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It's the end of the road for Nimbus Ti and Nimbus Ti CLD hubs. Read why we are phasing them out on the blog, and snag a set for yourself while supplies last. 

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Tuesday
Jun142016

A Tubeless Primer

Tubeless continues to be the source of a lot of questions, so I thought a brief primer would be in order. 

Tubeless is a subset of clincher, by which I mean that all tubeless tires are clincher tires, and all tubeless rims are clincher rims. A tubeless tire can be used on any clincher rim (subject to a few specific tire/rim fit cases), and a regular non-tubeless clincher tire can be used on any tubeless rim. 

A tubeless (often called tubeless ready) rim has a few specific design features, the critical one of which is the "trough and shelf" design to the tire bed, shown in the red line in the picture below. The trough allows the tire to be installed more easily. When you inflate the tire, the beads get pushed out onto the shelf. The shelf then holds the beads securely up and out, minimizing the chances of air escaping between the bead and rim (the dreaded "burp"). Instead of normal Velox-type rim tape, different non-porous rim tapes are used as well. All wheels we ship have this tubeless tape installed, as we find it also works better in tubed applications than traditional rim strips. 

The red line shows the critical part

Installing a tire (whether tubeless or not) onto a tubeless rim is a little bit more exacting, but is easy with the correct technique. Watch this video to see how we do it. 

The way we think of it, tubeless goes into three categories: road tubeless, cross/gravel tubeless, and mountain bike tubeless. A brief explanation of each follows.

Road Tubeless: Subject to manufacturer interdictions, any clincher rim can be used for road tubeless. You have to prep the rim with an appropriate tape to cover the spoke holes, and you need tubeless valves, which are the same basic valves as you see on inner tubes, only they're not attached to a tube. The valves need to be secured to the rim using a nut. The biggest thing with road tubeless is that you absolutely MUST use tubeless specific tires. The beads on tubeless road tires are reinforced. The beads on regular clinchers are not capable of withstanding the pressure of tubeless use and may blow off the rim. Apart from that one caveat, road tubeless is very easy. Sealant is used to seal the tire/rim interface, and very capably seals small punctures. We're fans of road tubeless. 

Cross/Gravel Tubeless: Cross tubeless is the most exacting tubeless setup. Because the tires are low volume and run at low pressure, the tire/rim interface is critical. With the right combo, cross tubeless can be more secure than tubulars and glue (which is the first time I've said that out loud in public, but it's true). Here is the whole nine yards on what we tested for setups last year. You do not necessarily need a tubeless ready tire for cross tubeless, however we have found that they work much better in general. Based on what we've seen, using non-tubeless rims for cross tubeless is a waste of time - without the shelf design, the tire will burp and you'll be frustrated. Gravel generall uses higher volume tires with more pressure, and less jumping onto the bike and fewer off camber-ific turns, so its much less demanding than cross, but generally similar. We are big advocates of cross/gravel tubeless. 

Mountain Bike Tubeless: This one's pretty easy. I don't even know if you can get a non-tubeless mountain bike rim anymore, and the enormous volume of current mountain bike tires means they've got enough pressure to stay on securely come hell or high water. The lower tire pressure means less bead pressure, so you don't need tubeless specific tires, either. You might need a fair bit of sealant to get some tires to be airtight, but once that's done it's pretty much set it and forget it. It's no wonder that mountain bikes were the first heavy adopters of tubeless - it's so easy and it works so much better than tubes. Mike doesn't really mountain bike anymore and I don't as much as I used to, but I wouldn't go mountain biking with a tubed tire setup. 

In all cases, any flat that the sealant won't fix (and in our experience these are RARE), you just take out the valve and install a tube just like you would a regular flat. Easy peasy. 

Who knows what the future holds for tubeless, but if you're interested in giving it a try it can work really well. 

 

Thursday
Jun092016

Nimbus Ti: The Final Chapter

The Nimbus Ti program has, by any metric, been a big success for us. We’ve sold more wheels, have increased our presence in the market place, have improved our processes and increased our efficiency, and most importantly there are now a whole lot of people riding better wheels than were previously available to them for their price.

The wheel market moves quickly. Component products come and go, supplier relationships change, competitive choices change, and usages change. It wasn’t two years ago that people were just starting to move beyond 23mm tires en masse, and now 25s are scoffed at as anemic.

Among all those changes, there are several factors that make the Nimbus Ti program more challenging than it had been. First, it’s basically impossible to efficiently convince people that the Nimbus Ti hubs are as good as they are. Which they are. But, perhaps owing in large part to our aggressive pricing on them, people view them skeptically and assume that they’re a downgrade to their T11 or CLD equivalents. We simply can’t afford to spend the amount of time that we do making people feel comfortable with saving the amount of money that Nimbus Ti allowed them to.

