The Stiffness Saga, Pt. 1: Rims

If you've never read it, Edward Tufte's book The Visual Display of Quantitative Information is definitely worth a look.  With all of the info that we're shaking loose from our wheel stiffness testing and measuring, it's definitely a challenge to parse it out into pieces you can actually chew.  This project has actually made me need to go back and digest what it is I've thought I've learned several times.  

Since the wheels we make are really nothing if not assemblies of components, it's worth it to talk about the components themselves.  You have rims, hubs, and spokes.  Each affects the system, but they all work together.  You do a bunch of horse trading back and forth to try and tease out the biggest spike of the features you want to maximize, while paying the lowest cost in negative features like weight and drag.  

Once you have the right fixtures, it's easy to measure rim stiffness.  You support the wheel at 3 o'clock and 9 o'clock, and load it at 6 and 12.  Measure the deflection under load et voila, there you go.  A few pieces of aluminum extrusion, a weight, and a dial gauge were all we needed for this one.  

We measured every type of rim we have on hand, except the Iron Cross rims because some dummy already built them into wheels and can't wait to use them.  Mike channeled his inner Edward Tufte and this came out:


All of these are 700c/29" rims (which is why the Stan's Crest isn't there - some dummy ordered the wrong size of those).  Note that we have plotted them against weight, so the bias line you see is stiffness to weight ratio.  On the line can be said to have average stiffness to weight, above the line can be said to have good stiffness to weight, and below the line can be said to have less good stiffness to weight.  

Rail 34s do quite well measuring this way.  

Now, of course, stiffness to weight isn't the only important thing in a rim.  The Rail 52 is fundamentally a pretty similar structure to the Rail 34, but pays a weight cost for its depth and shape.  That depth and shape come with the benefit of making it among the fastest wheels anywhere near its depth (and any clincher near its weight).  Conversely, the Stan's 340 comes with a very light weight.  Light riders who aren't slapping out watts might not need all that stiffness, and can benefit from lighter weight.  And a Stan's 340 with a good hub and an appropriate spoke count can be a quite stiff wheel - a 28 spoke Stan's 340 was a standout in whole wheel testing.  In the case of the Arch EX, we're building those with 32 spokes, not the 20 spokes that a Pacenti SL23 front might have.  And it needs to durability as well as stiffness - the two are neither mutually in- or exclusive.  The Kinlin XC279 which has been the basis for our FSW23 wheel has a nice mix of all of the attributes.  

We'll talk about hubs and spokes individually before we get into the whole assembly, and note that this is lateral stiffness.  Radial or circular stiffness is another thing that we'll talk about.

All of these measurements take massive mounts of time - building wheels, configuring the test apparatus, etc etc etc, so this will come over some time period.  But we're happy to be out of the land of guessing and into the realm of knowing.  


What Are We Riding?

These guys are teed up for a lot of upcoming milesWith so many options available to us, a lot of people wonder what Mike and I actually ride.  For the most part, we're pretty boring.  I'm still on the Rail 34s with WI hubs that I started with in March.  Nearly 3000 miles later, I love them (more on this later).  Mike anxiously awaits the return of his 34s, but has mostly been on a set of 52s.

Since our first week with the wheel deflection testing rig has opened up more questions than it's given us answers (this is a good thing, I assure you), and since we want to get more up close and personal with a few of the more popular custom alloy setups, and since cross season and a marathon mountain bike race are coming up, it's time to branch out a bit.  

Mike's chosen a set with Stan's 340 rims, 24/28 lacing, with red White Industries hubs, black CX Rays, and gold nipples.  I presume he chose this color combo to accentuate the quite cool graphics on the rims.  For road, I'm getting onto a set built with Pacenti SL23s, 28/32 lacing, black WI, silver CX Rays, and red nipples.  We'll each spend some time on the ones we've chosen, probably switch and compare notes, and then move onto another build. 

The Iron Cross set above will be my main cross wheels.  I'm going all tubeless this year.  For mountain biking, I'm going with a set built on Arches for my 29er.  Disc for cross wouldn't actually be my first choice, but I sold my beloved HOT BUNS to my buddy Raul after last year.  He wanted a pit bike, and I don't think he needs to turn a single wrench to set up my bike for himself - our setups are nearly exactly alike.  

