Random Thoughts on Bicycle Wheels
One word: awesome.
RIM BRANDS CHASING ECONOMIES OF SCOPE
I find this annoying. Very annoying.
There are fewer rim manufacturers that have rim-only offers in their assortment. Many have moved to selling complete wheels exclusively. I understand the commercial rationale very well. I cannot fault them for chasing economies of scope. However, as a consumer, they are severely limiting our range of choice in the market. For example, if I wanted Zipp rims laced to Chris King hubs using Sapim spokes, I cannot do that. It’s because Zipp, like many other better rim brands, offer only complete wheels. (Not that I want Zipp rims as I cannot warm up to those dimples that make them look like they are suffering from an unpleasant and contagious malady.)
One of the last upmarket rim brands that still have rim-only offers is Enve. They also offer complete wheels with either Chris King or DT Swiss hubs. Now, Enve are offering their own hubs too: ‘All About Road Hubs‘.
It is no surprise that they included Zipp hubs in the test, as taking a shot at what I am guessing is their most important competitor would be logical. It is difficult to know if the tests were unbiased, but I was not surprised to see that Zipp performed extremely poorly. I always thought that Zipp hubs look like an afterthought. What surprised me was how poorly White Industries performed.
Enve now offer the choice of selecting Enve, Chris King or DT Swiss hubs for their builds. However, I would not be surprised if their longer term plan is to whittle the hub option down to just one, their own. Why wouldn’t they? Considerable time and money must have been invested in developing those hubs. It would be understandable if they position themselves to sell as many hubs as they possibly can: one hub for each rim sold.
I don’t like the idea of consumers having fewer configuration choices, but at least Enve didn’t come out with ugly hubs that resemble soup cans like most other wheel brands.
THE DEVIL IN SPOKE COUNTS
Having tinkered with a few old bikes (and still do), I have learned my way through the slippery world of threading: British, Italian, French and Swiss. However, when you are in a threading nightmare, there is at least a way to rationalise the problem (thread direction, thread pitch and thread diameter) by attributing it to, say, cultural diversity. As infuriating as it is when one encounters it unexpectedly, it’s not that difficult to accept it.
Unlike spoke counts.
I decided to finally try tubular wheels earlier this year. For me, the obvious first set was going to be built with Ambrosio Nemesis rims laced to Campagnolo Record hubs (32 holes). One catalyst that pushed me over the edge, into the world of tubs, was that I wore out the Velocity A23 clincher rims on my existing wheelset. Less than 10000 km in, the sidewalls were becoming noticeably concave.
Once I got the Nemesis / Record wheelset, the Chris King R45 hubs that were laced to the Velocity A23 rims needed a new life. My R45s have 24 holes (front) and 28 holes (rear). My choice for the drillings were deliberate. It was a compromise decision between my desire to have a light wheelset and my wheelbuilder Gilbert Cattoir’s view that alloy wheels need to have at least 28 spokes. One could dismiss his opinion as being simply old-fashioned, but it’s actually difficult to do so considering his CV.
After riding the Nemesis / Record wheelset for a bit, I got hooked on tubs despite an unpleasant surprise with FMB tyres. (OK, maybe it shouldn’t have been a surprise since it’s widely documented on the Interwebz…) As such, I was not going to use the R45s for a clincher wheelset, and I was not about to get another alloy tubular wheelset. Therefore, thoughts turned to carbon turbular rims.
Except that the very few carbon road rims that are available as rim-only, such as those from Enve, tend to have 20 holes for the front and 24 holes for the rear. Otherwise, it’s 16 holes (front) and 20 holes (rear). Basically, it is impossible to marry my R45s with brand-name carbon rims because of the different hole counts.
Since I did not want to part with my R45s or let them sit on a shelf (because they are just too good to do either), I ended up getting made-to-order tubular rims from a Chinese manufacturer called Light-Bicycle. 35 mm profile with 24 holes for the front, 45 mm profile with 28 holes for the rear, both toroidal and 25 mm wide, with external nipples. Gilbert built them up for me using Sapim CX-Ray. I mounted a set of 25 mm Veloflex Roubaix and, to my own surprise, am actually quite pleased with them. To be perfectly honest, I had some misgivings about getting inexpensive carbon rims from a Chinese manufacturer, but I did the Raid Pyrénéen on them without any issues. Still, I wish I had other, brand-name choices without having to switch to R45s with a different number of drillings. I don’t think it’s anyone’s fault, just wasn’t an ideal circumstance for me.