The second challenge is that people want black hubs. The overall aesthetics of T11s have a bit more pop with the engraved graphics, but in general people just really want black. We suppose we could do Nimbus Ti just in black, but that’s unappealing to us – if it’s going to be black anyhow, we’d just do T11/CLD.

Stay Nimbus, Pony Boy

The third challenge is that the economics of the Nimbus Ti program demand that we’re able to build with something approaching 100% efficiency, but people want choices. Culling the spoke count options down to one or two would have introduced much much more efficiency into the product, but it also would have necessitated compromises that contradict our core wheelbuilding beliefs, so we didn’t do it. The economics of committing to a run of Nimbus Ti hubs gets very shaky when people prefer a wide choice set. But people do want choices, and we want to provide them.

To that end, we’re expanding choices and making it (hopefully) easier to interact with our site to configure exactly what you want. As ever, we are very available to help you decide what setup best fits you and your intended use, usually in real time or something close to it.

The care and craftsmanship that goes into each and every build are daunting. Yes, we can build wheels relatively quickly, but that speed is comparable to how a fast rowing team works: the ones that go fastest look like they aren’t working hard at all, but that appearance hides the mountainous work that went into achieving the level where that can happen, and the real time effort that’s going into it. Literally every build is treated as though it was headed to the world championships. We can never stress that enough.

The most complex challenge is service, by which we mean everything we do from blogs and testing to pre-sales consults, to communication through the order process, to after sales follow ups, to subsidized crash replacements (you people fall over a lot) and soft (basically post-sale communication about use cases) and hard (problems that need to be fixed) post sale service. Fortunately the last one has been rare. We enjoy that whole cycle, think that we’re possibly the best around – certainly near the very top – at it, and we still want to improve at it.  The Nimbus Ti pricing was set at more or less “vending machine” service cost level.  As I described to a vendor just a few days ago, our DNA is to be a “high touch” experience provider, and we love it. But when your A1 resource is time, it’s not free.

 All of our pricing continues to be profoundly consumer-friendly. If we don’t offer the best price on any particular option, we’ll be close. And like any service business – which is what we are – we’ll bet our success that being our customer is a more satisfying experience from tip to tail than you can find elsewhere.

In the meantime, we are making last call on current Nimbus Ti Select and Open product and pricing, and I will say one more time that if the Nimbus Ti fits what you’re looking for, it is the best value around by so much, it’s a little ridiculous. 

Last, for anyone concerned about "what if something happens to my Nimbus Ti hubs," absolutely every part and piece is and has been replaceable with a T11 or CLD equivalent part. No Nimbus Ti hub will ever become an orphan in its lifetime.  

Monday
Jun062016

Gran Fondos and Gran Fondon'ts

Life doesn't often hand me a blog title like that so even if it's not 100% for what I have in mind, I'm rolling with it. This Saturday, my friends Pat and Eric and I rode the Vermont Gran Fondo. It was Eric's first GF, while Pat and I had each done one before. The course is 103 miles with about 10,500 feet of climbing, so while it wasn't my biggest ever day on a bike (the Garrett County Gran Fondo has that honor), it easily slotted into a podium spot in terms of scale of rides I've done.

So why would you do a gran fondo in the first place? After it was over, the three of us settled on a few points. First, it's a chance to do a huge ride that's beyond what you might normally attempt, all in a reasonably consequence-limited environment. Events are generally well supported against mishaps of any kind. Crashes or mechanicals are quickly attended to. You can do a bag drop so you don't have to jam all sorts of extra gear and crap into your pockets. I rode with no more stuff than I'd have taken on a 30 mile after work ride, and if it warms up during the day you can offload your extra gear. Food and drink are taken care of along the route, and you meet a bunch of interesting people, all in an environment where you're not sizing them up to decide how you're going to try to beat them at the finish. And typically the organizer has put a lot of effort into creating a memorable route that you wouldn't necessarily have the knowledge to plan. We ride in the area of the VTGF all the time, and the route took us to places we'd never thought of going - plus it's really hard to go off course. The after ride meal was exceptional at VTGF, and we had a great time at the after party. The entry fees for these typically float around the $100 to $130 mark, so they're not cheap, but some races are already getting up there. "It's a pretty good value for what you get" seemed to be a common feeling at VTGF.

And all the Stonecutter Spirits booze you can drink after the finish!

