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The Range - our new carbon, tubeless, disc-specific wheelset is open for pre-order, starting at $1285 with White Industries CLD hubs. Shipping in late August, in time for the start of cyclcross, fall gran fondos and the prime gravel season. 

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Tuesday
Jul312012

Fastest Growing Carbon Fiber Bicycle Brand in MD (2 years in a row!)

Yeah, but what does she know about BBQ?Tuesday in Bethesda (the 17th coolest city in America!) is BBQ food truck day. This week's trip served up a tasty pulled chicken sandwich and also a side order of inspiration for today's blog. Get a load of the sign on the side of the truck, and in particular to the product claim at the very bottom. Here's a guy (or a brand, take your pick) who has a sense of humor about product claims and understands their limitations. 

It's almost a consumer requirement to have a sense of humor about product claims, as most are funnier than they are intended to be. If you watched the Tour on TV, you know doubt know which bicycle is "The Best Bicycle in the World." And if you read the trades leading up to the cobbled classics, you may have read the claim that a new endurance road bike was "40% more comfortable" than the road racing model from the same brand. 

The problem I have with product claims is that they usually harvest customer trust instead of grow it. Brands work hard (or spend heavily) to stockpile enough credibility to allow them to take some shortcuts in communicating certain product attributes. When you make the claim that these wheels will save you 30 seconds in a 40K TT, what most brands really mean is that they manufactured an environment in a wind tunnel where the data shows the wheels do in fact save that much time but only compared to a TT ridden precisely at 30mph under constant power and on 32-spoke box rims with a steady 7.5mph wind at a 15 degree yaw angle. The whole truth is more complex, so marketing shorthand is employed.

Most product claims in the bicycle business are quantitative, or at least begin that way. Wind tunnel, stiffness and wheel inertia testing generate a lot of data, and if you're orchestrating these tests there is ample opportunity to develop protocols or comparisons that allow your specific product to shine. It's also not difficult to find a modest baseline which can grossly misrepresent actual performance (the title of this blog is an example, as is the ridiculous Forbes article linked in the first paragraph).

Dave and I are spending a lot of time talking about product claims because we'll soon be running some quantitative tests of our own. But our conundrum is not how we'll make our stuff look the fastest, stiffest, awesomest or otherwise mostest. Rather, we're trying to figure out how to communicate the results transparently and even-handedly, avoiding shorthand but not getting too much in the weeds of detail that the results themselves disappear. We want to educate our customers of the process as much as the results, and incorporate enough context and perspective so you see what we see, not just what we want you to see. 

Put another way, we want our claims to build customer trust in our brand, not take advantage of it. I have to add another sentence to this paragraph or Dave will skewer me as a 1-sentence paragraph hack. 

So I did.

Monday
Jul232012

The Magic of Front Brakes

We see a lot of wheels.  Just yesterday, I pulled into the BP station at Falls and River in Potomac (home of the world's coldest water fountain - inside the right hand bay next to the door to the office) and of the 9 bikes in the parking lot, I'd built 4 of their wheels.  That kind of stuff happens with some regularity, so you wind up seeing a lot of wheels and checking in on them.  One thing that often concerns me is that it's always the rear wheel that's got more brake track wear than the front. 

We had a customer contact us a few weeks ago and say that while he loved his 58s, an injury pretty much precluded him from doing any more racing, he was getting more into charity rides and gran fondo type stuff, and could we do a swap for some FSWs.  This is the kind of thing that really benefits everyone, so we said yes, and he sent his wheels back to us.  For how long he'd used them, they looked awesome (I put about an eighth of a turn on one spoke, mostly because I felt like I probably ought to do SOMETHING), but the thing that impressed me most was that his rear brake track literally looked brand new.  The front looked like it hadn't been used as much as the front I've been using for about a year, but it showed wear.  The rear was spotless.  Someone who really knows how to brake!  BTW his wheels already have a new home. 

Next time you are standing by your bike, do this simple test: grab the rear brake and push the bike forward.  The rear wheel skids and the bike goes forward largely unimpeded.  Now grab the front brake and push the bike forward.  The bike goes nowhere and the rear wheel lifts off the ground.  The front brake is (scientifically speaking) about a Brazilian times more effective than the rear at slowing you down or stopping you. 