Wider rims are all the rage these days for a variety of reasons, including aerodynamics and enabling clincher tyres to form a rounder profile like tubular tyres. 25 mm sounds like an overkill for road cycling, but that’s what I got for my carbon rims. Since I have no plans to roll on 23 mm tyres, I thought I might ‘experiment’ with 25 mm rims, not that I had anything specific in mind as far as the experiment is concerned. Are there real advantages with the 25 mm rims when running tubular tyres? No idea.
Any disadvantages? I assume a 25 mm version is heavier than the 23 mm version of the same profile, so there is probably a slight weight penalty. Otherwise, when running a 25 mm tyre, it impedes visual confirmation of what condition the tyres are in when looking down whilst riding, that is, to see if the tyres aren’t losing air. Unlike clinchers, you can continue rolling after a puncture, albeit at a slow pace. In a slow puncture situation, it can be difficult to sense what’s happening without visual confirmation. I once had a slow puncture but only realised it when a riding buddy pointed out that I might be losing air. I felt a slight mushiness when accelerating but otherwise did not notice anything. Looking down, I didn’t see the tyre width expanding beyond the sides of the rim. It’s difficult not to feel it on a clincher, but here it is different. Enve’s road assortment includes 27 mm rims recommended for use with 25 mm tyres as well as 25 mm rims recommended for use with 23 mm tyres. I imagine visual confirmation is completely out of the question without dismounting first.
I have no idea whether a 25 mm rim with a 25 mm tyre yields any aerodynamic advantages. What I have noticed is that the toroidal shape does make a difference in 2 circumstances. The first is that it seems more or less indifferent to cross winds. Not knowing anything about aerodynamics, I would have guessed that a box section rim like Nemesis would fare much better in a cross wind. Quite the opposite. V-shaped rims like the Mavic CXP 14 is awful in a cross wind, but I was pleasantly surprised that all the fuss about toroidal section might actually have substance. The second is that above 35 kph or thereabouts, it requires noticeably less effort to go faster or maintain speed. I am not a strong cyclist by any measure, so I was surprised to exceed 50 kph on a flat stretch without seeing stars like I probably would with box section rims.
Much has been made about the advantages of carbon rims with respect to torsional and lateral stiffness. Whilst not all carbon rims are made equal, I do notice a difference compared to alloy rims. I am really crap at climbing, so any help I can get is welcome. I noticed that the stiffness of carbon rims make climbing easier. More of the power expended on rotating the pedals actually go to rotating the rear wheel. At first, I was sceptical that it might just be a placebo effect, but I figured it’s not all in the head after 5 days in the Pyrénées.
As mentioned, I had Gilbert build the carbon wheelset using Sapim’s CX-Ray spokes, which are flat spokes designed for aerodynamic advantage, against his recommendation. I specified CX-Ray purely because they are fashionable. Gilbert prefers to use round butted spokes, such as Sport, unless they are for a deep section rim typically seen on triathlon and time trial bikes. Having some very rudimentary understanding of the various types of stiffness with respect to wheels (a decent primer is here), I appreciate his preference. Nonetheless, I asked Gilbert to humour me, and he kindly obliged. If you pick up an unlaced CX-Ray spoke, you will see how flexible it is. Not quite a noodle, but still very flexible. Longer versions required for low to medium profile rims compromise, I am guessing, lateral stiffness, so a reasonable, informed person such as Gilbert, who also happens to be an adviser to Sapim, would not choose CX-Ray for the rims at hand. I am guessing that a part of the reason why he used radial lacing on the non-drive side whilst using 3-cross lacing on the drive side is to make up for the decreased lateral stiffness (as well as trying to even out the spoke tensions on both sides). OK, this is getting a bit too geeky even by my standards…
VALVE STEM CHATTER
I am using a set of Silca Removable Valve Core Extenders for my carbon rims. As far as valve extenders go, they retail for silly money, but the attraction for me was that they are supposed to reduce or eliminate the clicking sound heard from the stem banging against the inside of the hole in the rim. There is a rubber sleeve around the extender to dampen the noise. Except I still got audible clicks once every rotation. Therefore, I resorted to the electrical tape trick. The Silca extenders are still very handsome if useless at preventing chatter. That said, the other, more important claim that Silca make about the extender is its ability to retain air effectively. Unlike other extenders with valve core, they do not require tricks like the use of Teflon tape to prevent air leaking through the valve core threads. Is it worth the extra money not to use Teflon tape? No idea. What I do know is that other branded options plus a roll of Teflon tape is still quite a bit cheaper than a set of Silca extenders.