For gear, I used my disc-braked Timoneria in standard every day setup. Nimbus Ti CLD wheels, with 23mm Schwalbe One tubeless tires installed. Before you ask what kind of an idiot rides 103 miles over a lot of gravel and dirt roads and 5 or 6 huge hills and a bunch of smaller hills on 23s, the 23mm Ones inflate to 26mm. 70psi front and 78psi rear at the start worked great for me. Pat rode his rim-brake Timoneria and Rail 34s. We talked about the ins and outs of using carbon wheels and particularly clinchers before we went, and he made his decision. When you weigh 140 pounds and you set the fastest time up each ascent, you get a little more latitude on wheel selection. I weigh 160 and was top four on the first three (of four) timed ascents but crawled up the last one (more on this in a bit), and was unquestionably the most aggressive descender of anyone we saw all day, and I would not have used carbon wheels with rim brakes for this. Personally, I think at this point if you plan to do this type of riding as your big events and you choose a rim brake bike over a disc bike for your next bike purchase, that's a foolish move. The benefit of disc brakes in this application is profound.

Talking to one of the moto drivers after the event, we learned that there had actually been several fried carbon clinchers during the day. None of them ours, but even with outstanding heat resistance there's only so much you can ask of a carbon clincher, and white knuckling it riding the brakes down an unpaved 15% section just ain't it. We'd ALWAYS counsel using a great set of alloys for these kind of events. 

Eric and Pat looking fresh early onThe one piece of gear that I would have changed was my cassette. I use 50-34 compact cranks, which lulled me into thinking that my cassette choice didn't much matter, and I wound up with an 11-25 (yup) on there, and that makes me an idiot. A little bird told me that Lincoln Gap has the steepest paved mile in the US. That little bird told me that while I was walking up parts of said mile. 75 miles and 9000 or so feet of overgeared climbing in, my legs gave me the middle finger when I asked them to push 34-25 up a 25% grade. 

Sex bombs

None of us wore gloves, which is probably stupid, but none of us had any hand troubles of any sort. The thing that we did all notice was that our feet got a bit worked over by the high frequency bumps on the unpaved descents. Nothing too profound, and certainly on a ride of that magnitude you can't expect it to be all sunshine and puppy dogs, but no way would I do this sucker in shoes that weren't known quantities and really comfortable.

Dave and Pat still looking pretty fresh. We took A LOT of pullsIf you want to have a goal event, or just do something different from the typical race experience, a gran fondo is a great option. In addition to the Garrett County event linked above, people in the northeast can try the Farm Fork series (of which I plan to do at least one or two), while people on the west coat have Phil Gaimon's Mailbu Gran Cookie Dough (which is pretty tempting...) and there are probably a zillion others throughout the country which you can search for here.

See you out there. 

Friday
May272016

Spoke strength and wheel strength

We have a lot of wheels to get out today, so I'm going to publish this without some charts and graphs that I'll add a little later. The words will convery the point adequately enough for the time being, but charts and graphs always make a nice impression on management - those guy are short attention span theater, what can I say?

Anyhow, spoke strength is generally expressed Newtons/mm2. To get the functional strength of a spoke, you multiply that number and the spoke's cross sectional area. A CX Ray has a strength of 1600 N/mm2, and an approximate cross sectional area of 1.98mm2, for a total strength of 3168. I say approximate because I give the cross sectional area as if a CX Ray was a rectangle, but it's actually an oval so my stated cross sectional area is a bit high. The total strength and weight per spoke of an array of common spokes is as follows:

CX Sprint: 3564/5.2g*

Race: 3306/5.7g

CX Ray: 3168/4.25g

D-Light: 2928/4.8g

Laser: 2650/4.26g

*Sapim hasn't published the strength yet, so this is a very conservative but very educated guess

Given these numbers, you can see that if you build a wheel using exclusively CX Sprint or Race spokes, you'd need fewer of them to have the same overall spoke strength. The dynamics of a wheel, however, allow us to engineer a little more elegantly than that. 

The most loaded spokes by far are the rear drive side. They are loaded to the highest tension (around 20% higher than a front spoke, which is next), and are subject to the most dynamic forces. Without adequate total spoke strength (spoke per strength times number of spokes), a rear's drive side spokes will slightly elongate over time, and won't have adequate strength to cope with the dynamic forces that they see. The front spokes are fairly highly tensioned, but a front wheel is symmetrical and doesn't see near the dynamic loads that a rear wheel sees. A front wheel built with 20 Lasers, depending on the rim and hubs used, will do pretty extraordinary duty without batting an eye. The rear non-drive spokes? They're kind of along for the ride. They get loaded to a maximum of 50% of the drive side tensions, they see less torque than the drive side spokes, and the rear hub's left flange placement means that they don't have very hard work to do to keep things in line. 

Given that, you want a ton of total strength on the drive side rear, and you need somewhat less on a road front (disc fronts act similarly to rim brake rears), and you don't need very much on the non-drive of the rear (or non-disc side of a disc front). Against that, you are going to balance weight. The lowest weight at which you can get adequate total strength is the best.

