I did something similar once comparing 404 clinchers vs. 404 tubulars, which at that time had a weight differential of nearly a full pound (~400g). I compared like tires and tubes on each (Vittoria Corsa CXs with latex tubes) and assuming the tubulars were glued in a "typical" fashion (i.e. not necessarily for absolute lowest Crr).

In that analysis, it took grades of OVER 8% before the total "demand" (i.e. aero+rolling resistance+mass) of the tubular setup drew even with the clincher model. In other words, at every grade below that amount, the 404 clincher setup was faster despite being nearly a pound heavier.

Although that's not exactly what you were looking for, it should put the matter of wheel weight and it's effects on bike performance in perspective.

Now then....I like your question...and I think I'll have to somehow incorporate it into an article I'm writing on wheel weight/inertia and it's effects (or, non-effects) on bike performance :-)

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http://bikeblather.blogspot.com/

Thanks for the reply. I like my question too, which is why I ask it :) * My suspicion is that the "climbing" wheel will rarely be faster (no matter how "good" it allegedly feels). The obvious people to make this kind of analysis would be the manufacturer (like Cervelo did). On the other hand, ultimately they want to sell more wheels, so if they find that their "climbing wheel" is not as fast over a typical col as their "aero" wheel, then it's hard to justify selling both kinds of wheels...

*With a personal motivation of the mountainous sportives in my region. Also, if I ever decide to go back to the Marmotte, I want to be prepared...

Tom- a follow up question. Why was the clincher setup faster? Is it purely because the tubular wasn't superglued to the wheel, thus raising the CRR?

Yup.

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I agree with your assesment. Choice of wheel should come down mostly only to wind, and how much you want to fight the front wheel. An ironman athlete might not want to fight an 808 for 6 hours on a windy day. So go 404.

An exception would be a bike racer who specifically looks to break away from the pack on steep climbs. Such a rider might want to go with a 202/303. Sure they may only save him 2 or 3 seconds even on a 12% grade, but that might be just what he needs.

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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

I know what the science says and I agree with it, for controlled, laboratory conditions. But when it it comes to cycling outside in real world conditions I think there are just way too many variables that cannot be tested or even accounted for...the biggest being the human engine. That's why there is always arguments over these issues and nothing can be proved clearly enough to satisfy everyone. It's always going to be subjective with each rider using what they "feel" is best.
Having gotten that out of the way, I've always "felt" I've ridden fastest with lighter wheels as I rarely ride on flat ground for very long. As I ride because I like it, although there are often times when I want to stop the suffering of hard efforts, I care more about what feels good as it adds to the overall enjoyment of my riding. If I obsessed over the science too much it would take the fun out of it and I wouldn't ride. I use shallow section wheels, deep section wheels and disc wheels but have always used the lightest of the category. The lightest have always been tubulars but now that full carbon clinchers are available I have been riding on some Reynolds DV46 clinchers for the last year. The nice thing about the technology now is you don't really need to compromise much anymore...you can get very aero AND very light now in either tubular or clinchers. However, cost is the difference if you want aero and light as full carbon rims are still fairly pricey.
Nobody will ever convince me that equally aero wheelsets are equal out on the road if the weights vary by more than 50 grams.

Bottom line is: Ride whatever makes you feel good and quit trying to force people to believe what you believe...this is cycling people, not religion or politics!

Greg.

If you knew before hand that a Super Glued Tubular is faster than a non Super Glued Tubular, why would you test a non Super Glued Tubular to a Clincher?

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I know enough to know I don't know enough...

The "human engine" cannot be tested or accounted for? Really? Last year I finally put a power meter on my bike; testing is training and training is testing and, to be honest, after a while I found that my performances were shockingly predictable. Such that, when I did a mountain road race, drafting, hiding, following wheels and surges when I could, my normalized performance was exactly what I would have expected from my FTP.

(Also, clearly I'm not asking about "equally aero wheelsets" of different weights.)

I understand what you're saying...but, part of my motivation for the article I'm writing is to address the fact that MANY times people attribute something being, or "feeling", faster to the weight or inertia, when more likely any differences they feel are due to aerodynamics, or even just rolling resistance differences.

The "religion" part of all of this is people believing that weight is a PRIMARY determiner of wheel performance, when demonstrably (using SCIENCE!) it's a much "lower order term" in the equation.