Is our love affair with Rails cooling?  No. But we both pretty well know how they behave in any situation possible, and having learned that it's time to broaden our experience.   

So, after 3 months and change on 34s, here's a brief review.  First, I love the way they look, for whatever that's worth.  My road bike is well into its 4th year and I should be bored with it, but with 34s on it, I still love to look at it.  As far as being "daily drivers," they've been used in the complete array of conditions including monsoons, mountains, crazy amounts of wind, gravel roads, crits, road races, mellow rides, you name it.  They feel plenty fast, which the wind tunnel will either confirm or bust soon enough.  They laughed off being driven into a pothole that sprained both of my thumbs (neither of which is yet back up to speed), as well as another pothole that pinch flatted a tubeless tire (yes, seriously).  They corner flawlessly.  I've done most of the miles tubeless, which was great with Hutchinson tires.  After the aforementioned tubeless pinch flat, I switched the rear to a Michelin Pro4 with a tube.  A piece of glass put that tire on death watch the other day.  If I were made to use only 34s for the rest of my riding days, I'd be more than cool with that.  

What do they do wrong?   Not much.  Braking in a downpour isn't great.  It's functional, and combined with the SwissStop pads it's better than any carbon wheel we'd previously made, and let's face it braking on a road bike in a monsoon isn't so super fantastic in any case.  

Headed to VT later in the week for the field portion of our Rail heat test, combined with a photo shoot and some actual honest-to-god training.  Speaking of photos, check out the old (brand new) Instagram.  Haven't got a ton of photos up yet, but they're coming day by day.  


Units Of Measurement

These turn out to be pretty stiff, indeed. Yesterday, I finally worked through some final details of our wheel deflection measurement jig.  The jig lets us precisely measure the lateral deflection of any wheel with a quick release hub that fits 9mm or 10mm dropouts.  This covers most wheels, including every wheel we've ever sold (fronts are 9mm, rears are 10).  After way too long of a day yesterday, we were able to measure several front wheels and are already learning a bunch.  It will take time, but the plan is to evaluate everything; rims, hubs, spoke count, spoke type, lacing - everything.   

The remaining problem with the whole deal is developing an effective way to quantify and communicate the differences between wheels.  As it is now, we could take a wheel that deflects, say .092" in our protocol, and compare that to another wheel that deflects .125", and say that the first wheel is 25% stiffer than the second (difference between the two, divided by the deflection of the second).  We could even say the first is 35% stiffer, by taking the difference between the two and dividing it by the deflection of the first.  This second way is the way that's used whenever you buy any consumer product that claims to give you "25% MORE FREE!" or whatever.  Some similar methodology is used when, for example, a 2015 model year crankset is compared to a 2014 model year crankset, in order to show the greatest improvement.  A 30% increase in stiffness is impressive, right?  

Unsurprisingly, we don't plan to do that.  The goal of this whole exercise is to help us to guide you in selecting the best wheel for you and the plans you have for it.  We know, through a few years of subjective testing, that there are wheels that are empirically "stiff enough for whoever wants to do whatever with it," and that there are wheels whose lack of stiffness compromises their performance.  So if we take the former wheel and call that a 10, and we take a wheel that's just at the margin where any further loss of stiffness would really hamper it and call that a 3, that seems more useful to us.  It leaves some space below the range for any true bombs we find, and provides enough granularity that the differences between one wheel and another actually show up.  There's no established protocol, and no standardization of measurement tools, so any comparison of absolute values is the height of worthlessness.  We have measurement precision, but slightly fuzzier relative values are much more valuable in this case.

Added to what we've learned (and continue to learn) in the wind tunnel, this all gives us a profound ability to help you decide which components and build are right for you.  The development of this testing tool has been an obsession of mine for about a month, and now that it's done I've got the latitude to start measuring more parameters.  Brake heat development in real world conditions and time to stop measurement are up next.  Mike's a little freaked out about the bills I rack up at McMaster, so it's definitely time to pick some low-hanging fruit for a while (fortunately I already bought the heat scanner, so I don't have to worry about that one).  

