the burden of proof lies with the person making the claim that those are better than the current aero wheels.

I can say I've never seen independent data. Which to me makes them not proven. I seem to recall something from Madfiber along the lines of "we didn't design the wheel with regard to aerodynamics(no windtunnel designing or CAD), but when we stuck it in the wind tunnel it did pretty good, so that's nice."

I know I've only seen what they put on their site, which means NOTHING because they don't say what wheel they tested against, and it does the worst in the most common yaw conditions, 5-20 degrees. Whats even more laughable is that instead of giving data as to what yaw matters, i,e, going out and sampling or looking at weather conditions, or anything. They say its where their wheels do best. PFFFF.

Not one major proven cycling company would claim that 20 degrees of yaw is the most important yaw angle. I'm guessing that many would vary on placing importance on 5-10 v. 10-15 but none would suggest that 20 is really what we should focus on.

Now, I'm guessing the wheel that it was tested against was the old 808. But we also don't know what tire was used. Was it wide, or narrow? Was it a clincher 808 or tubular? Was it the same tire?

Finally, if you are with Madfiber it would be best to disclose your position in MadFiber wheels on your "signature" when you post.

The good news is that the construction technique looks like it would be more adept to running changes in differing rim shapes. I would encourage Madfiber to really actually use some CAD or wind tunnel time to refine their wheels.

My understanding is that the construction method actually makes if very difficult for a change in rim shape. The spokes enter the rim parallel with the V-shape and are bonded over a large area to the inside of the rim. If the shape was more aerodynamic like a toroidial profile, that curvature would inherently weaken the wheel because of how the loads are transferred from the rim to the spokes. The rim itself doesn't even sound like a traditionally molded rim as well, in the video posted below at 2:20 he mentions that the rim is constructed in three pieces.

http://www.youtube.com/watch?v=g9pjSP97PNc

It will be interested going forward to see what changes they make, but I see these wheels competing with the Edge/Enve and Lightweights of the world rather than the Zipp's and Hed's.

Here is a starting point. The math is pretty to the point.
http://www.analyticcycling.com/WheelsConcept_Page.html

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Yeah, it's a great bike but the engine needs work.

particularly if he were...say to hold the title of Director of Sales at Madfiber?

Times 10....to many amateurs spouting their mouth about shit in the real world that they don't understand.

Are you kidding me? You should be the ST poster boy for spouting your mouth about stuff you don't understand.

Who is this jackmott anyway....every answer and that is practically every post uses data that doesn't apply in real situations.
Mad Fiber wheels definitely have their place. I would put them even with a pair of mavic ultimates for a best set of very fast wheels
for situations where you need intense acceleration and lightweight.


I'd definitely like to have a pair in my stable

I guess that is why I still dominate.

Take this how you want. I got a chance to see the madfiber wheels at NAHBS and first impressions were that these wheels are LIGHT. The process to make the wheels is unique in that they use a higher compression to create the carbon fiber pieces and then glue them together to make a wheel. The engineer who they have working on the wheel design is an engineer for Boeing and has been using composites in aircraft construction for years. This has given them a different way of looking at the construction of the wheels with the spokes being glued to the face of the hub and rim. As far as the flexibility of the wheel the explanation that I was given was that they like how it rides, and its based on the personal preference of President Ric Hjertberg. He did say they could make the wheel stiffer but haven't done so yet because they like the current feel of the wheel. Ric founded wheelsmith, and is also the importer of Ghisallo wood rims from Italy through the Wheel Fanatyk brand.

-Mark

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http://www.ventuscustoms.com Custom Bicycle Painting.

Are you kidding me? You should be the ST poster boy for spouting your mouth about stuff you don't understand.

If you had any clue about the racing pedigree and accomplishments of the person to whom you just said that, you'd be REALLY REALLY embarrassed.

well a) he's not doing himself any favors by changing his username every 2 weeks, and b) even Jordan Rapp has tried to gently suggest that perhaps Mr. Patterson succeeds in spite of , rather than because of his technical acumen.

you saw the wheel weight math yet you still dont believe?

Exactly my problem with ST....spouting with zero real facts.

are you suggesting something I wrote isn't true?

well a) he's not doing himself any favors by changing his username every 2 weeks, and b) even Jordan Rapp has tried to gently suggest that perhaps Mr. Patterson succeeds in spite of , rather than because of his technical acumen.