THERE ARE SEALANTS, AND THERE ARE SEALANTS
The singular reason that previously kept me from using tubular tyres is dealing with punctures. I just couldn’t get my head around this eventuality, until I finally did one day without really understanding why: I just got over it.
I got over the fact that I would need to carry a spare tyre under the saddle or in my jersey pocket, in case a tyre gets a big gash. It’s a bit heavier and bulkier than an inner tube, but it’s not that big a deal. For smaller punctures, I learned that I can sort myself out with a bit of sealant. The beauty of these sealants is that it can also be used effectively with clinchers, for inner tubes.
I also learned that not all sealants are created equal.
Pit Stop from Vittoria / Geax is a widely available sealant. The beauty of Pit Stop is that you do not need to unscrew the valve core, which means that you can use it even if you are using a cheapo tubular or inner tube that does not have a removable valve core. As if that’s not enough to make it seem like manna from heaven, it also inflates the tyre up to 6.5 bar. Sealant and inflater in one. It’s like the cycling equivalent of the Red Sea parting for your exodus.
Except it never works unless the puncture is pin prick size. Anything bigger, and the hole usually is bigger, will expel the foamy sealant right out, making your wheel and you look like Mr Bubbles, leaving you and the wheel all sticky. With a RRP of 10 euros for a single-use canister, it makes a fist-sized white truffle seem inexpensive.
In contrast, Stan’s Tire Sealant is the dog’s bollocks. The 2 oz bottle is easy to carry in a jersey pocket. Take out the valve core, squeeze a bit of the sealant into the tube, screw the valve core back in, spin the wheel for a bit to allow the sealant to get to the puncture, and re-inflate. You don’t even have to take the wheel off the bike, and the sealant actually works. A single bottle costs less than an inner tube and contains enough for several applications. Even if you are rolling on clinchers, I would consider using Stan’s Tire Sealant for the convenience of not having to replace inner tubes. It works for both latex and butyl tubes.
Of course there is a limit to the size of the hole that it can seal. Stan’s claim that holes up to 1/4″ can be sealed. Scale that claim down to 75%, and you would still be ok in most cases. Stan Da Man.
HUBS FROM DIFFERENT WORLDS
As Enve’s tests agree, Chris King hubs are really very good, structurally, mechanically and aesthetically. And, the rear hub makes a lovely sound that makes other noisy hubs seem rather coarse and vulgar. In other words, a King hub has everything.
In contrast, the Campagnolo Record hub is silent, just like the good’ol cup-and-cone models. I much prefer a silent free hub than one that makes hideous noise.
A few hundred kms in, the drive-side lock nut inexplicably became loose, causing the free hub body to become loose. The chain scraped the paint off the dropout as a result. It could have ended badly, but luckily, I got home safely. When I looked for the cause of the clicking sound and took off the rear wheel, I discovered the problem. Clearly, Campagnolo did a crap job assembling the hub. The irony is that in every printed document that comes with any Campagnolo product, there is a warning statement that says that if you don’t do X or if you do Y, you might die. Dott. Valentino Campagnolo, I don’t think everyone finds humour in this like I do.
The other consequence was that the loose bits invited more water ingress (it was a rather wet, mucky ride), so I had a bit of cleaning up to do, which was interesting. I saw that the design and construction of the Record hub is a bit, well, quaint. Of course, the model was introduced when Campagnolo came out with the 9-speed transmission and has basically remained unchanged since then. The genius of Campagnolo’s free hub body design is that it didn’t require modification as transmission standards moved from 9-speed to 10-speed and then to 11-speed, whilst other companies had to redesign the free hub body at each stage of the progression. At the same time, Campagnolo, like other brands, changed their focus to selling complete wheel sets rather than indivicual components like hubs and rims, so they did not develop new hubs to be sold separately.
Compared to the Chris King R45, the Campagnolo Record appears crude. However, the Record hub stayed basically the same since something like 1997. That’s a long time, even in the world of bicycle components. That is not a criticism of the Record hub, but rather, it’s just that the R45 is so good that it’s devastating for most others as a reference point.
IS TUBULAR WORTHWHILE?
Historically, the conventional wisdom was that tubulars are faster than clinchers. With the advances in clincher tyre design and manufacturing and the evolution of clincher rim designs, the paradigm seems to have shifted a bit. This guy certainly thinks so:
Either way, the difference in speed is so marginal that it’s irrelevant for a leisure cyclist like me.
However, when it comes to ride quality and feel, good tubulars are much better than any clincher even though it may be difficult to quantify the difference. I’m very pleased to have made the switch.
If you managed to get through to this sentence, I applaud you.