You also have a couple more things to consider. One is points of control. When you build a wheel, the more spokes you have, the more opportunities you have to correct minute rim issues. If the rim has a hard spot, more spokes allow you to taper that correction by making small corrections to several spokes rather than larger corrections to fewer spokes. This makes a better build, and the points of control also work for you in counteracting stresses that the road puts into the wheel. Many hands make light work.

Another thing is simply redundancy. My dad was an aeronautical engineer for his entire career, and did some pretty neat stuff. A trip to Udvar-Hazy with him makes for a very interesting day (and a lot of "I don't know if that's actually been declassified yet"s). Anyway, one of his cliches is that you strive for infallibility but you always use redundancy. If a spoke breaks on a 20 hole wheel, or a 24h rear, your ride is almost certainly toast - this is not a blanket statement but it's generally accurate. The more spokes you have, the less true that becomes. With 32 spokes, if one breaks you rip out the debris and ride on, maybe you have to open your brakes a little. On a race wheel optimized for lightest weight and absolute best aerodynamics, sure fine. On a wheel that you rely on all the time for all of your riding, or on which you are going to go out into remote places beyond "honey can you come pick me up?" Not so much. 

Okay, so that was long, and miles to go before I sleep and all of that, but with that done you have a very good picture of a lot of what we're thinking about in terms of spokes when we recommend a particular setup. 

Have a great Memorial Day weekend, and please keep in mind the staggering volume of day drinking that America does this weekend - please be careful on the roads. 

Thursday
May262016

Wheel Stability

Wheel vocabulary is a challenging thing. The number one thing that people request in wheels is stiffness, of which there are basically three elements - torsional, radial, and lateral. Coming in almost tied with stiffness is the request for light wheels, and then durable, low maintenance, tubeless, all black, etc. The incidence of "how few spokes can I get away with" (always phrased that way) seems to be in decline. 

Torsional stiffness is a wheel's ability to resist deformation from drive train torque. It would take a really bad wheel to have notably poor torsional stiffness. Radial stiffness is your wheel's ability to resist deformation when the spokes face an inward load. People fear too much radial stiffness because they don't want a harsh ride, but a wheel that deformed by 1mm - which is a HUGE amount for a wheel to deform, as the tightest of spokes would go dead slack with 1mm of deformation - doesn't offer anything like the suspension offered by tires. If your wheels feel harsh, we think the tires are the first place to look. Letting 5 or 8psi out can transform a bike. This whole phenomenon is why we got on the wide tires train a long time ago, and then went deep into wider rims right away.  

Lateral stiffness is really two issues. A stiff rim in an underspoked build will stay in plane, but will move off axis relative to the hub. Most "my rear wheel rubs my brake pads" issues are this. A soft rim without enough spokes will come out of plane at the rim, which doesn't evidence itself with brake pad rub, but they'll feel mushy, handle poorly in turns, have poor durability, and other things. Neither is a good situation. This article does a great job with it if you want to go deeper.

English Cycles narrow TT front hub, photo by Bikeradar.com

Recommending a particular build for a particular use has to take in a lot of elements. Rider weight is often the flagship variable, but how a rider rides is at least as significant. If you stand and hammer up every little incline, you place more demands on your wheels than a heavier rider who sits and pedals smoothly. Time trial and endurance event track riders can use front hubs with really close flange placement, which reduce frontal areaand improve aerodynamics. Ride that hub in a crit, though, and you're just not going to make the turns - you'd have crazy understeer. Durability is increased by increasing spoke count, but one size doesn't fit all - for some riders a 20/24 build can be super durable, depending on the components and how they ride. Redundancy is always increased with more spokes - if a spoke breaks in a 32 spoke wheel, your wheel might not even come out of true very noticeably, and that's nice for touring or heavy training in crappy weather or remote locales.

One of the more interesting questions we've been asked recently is why we offer 24/24 and 28/28 in disc, but not in rim brake builds. We didn't know that people didn't know that. The simple answer is that a disc front wheel is dished (the hub flanges are not equidistant from the hub's center), and it transmits torque from hub to rim (because the brakes stop the hub, not the rim). The dish makes the wheel less strong and stable, spoke for spoke, than a rim brake front, while the brake torque transmittal increases the need for strength in the wheel. In a rim brake build, if your front and rear have the same number of spokes, either your front is overbuilt or your rear is underbuilt. In a disc build that's not the case. 

The point here is that no single element exists in isolation; two riders of the same weight could be best off with the exact same build or very different builds, depending on the other criteria. Next we'll look more into spoke type and strength, and balancing spoke, rim, and hub characteristics.