Assuming that most of you did the same dumbass thing that I did when I was a little kid and slammed on the front brake real hard and went flying over the bars one time, then your hesitation with the front brake is more than understandable.  However, you really need to put that behind you.  Gently push back as you apply the front brake and your weight will stay balanced exactly where it should be, and you will slow down faster and more effectively by far. 

Two caveats - 1) overuse of the front brake on a cross/mountain bike may lead to you sucking and/or needing new teeth and 2) beware the front brake in turns.  Beware both brakes in turns, but especially the front.  A rear wheel skid is often a recoverable deal, while front brake skids almost always result in you making a tarmac inspection.  Which is a big part of why you want to brake BEFORE the turn.

If it hadn't been totally raining on Saturday we would have had a nice video of descending and braking, but alas the video looked a lot like wet lens and spots of color.  Good braking fundamentals become even more important in the wet. 

But if you're doing it right, your front brake gets most of the workout. 

Monday
Jul162012

What Do Sail Trimmers Have to Do with Wheels?

Last time, we chewed on some points about aero wheels, but time ran long before I got to dive into what happens between 10 and 15 degrees angle of incidence or apparent wind angle.  If you look at the chart, you'll see that there is a dramatic - nearly vertical - increase in drag for most wheels somewhere between about 10 degrees and 15 degrees.  In the case of the Stinger 7, you have about a 150 gram drag (or approximately 15 watts) difference between 15 and 17.5 degrees of wind angle.  A 2.5 degree windshift is NOTHING, they happen continually.  Also, if your speed is constant but wind speed increases, the apparent wind angle will widen since it is a vector sum (to figure out what your apparent wind angle will be in various situations click this link and substitute bike speed for board speed.  Tacking angle will be the angle between where the wind is coming from and your direction of travel - so if you are headed due east and the wind is coming from due north, your tacking angle is 90*).  As you lay with that page, notice that as wind speed increases relative to bike/board speed, apparent wind angle widens.  Increase board/bike speed and it narrows.  This relates to why I postulated that a HED H3 is an attractive wheel for fast riders in light winds even though it has a narrow range of superiority. 

Back to sail trimmers - what have they got to do with it?  Well, just like the wheels in our chart, a 2.5* difference in sailing is HUGE.  If you take a competitive but unexceptional boat and improve its ability to sail close to the wind by 2.5*, that boat is going to have an awful lot of trouble ever losing a race.  Since sailboats have to tack upwind, the speed they go through the water converts into speed directly into the wind as a function of the cosine of their angle relative to the wind.  If boats A and B are going through the water at 10 knots but boat A is only able to get as close as 38* while boat B is able to get 2.5* closer, boat B will essentially go .3 knots faster into the wind.  After a half an hour, boat B is going to be .15 nautical miles (or 910 feet) ahead of boat A.  Setting aside the issue of the tactical opportunities that this kind of advantage would give you, a 910 foot advantage on a typical 30 minute upwind leg is an ass whooping.  There are also a lot of boats that have "cliffs" just like you see in the wheel chart - a 2.5* difference in your angle to the wind is going to be enormous.  In some catamarans, it's not unrealistic to say that a 2.5* change in your angle to the wind could change your boat speed from 6 knots to 18 knots. 

THE BIG POINT BEING that a 2.5* window of resolution, in wind terms, is not very precise at all.  A wheel that's working just awesomely at 14.9* apparent wind angle might fall off that cliff at 15.1*.  No hyperbole at all there.  The lines are sharp.  A talented sail trimmer could, by very gingerly changing the wheel's apparent wind angle, keep the flow attached for a valuable few portions of a degree, or maybe even a degree, and change relative positions of one wheel to another on this chart quite dramatically. 

I'm not saying that this happens.  Since real world conditions when you are not trimming sails see much more herky-jerky changes in apparent wind angle, the best protocol is to blast air at wheels at wind angles of a somewhat (but as you hopefully now see, not very) precise window of resolution, and graph them from there.  Basically what I'm saying is that some wheels very clearly have windows in which they are psychotically low drag, and the approximate relative places along both the horizontal axis are noteworthy.  A wheel with a wide strip of really low drag numbers is a good aerodynamic choice, but saying that one wheel is better than another because it shows its cliff 1* or 2.5* further out on the horizontal axis is a lot less significant.  Rounding errors and test noise can make the relative differences between two wheels look a lot more different on a chart than they might act in the real world. 