A couple of quick codas to add.  First, having made something as cool as our rig is, you might expect us to blow up the internets with photos.  Nope.  This thing took a long time, a pile of money, a bunch of wrong turns, and several dropped curse words to develop, and having it is an advantage for us.  Second, while we have no plans to go out and buy a pile of wheels (or even any wheels) specifically for the purpose of comparing what we do to what's on the market, if you possess a wheel that you'd like to get measured, we're happy to do it.  Contact us and we'll arrange it.   Last, thanks to Justin at Octo for helping me to figure out how to put this contraption together.  The notes I've got from this round give a huge headstart on the next few measurement fixtures.



As Is The Custom...

Just a taste of what's to come

Say what you will, but those Alphonse commercials were about as funny as it gets.  Freaking hilarious.  Anyhow, the custom on today's agenda doesn't refer to societal norms and standards, but rather completely non-standard wheels.  Wheels created precisely for you.  

As November has grown, people have consistently asked for a broader range of options, and now we're happy to say that we're in a position to offer a huge array of hubs, rims and spokes, all built and serviced how we do it.  Of course we'll still offer standard builds in order to get your wheels to you in less time than it's ever taken us to do it, but our lead time for options and custom is less than it's been too.  We're now in a position where taking a bigger inventory risk isn't very risky, which allows us to get you what you want quick, fast, in a hurry.  

We're continuing to increase the scope of our testing, as well as our ability to present you with the most applicable info possible, which will help you make the best selections for your use.  A comprehensive trip to the wind tunnel is days away, our wheel stiffness test rig is under construction, and brake heat testing that will actually give you usable information is underway.  The wisdom of experience and educated guesses are important (we've got those, too), but it's always nice to back them up with the hard currency of good data, and the data often surprises.  And I promise that you can count on us to recommend a few more rear spokes than others might tell you you can "get away with."

Our web store has already undergone some changes and more are in stock in the coming days.  

Lastly, after today's newsletter, it appears that we will have a riot on our hands if we don't sell the socks.  We weren't 100% sure we were even going to sell them, but in the interest of the public's safety, we will.  They are in the souvenirs section of our web store.  


The Wind Cries Tunnel

A boring weekend in the life of 34s, what with our budding NRC star enjoying a well-deserved weekend with her toes in the sand and a fruity blender drink in her hand.  Lacking any local races to do myself, I took my 34s for a 70 mile cruise of the south coast, whereupon I averaged comfortably in excess of 20mph and reconfirmed that if solo centuries were a valid from of racing, my standard of mediocrity would be several levels higher than where it currently stands.

Your guess is as good as ours

In addition to shipping a bunch of wheels (sun shining, hay making, etc) we're currently prepping our next trip to the wind tunnel, which will take place soon.  This will be the first time we've sent a pair of 34s, and we're doing better than sending one - we're sending two pairs.  One of the burgeoning questions around disc brakes on road bikes is how well or poorly they perform aerodynamically.  While the results should stand as a definitive answer for "how does a 24 spoke 34 equipped with disc brakes compare to a 20 spoke 34 equipped for rim brakes," it will be a pretty good proxy for the general question of "what's the aerodynamic cost of disc brakes in on wheels in general?"  The wheel we're sending has a White Industries CLD hub, using a 160mm SRAM rotor.  Tunnel time costing what it does and our interest in this question being enough to send a disc-ready 34 but not enough to exhaustively test every conceivable permutation out there, this will be what we test.  

As we've said a bunch of times, the mandate of the 34s is quite a bit beyond simply being an aerodynamic sensation.  That's way higher up on the job list for 52s than 34s, so while verifying the speediness of 52s before we put them into production was an absolute requisite, it hasn't been so urgent for 34s.

This will also be the first trip that a production 52 has made to the tunnel.  If you'll recall, when we first tested the 52, we sent our pre-production prototype, fondly dubbed Canary Thunder.  Canary Thunder had 24 spokes rather than the standard 20, and was a little rough of finish.  We'll be testing it against the same benchmark 404 that we send last time (same wheel exactly, as correct protocol would mandate), so we'll have a good reference benchmark back to the original test.  This will give us a slightly dirty answer to the question of how 4 extra spokes affects a 52 specifically, intermixed with some noise about how a yellow plastic prototype compares to a full production wheel.  

There will be a few other wheels making the trip, some of which will be making multiple runs to answer more of the world's burning questions, and you can be sure we're going to drag this one out into a bunch of blogs to ensure that any at-work time in July that you're not spending glued to the Tour will be spent glued to this site.  As it should be.

How about that Talansky, huh?