 14 19:53

Post #40 of 47 (3840 views)

SuperDave wrote:

In a pool of 2 frames that may be true, but it is not true of all frames. For example, the AR is more vertically compliant than the F series yet the AR FRD and F FRD have the same HT and BB and 2 stay torsional stiffness. F is ~300g lighter for the frameset and AR is ~300g "more aero" @50kph -15/0/15.

-SD

To put those numbers from Dave above in context, the 300g of mass difference would require ~1W difference in power when climbing an 8% grade (I assumed 85kg bike+rider climbing at 4m/s, ~290W), whereas even at that low speed the 300g of drag advantage would actually gain that 1W back...while at all other speeds the gains of the lower drag AR would be dramatically higher. Just plug the numbers into Analyticcyling.com and see for yourself.

For example, 300g measured drag difference is ~= 33W lower power when riding at ~24-28mph to go the same speed for the AR as opposed to the F.

Understanding the above numbers, it's pretty clear that the real purpose of one of the frame sets is to appeal to the "sensibilities" of those who feel a bike should have round(ish) tubes to "look right".

http://bikeblather.blogspot.com/

Re: Dimond wind tunnel data is finally available to the public [dkidwell] [ In reply to ]

Jul 26, 14 6:14

Post #41 of 47 (3716 views)

Maybe cervelo can lend them foam Dave. Damon told me they have to keep Dave nude or even the wrinkles in the clothes foul up the testing.

I agree with whoever posted claiming time savings without rider is lame.

Re: Dimond wind tunnel data is finally available to the public [Mdfletcher] [ In reply to ]

Jul 26, 14 14:42

Post #42 of 47 (3649 views)

Mdfletcher wrote:

Maybe cervelo can lend them foam Dave. Damon told me they have to keep Dave nude or even the wrinkles in the clothes foul up the testing.

I'd like to see a shootout between the new Plasma 5, Dimond, P5-6, Shiv Tri, and new Speed Concept with Foam Dave on top. Get all of the superbikes together and let them duke it out.

Re: Dimond wind tunnel data is finally available to the public [writhe] [ In reply to ]

Jul 26, 14 15:05

Post #43 of 47 (3629 views)

That will never happen. Each manufacturer wants to be able to say "WE HAVE THE FASTEST BIKE IN THE WORLD. IT SAVES YOU 1000 JIGAWATTS OF POWER AND IS RICKY BOBBY FAST!"

Make Inside Out Sports your next online tri shop! http://www.insideoutsports.com/

Re: Dimond wind tunnel data is finally available to the public [BryanD] [ In reply to ]

Jul 26, 14 15:28

Post #44 of 47 (3612 views)

BryanD wrote:

That will never happen. Each manufacturer wants to be able to say "WE HAVE THE FASTEST BIKE IN THE WORLD. IT SAVES YOU 1000 JIGAWATTS OF POWER AND IS RICKY BOBBY FAST!"

But someone with no chips in the game could do just that independently.

-Of course it's 'effing hard, it's IRONMAN!
Team ZOOT
ZOOT, QR, Garmin, HED Wheels, Zealios, FormSwim, Precision Hydration, Rudy Project

Re: Dimond wind tunnel data is finally available to the public [Bryancd] [ In reply to ]

Jul 26, 14 15:30

Post #45 of 47 (3611 views)

Triathlete magazine could

Make Inside Out Sports your next online tri shop! http://www.insideoutsports.com/

Re: Dimond wind tunnel data is finally available to the public [BryanD] [ In reply to ]

Jul 26, 14 16:31

Post #46 of 47 (3574 views)

tour magazine does it all the time

Kat Hunter reports on the San Dimas Stage Race from inside the GC winning team
Aeroweenie.com -Compendium of Aero Data and Knowledge
Freelance sports & outdoors writer Kathryn Hunter

Re: Dimond wind tunnel data is finally available to the public [BryanD] [ In reply to ]

Jul 26, 14 16:43

Post #47 of 47 (3569 views)

BryanD wrote:

Triathlete magazine could

Triathlete magazine relies on those same companies to heavily for add revenue. They lack the intestinal fortitude to be so bold.

-Of course it's 'effing hard, it's IRONMAN!
Team ZOOT
ZOOT, QR, Garmin, HED Wheels, Zealios, FormSwim, Precision Hydration, Rudy Project

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