Believe it or not, I have no ulterior motive in this, no desire to see one wheel's apparent relative strengths augmented or diminished.  You get wheels that show really low drag numbers (relative to other options - the H3 never gets absolutely low but it does get relatively low) across a band of 7.5 or 10 degrees, that wheel has got some strengths.  But this does also show that we aren't talking about "I WAS GOING 1 MPH FASTER THAN WITH MY OTHER WHEELS" in any case.  We're talking about differences of, in big cases, 15 watts.  If I could have or not have 15 extra watts, I'd take them.  And after an hour I'd be more than a couple of bike lengths ahead of where I'd be without them.  In a lot more cases we're talking about 4 or 5 watts, which again you'd rather have than not have but the benefit can be very malleable in a dynamic environment.  Those of you who are familiar with how agonizingle obtuse I can be will think that no topic gets raised without a reason, but reason and motive are not mutually inclusive. 

Wednesday
Jul112012

Do Aerodynamics Matter?

Okay so the title is a bit sensationalist but I wanted it to balance my last post which was titled "Does Weight Matter?"  I don't think there are many people left who would argue that, as far as aerodynamics go, the more the better.  It is, however, still subject to the "all else being equal" deal.  Just because your bike may be set up in an aerodynaically sound way doesn't mean that you are aero on it - think "slam that stem" with a guy barely able to put his fingertips on his bar tops.  

In any case, the TTs at the Tour always provide a good chance to think and talk about aerodynamics and aerodynamic equipment.  Wheels are the obvious choice to focus on since they are visible and they are generally the only components that is commonly measured by themselves.  Front wheels are more constructive to look at since rear wheels are so often rebranded in ways that cloud their provenenance, and the aerodynamics of the rear wheel are accepted as playing a very second fiddle to those of the front.

The following chart (hopefully it follows - I'm having trouble formatting it on this page) shows the drag values of a bunch of wheels across various angles of incidence.  These are commonly called "yaw angles" but that is one misnomer (along with "deep dish wheels") that I just can't abide.  Apparent wind angle, angle of incidence, whatever - it's NOT yaw.  The wheel is identified, and the source of the data is in parentheses - so there are two series for 404s, one produced by Zipp and one that uses Bontrager's data.  The data sets all appear on the source websites.  10 grams of drag is closely equivalent to 1 watt, so if the difference between 2 wheels at a given angle is 40 grams, then the one wheel will take approximately 4 watts more to go the same speed as the other. 

Click to make huge.

As we now know, Wiggins and Froome handed out pretty substantive ass whoopings.  They both did so using the old standby HED H3 wheel, of which there are two models - the H3 and the newer H3D.  I don't know which they used, but it's somewhat immaterial.  As you can see in the chart above, the H3 models do well at low wind angles - going straight into the wind, they are great.  As the wind angle widens, they do less well.  Notably, they are crazy consistent across wind angle bands - no matter where the wind's coming from, they are what they are.  But at a lot of wind angles, the H3s apparently leave a lot of grams of drag on the table.  So why do the Sky guys use them, and how are they able to use them so well?

For one thing, Wiggins and Froome HAUL ASS.  When you go 30mph on a nearly windless day, your apparent wind angle is constantly "darn near zero."  So they were probably confident that on that day, they were using the wheels at their best. 

For another, very deep front wheels have interesting handling characteristics.  I haven't ridden a ton of deep fronts, but I've ridden enough to know that they generally have a gyroscopic effect that makes turning a bit of an adventure.  The TT course had a lot of twists and turns, and TTs are far from purely watt and aero contests.  Good TT riders display technique in corners and over rises and dips that help them conserve energy and maintain high speed. 

Yet another factor is how the wheels work with the bike.  It's all well and good to evaluate wheels in isolation but there's plenty of research now (ENVE has been a leading proponent of this) that says that the pairing of bike and wheel can be a more significant factor than the wheel itself.  Given Sky's tendency to sweat the small stuff, I'm guessing that they know that the HED H3 works just fine thanks with their Pinarello TT bikes. Anecdotally, Wiggins always seems to use this wheel, so there may be a factor of preference at play as well.

Cancellara was third in the TT, using a Bontrager Aeolus 7 front (he may have been using an Aeolus 9 - it's a bit hard to tell).  In any case, whether 9 or 7, Bontrager's data shows that the wheel Cancellara used is really good at the 5 to 12 degree angles that you often see when you're going fast.  Anecdotally, Cancellara seems to always use this kind of wheel (he used 808 fronts an awful lot when he was on Zipp sponsored teams), so again we see that there might be some personal preference. 