I'm proud to say I've become friends with Mr. P over the last few years and, while I ordinarily respect Jordan's opinion, I can't agree with his assessment in this case. John's technical accumen would make any STer proud. (When I raced against him back in November, I was in awe of the bike he'd put together for the occasion.) It's just that John has decades of racing experience that act as a pretty good bullshit filter.

60/66 1085gr........stiff as a rock.....
This is one bad ass set of wheels.

They are indeed way to HOT for a triguy...and I don't mean that in a ugly way.

They are just not the Stinger90/disc combo that you need.

"while certainly not perfect, I'll take my math over a million human perceptions *any* day.

until such time as someone chooses to prove me wrong by careful measurement, I'm pretty confident I'm right here. I think in fact this notion has been proven right already by careful measurement by zipp, biketechreview, and maybe tom?

a light wheel *will* let you go quicker, but not substantively more so than a light skewer, or stem, or ass."

Okay I'll check your math.

From another thread:

I can't believe that people keep arguing that rotating mass climbs slower than non-rotating mass under the same power. When you are working against gravity, mass is mass, it doesn't matter if it rotates or not. The idea that micro-accelerations due to pedal force fluctations make a difference in the overall picture is a strawman. During pedal force fluctuations, accelerations are decelerations cancel out. All that really matters is average power output vs. gravity.

Thats not what our perception is about. In real riding you are constantly accelerating from say 15 mph to 30 mph. Corners, attacks, the pack bunching up, etc. Any while the light vs heavy difference may not be big, when you have to close a little gap to catch a draft a bunch of times in a crit, that adds up substantially. Frankly the microacceleration thing is a strawman, thats not the acceleration that you are worried about in a race.


Since Ras11 complained that no math has been offered, I decided to set up a model to simulate the accelerations/decelerations due to pedal fluctuations. The equations and variable values were taken from the Analytic Cycling web page.

Pedaling force: The propulsion force (from pedaling) was modeled as a sinusoidal. Since it is assumed average power is constant, the nomimal drive force will vary inversely with velocity. So, the propulsion force is modeled as:

Fp = (P/V)(1+Sine(2RT))

Fp = Propulsion force (pedaling)
P = Average power
V = Velocity
R = Pedaling revolution rate
T = Time

(Note: The angle in the sine term is double the pedal revolution rate, since there are two power strokes per revolution)

The drag forces on the rider are aerodynamic drag, rolling resistance, and gravity. These three terms together are:

Fd = (1/2)CdRhoAV^2 + MgCrrCosine(S) + MgSin(S)

Fd = drag force
Cd = Coefficient of aerodynamic drag
Rho = Density of air
A = Frontal area
M = total mass of bike and rider
Crr= Coefficient of Rolling Resistance
g = Acceleration of gravity
S = Slope of road

The total force is thus:

F = Fp - Fd

From Newton's second law, the equation of motion is:

dV/dt = F/I

I = Inertia

Because there is both rotating and non-rotating mass, total mass and total inertial will not be the same. Because mass at the periphery of the wheel as twice the inertia as non-rotating weight, the total mass and inertia of a bike are:

This is not necessarily correct. Distance from hub matters alot.


M = Ms + Mr
I = Ms + 2Mr

Ms = Static mass

Mr = Rotating mass

The complete equation of motion is thus:

dV/dt = {(P/V)(1+sin(2RT)) - [ (1/2)CdRhoAV^2 + (Ms+Mr)gCrrCosine(S) + (Ms+Mr)gSine(S) ] } / (Ms + 2Mr)

This is a good model, but not necessarily complete, it has a lot of assumptions.


This equation is non-linear, so I solved it numerically with a 4th order Runge-Kutta numerical differentiation.

Borrowing the default values in the Analytic Cycling web page for "Speed given Power" page, the values used are:

P = 250 Watts, Cd = 0.5, Rho = 1.226 Kg/m^3, A = 0.5 m^2, Crr = 0.004, g = 9.806 m/s^2, S = 3% (= 1.718 deg.)

(http://www.analyticcycling.com/ForcesSpeed_Page.html)

For this simulation, the pedal revolution rate was selected as 540 deg/sec. (90 rpm cadence)

To solve this equation, a 4th order Runge-Kutta numerical differentiation was set up using an Excel spread sheet. Step size was selected at 0.01 sec., and the initial Velocity was 1 m/sec. The solution was calculated for 3 cases of equal total mass, but different distributions of static and rotating mass, calculated over a 200 second period, by which time each case had reached steady state. As expected, the velocity oscillated with the pedal strokes. The average, maximum, and minimum velocities during the oscillilations during stead state were:

Case 1:
Ms = 75 kg, Mr = 0 kg (0% rotating mass)
Average Velocity: 7.457831059 m/s
Maximum Velocity: 7.481487113 m/s
Minimum Velocity: 7.434183890 m/s
Speed fluctuation: 0.047303224 m/s

Case 2:
Ms = 70 kg, Mr = 5 kg (5.33% rotating mass)
Average Velocity: 7.457834727 m/s
Maximum Velocity: 7.480016980 m/s
Minimum Velocity: 7.435662980 m/s
Speed fluctuation: 0.044354000 m/s

Case 3:
Ms = 65 kg, Mr = 10 kg (10.67% rotating mass)
Average Velocity: 7.457837584 m/s
Maximum Velocity: 7.478718985 m/s
Minimum Velocity: 7.436967847 m/s
Speed fluctuation: 0.041751139 m/s


Again your model assumes that weight taken off the wheel, is put back on the bike. Of course you get small difference. You are solving for 0 weight loss and micro accelerations.

What do you get for 170 pounds of bike and rider vs a 168 pound bike and rider in a 50 lap 4 corner crit, where the heavier rider has to put out more power to make up the difference in time for 200 corners of say 20 to 25 mph accelerations?

Styrrell

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Styrrell

you saw the wheel weight math yet you still dont believe?


I fell asleep during that lecture. I also missed the one about how many angels can dance on the head of a pin.

Has Mad Fiber made any claims to be the best aero wheel on the market? I realize this is ST where if it ain't aero it aint worth it. But there are a number ofreal world riding situations where aero isn't the most important aspect of a wheel.

The goal of Mad Fiber was to make the best all around wheelset on the market, a wheelset that could handle climbing in the morning, TT in the afternoon and a crit in the evening. There are more aero wheels on the market, but they are considerably heavier. There are lighter wheels on the market but they have rider weight limits. There are stiffer wheels on the market but they are heavier. We feel we have achieved the goal of making a lightweight, stff, strong, aero wheel.

Personally I have been in the industry a long time but I have never seen any "independent wind tunnel data" on wheels that is truly worthwhile. Contrary to popular ST belief, getting real world data from a wind tunnel on wheels isn't as cut and dried as ST'ers think it is. And as I stated in the above post, aero isn't "the" most important design feature of our wheels. The vast majority of the riders out there are looking at a "complete" all around wheelset.

At some point we will have a marketing department to come up with cool charts, graphs, and acronyms for "features". Right now we don't have one. We are just trying to make the best all around wheel at a good price point so all riders can have fun riding and going for their personal goals.

Yes I do work for Mad Fiber as the Director of Sales (and international sales and shipping department and customer service department and warranty department and receptionist). You can take a look at my profile here find my real name, know where I live, what I do and how to contact me directly. You can see the bikes that I ride even though I need to update them. So I didn't think I needed to call out what I do. Unlike some people here, I am not hiding behind an anonymous name. Plus I am sort of busy during the work day (when I orignally responded) and I may have dropped my normal routine of actually using my name to sign my posts.

Thanks.
Steve Dempsey
Director of Sales
Mad Fiber.

I probably was not clear enough. I was not necessarily criticizing your testing. I wanted to know the specifics so that I could actually understand it. I had questions:

1. what tire was used?
2. was the same tire used on both wheels?
3. what do you have as support for your contention that 20 degrees yaw is the most important yaw angle for riders to consider?

It's not a matter of me criticizing your aero testing. You're right in that most St'ers couldn't run the average testing session, me included. However, realistically not giving the specifics of your test doesn't help your credibility at all. Tire type and size should have been on your website when you posted the data to begin with.

As for independent data that carries weight. I feel that Velonews did a good job with their aero testing and also allow a certan amount of subjectivity as you suggest as valuable. Tour also has merits with some caveats. Both very valuable for a discerning customer.

Also, your attitude towards ST comes off as quite condescending.

whats not real world about yaw sweeps to 30 degrees?

in terms of performance, AERO is the most important feature.

im getting sick of people perpetuating the myth that weight is significant. if youre sacrificing any amount of weight for aerodynamics youre doing yourself a disfavor.
stiffness? hed jets and zipps are plenty stiff and have options likely stiffer than mad fibre.

Thanks for setting these mindless morons straight.
You have THE BEST SET OF ALL-AROUND WHEELS on the market currently.

I'll switch these for a pair of MF's if you want some exposure winning races.
Yes...those are rainbow stripes...earned on the guy behind me.

the only moron here is the one who resorts to ad hominem arguments and thinks physics doesnt apply to him.