It's not about forcing people to "believe what you believe" since it's only about "beliefs" on one side. The other side is merely using logic, science, and actual measurements to show "what is what" and then letting folks decide for themselves.

That said...as far as riding "whatever makes you feel good" goes...Yes, the placebo effect is real and can be strong. That's why it's controlled for in any study that deals with human perceptions ;-)

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http://bikeblather.blogspot.com/

That speaks more to the qualities of "everyone" than it does to the quality of the evidence. Anyway these questions need not just be answered on paper, or even in a laboratory. It is pretty easy to figure out if a 404 or 808 is faster up a hill, and by how much by testing them in the real world, with a power meter.




No, the clever riders will trust careful measurement over feel.

Honestly, not trying to be rude, buy saying up front, that nothing and nobody would or could convince you of this, is willful stupidity.


Sound to me like with your willful decision to be ignorant, and preference for emotions over data and math, that you think cycling is very much like religion and politics!

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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

Sigh...I didn't test anything. This was just an analysis based on the AFM's roller testing...and, IIRC, at the time of the analysis he actually had not yet "discovered" the secret of "excessive gluing".

Secondly, IME, most tubulars in use (especially for triathletes) are glued closer to what I had originally assumed in the analysis than by AFM's 2-3 tubes of Mastik 1 per tire (!) technique for optimum tubular Crr.

Even so, the point of me bringing it up in this thread is that obviously the differences in Crr between a less than "optimally" glued tubular and an equivalent clincher setup with a latex tube isn't going to be a HUGE amount...and yet it still took grades of OVER 8% before a total mass difference of ~400g in the wheelsets brought the tubular wheelset JUST EVEN with the performance of the clincher setup based on that admittedly SMALL difference in Crr.

That's what I meant about putting wheel mass effects on performance "in perspective".

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http://bikeblather.blogspot.com/

A well-planned and executed road test or two would help you get over that "belief" hump and more readily accept the science. Those of us who have been around cycling for a long time had it drilled into our heads (and sometimes OUT of our groupos!) that weight was such a huge factor...and consequently it sometimes takes a while and some scientific sledge hammers to get those notions put into their correct places.

"Nobody will ever convince me that equally aero wheelsets are equal out on the road if the weights vary by more than 50 grams." A lot of people refused to believe the earth was round or was not the center of the universe, let alone the solar system. Science has demonstrated that conclusively. But if you and I were simply left to our own devices (and lacked prior learning of the solar system, galaxy, universe, etc)...our senses...and the feel of the earth around us...we might still conclude the earth is flat and the center of all. We truly do have a hard time disbelieving our senses even when confronted by superior evidence to the contrary.

Today we are lucky enough to have devices readily available that can help us disabuse our own faulty senses of notions like 50 grams on a wheelset is going to matter more than other, higher order effects like Crr. You can even do these tests in the "real world" and still come up with the same answers as the math and controlled lab environments.


(Also note that Tom's test used a "typical" glue job (I assume he's meaning a typical TRIATHLETE's glue job), and not a good road/track glue job which can bring the best tubulars right inline with the best clincher/latex tube setups.)

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I remember doing a similar analysis of the cost of carrying more weight around a course. The energy cost to lift the extra weight up the # of metres of climbing on the course is very easy to calculate since E=mgh. You could then express this in time at a given power output to the road. I recall something like 35-40 seconds over a rolling IM course like CDA at 200W for the weight difference between tubulars and clinchers (clearly less than the Crr difference between a fast clincher w/ latex and a "glued so I can still change it" tubular).

However, this is a worst case scenario because assuming the descents are straight (no braking), some of that energy would be reclaimed on the way down (since heavier objects with equal aerodynamics descend faster in air). Exactly how much energy is reclaimed (and how much is lost to air resistance) is not so easy to calculate, at least for me. Do you have an equation, or a rule of thumb, to at least get a ballpark #? It would be good to know if it was 10%, 50% or 90%, particularly when deciding whether to worry about carrying heavy conveniences like extra fluid weight around the course.

It's my experience that RARELY do even those glue jobs approach the amount of glue shown by AFM to give the higher Crr for tubulars.