Tejay Van Garderen was fourth on what appeared to be an Easton EC90TT, which is a 56mm front wheel.  There's not a lot of aero data out there on the Easton but it has a decided "v" shape - more so than any other rim I know of, and it's narrow.  This would imply that, like the H3, it is relatively stronger at low angles of incidence and relatively less good at wider wind angles. 

Fifth was Sylvain Chavanel, on an 808 front, and between the Bontrager and the Zipp I would say you are probably splitting hairs.  The shape of their curves is quite similar, but the differences between the Zipp-produced data and the HED-produced data are interesting.  I'd love to tackle this topic now but since I am well over the word count which our data shows produces an alarming trail off in reader interest, I will instead tease for a next installment - "tune in next time for another thrilling episode, entitled what the hell do America's Cup sail trimmers have to do with how data is produced in a wind tunnel?"

Monday
Jul022012

Does Weight Matter?

One of the things I go back and forth with is the question of how much weight matters.  It's a funny thing, because it's the most objectifiable thing on a bike.  Impressions of geometry and handling will vary from person to person, stiffness can be quantified but more is not always preferred for every rider or circumstance, aerodynamics are debated and argued in various ways, aesthetics are a whole other kettle of fish, but put a bike on a scale and there's only one number that's going to come up.  All else being equal, the lower that number, the better. 

In a world where your like or dislike of a certain golf club is as related to its sound as to its performance, and where cyclists may not have the breadth or depth of experience with different bikes to be able to really pin down their likes and dislikes in the way different bikes handle, it's not unusual that people would place a lot of importance on something that is as readily quantified as weight.

On one hand, I think that perhaps the way that weight's effects are calculated to a racing cyclist understate its importance.  Sites like Analytic Cycling allow you to plug in weights versus coefficients of drag so that you can see that, in general, aero does indeed trump weight.  But aero benefits are measured in a static wind tunnel, and as you can see if you look at charts and graphs from various wheel companies, even the wind tunnel benefits are hard to nail down.  Put them on the open road and it gets fuzzy indeed.  You'd have to have your head buried pretty far in the sand to deny that there are valuable benefits available from aero equipment, but to quantify it is rather difficult.  Part of this comes from manufacturer claims - the chuckles about the new aero cranks that save you 20" over a full Ironman course (winning Ironman bike splits are roughly 4.5 hours, so this represents a .1% improvement) were pretty loud.  So it's hard to know just how much benefit you are getting from aero equipment.  You know you're getting some. 

On the other hand, the static way in which weight is measured probably understates its practical effect just as the wind tunnel likely overstates practical benefits of aero gear.  Most calculations talk about static grade, constant speeds, etc.  That doesn't line up at all with most of the climbing experience I've had - grades constantly change, attacks come and go, etc.  Even on flat courses, you are constantly changing speeds.  I'm guessing that the difference between say a 1500 gram set of wheels and one a quarter of a pound heavier will leave you with more than .1% extra in the tank at the end of the race. 

The question is of course one of degree.  People chase weight to pretty crazy degrees.  On this boat I used to sail on, we had a saying - "grains of sand."  What this meant was that if you added up enough tiny little grains of sand, you'd eventually wind up with the Sahara desert, so we were always looking for the small gains.  No one carried any superfluous stuff when we raced.  But I recently read a comment somewhere that called 10 grams of difference between two sets of wheels a notable difference.  In my mind, I struggle to call a .7% difference in weight between two sets of wheels notable.  Wheels aren't grains of sand - they're often or even usually the heaviest component on the bike.  This apart from the fact that a 10 gram difference is WELL within the weight variance tolerance of any wheels. 

Bikes used in road races aren't allowed to weigh less than 14.8 pounds.  They often do, since when was the last time an official weighed a bike at a race, right?  I know a lot of people get their bikes down to like 13 pounds, and there are multiple websites devoted to the practice of getting your bike down to the lowest weight possible. 

Weight is something that we always look at every time we evaluate something, and we recently chose not to go ahead with some new rims because we thought their weight penalty outweighed the benefits they brought.  Soon enough I am sure that we'll have the need to evaluate weight versus other factors in other products, and despite weight's objective measurement, we will have to evaluate it subjectively in the mix of other factors.