That said, nobody really knows where the "tipping point" of glue amount lies...and that's actually something I've had on my plate to try to figure out for awhile. I've got all the materials necessary, I just need to carve out the time to do it ;-)

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http://bikeblather.blogspot.com/

I'm pretty thick at the best of times Tom..but could one infer that the CRR of a clincher with latex tubes will (more than likely) be better than that of the 'average' similar weight tubular..unless glued to death? If that is the case..and most people can't/don't glue their tires on to the point of sandblasting for removal..is the aforementioned clincher set up not the wheel set up of choice? Perhaps it's time for some clincher updating..any recos for tire choice?

It's probably best (and conservative) to just ignore that since aero drag force increases with the square of the velocity.

Other than that, if you want more detail you'll be spending some "quality time" with the equation of motion of a cyclist, which can be found in a bunch of different locations...

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Again...it's NOT about the "weight" of the tires, it's about that slightly more difficult property to measure, Crr. So yes, an equivalently constructed clincher will, in general, be faster than the similarly constructed tubular setup when taking into account how they are normally run (especially by triathletes). This is why both I AND Rappstar (I think he still agrees with me) don't see any compelling reasons for the average (or even FOP) age grouper to be running tubulars.

As far as recommendations go, look at the ones near the top of AFM's Crr listing and pick one that meets your own personal requirements of speed vs. durability...oh, and don't forget to match the widths to your rim width for best aerodynamics ;-)

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http://bikeblather.blogspot.com/

HED has made some claims for its aero wheels:

The first Aero clincher wheels, ever since 1990. The new 60mm aero section made specifically for the C2 rim make the Jet 6 better than ever. They're more aero, they roll better, corner better, and they're lighter. Even in crosswinds, the Jet 6 wheels are fast, it takes a strong crosswind to stall them out. These wheels have won everything from local crits to the Ironman World Championship.
Climbing? They're plenty light for climbing. We modeled a rider on our power/drag software to illustrate it. The model rider goes 190lbs total bike and rider weight, and we gave him 275 watts, pointed him into a 9kph headwind. We calculated two sets of numbers, one on 1320g wheelset with the drag characteristics of traditional low profile wheels, and a 300g heavier wheelset with the drag of Jet 6s. The lower drag of the Jets kept our model rider going faster until the grade reached 7.5%. Unless your race is all uphill in the mountains, Jets are going to get you to the finish faster.

They fudged a bit by adding a slight headwind, but the general conclusion that aero wheels are faster (even for climbing) is valid. For reference, the average grade of l'Alpe d'Huez is 7.2%.

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ECMGN Therapy Silicon Valley:
Depression, Neurocognitive problems, Dementias (Testing and Evaluation), Trauma and PTSD, Traumatic Brain Injury (TBI)

It did seem odd to me that you would test something that you knew wasn't worth testing. Thanks for clarifying...
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I know enough to know I don't know enough...

Wow. Who pissed in your corn flakes this morning. Nice of you to use words like stupid and ignorant replying to me. I think I made it pretty clear that I was giving my opinion on my own experience. What did you find so offensive that it required such a polite reply? I didn't dispute any of your scientific data or beliefs. I Maybe you should work on your reading comprehension.

As you're such a superb teacher and example of forum protocol I will try and get this part correct. First I'll quote you, "not trying to be rude", and then I'l actually be rude. Now when I see Jackmott, I will think Jack Ass, as your head is obviously stuck way too far up there to have a reasonable conversation.

Greg.

Thanks for that, kind of thing I am looking for. So, to bring it up to date, how about a 2011 Stinger 40 vs 2011 Stinger 60 (weight delta of 50 g per pair according to Hed website)?

I made it clear what I found offensive. What I found offensive was the statement "Nobody can convince me otherwise".


Sometimes the truth is inherently rude. You openly stated that you would refuse to be convinced of something. That is an illogical attitude. You speak of having reasonable conversations - how can that happen when you refuse to be convinced of something?

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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

Jackass,

You didn't take my advice on reading comprehension. Go back and read my post. I said EQUALLY aero wheels. One is ALSO a little bit lighter. My statement that you quoted refers to this fact. Get it through your thick head that we now have the choice to get aero AND lighweight wheels in one! You only need to choose aero OR light if cost is an issue.

And about "the truth being inherently rude", pick up a dictionary, there is a big difference between rude and unpleasant. The truth can be unpleasant but it can't be rude. Jackmott on the other hand IS rude.

Greg.

You are right, my mistake. I humbly and publicly apologize.

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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