~ Auto Buzz ~: Planning a Wheelbuild: Hypothetical Practicalities

Saturday, 10 December 2016

Planning a Wheelbuild: Hypothetical Practicalities





After my earlier post on wheelbuilding, many expressed an interest in the concrete details of the process: specifically the costs, and where to source supplies. I had planned to cover that in describing my recent 650B project (all done now!). However, as I prepared to write about it, I realised that would not really work. Being more of a re-build than a fresh build, I did not actually buy anything for that project other than spokes, so it won't provide an opportunity to discuss the practicalities of sourcing parts. So instead I’ve decided to dedicate a post to a hypothetical build, starting from scratch.

A crucial part of the wheelbuilding process is the planning stage. Firstly, because we must make sure all parts are compatible. But just as importantly, because the feel, performance and weight of our end-result wheels will depend on the parts we start out with. Therefore, at the onset, it might help to ask ourselves some questions:



What are these wheels for?
Performance, utility, smooth roads, harsh roads, velodrome racing, hilly brevets... you get the idea.

Who are these wheels for? 
Namely, the cyclist's weight, power output and riding style. A heavy and powerful rider will call for different build parameters than a lightweight, gentle rider.

Are there any special properties you want these wheels to have? 
Superior comfort, aerodynamic advantage, crosswind resistance, extra stiffness?... It is good to decide in advance what is important to you, as some of these characteristics are in direct conflict with one another.

Do you care about the weight of the wheels?
If yes, what total weight are you aiming for?

Aside from this, you will of course need to know what size of wheels you are looking to build, and whether you want them to be clincher or tubular, rim-brake/disc-brake/rod-brake compatible, and so on... as well as your budget.

As we consider the answers to these questions, we start to realise there are countless possibilities. And since it would take a book to cover them all, I won’t attempt to do that. Rather I will use myself as an example and explore a possible build I am contemplating for the future.

So first, in answer to the questions above:  I want to build a set of 700C performance wheels, tubular and rim-brake compatible. I weigh 60kg, and am a fairly gentle rider. I would like these wheels to give me an advantage in climbing and acceleration. I would also like the wheels to be crosswind resistant. My target weight is sub-1,300g. As far as budget, I would ideally like to spend under €350, selling my remaining clincher wheels afterward to offset that cost.

With these parameters in mind, I begin to source the required parts: rims, hubs and spokes.



When choosing rims, factors to consider include: rim depth, rim profile, rim weight, and the number of holes the rim is drilled for. Because for my hypothetical build I am looking for climbing wheels that are crosswind resistant, I know that I need a rim with a low, rounded profile. I also know that I want the rims to be lightweight, and that at my weight and riding style I can get away with pushing the envelope in that regard.

So what constitutes a lightweight rim? The current consensus seems to be, that an alloy rim is lightweight if it is in the ballpark of 400g. If I can find one at sub-400g, that would be spectacular. I could also go the carbon fibre route and get the weight down further. But there are complications associated with carbon rims that I do not want to go into here, so to keep things simple let’s stick with alloy.

After searching far and wide, I’ve come across a few options. And here I mean literally just a few, because shallow profile rims that are also super lightweight and tubular, is not a popular combination these days (in fact, a good alternative approach would be to stalk eBay or local bike shops for NOS rims of 80s-90s vintage, when this combination of features was more common). But modern rims do exist that meet these criteria. And the best option I've found so far are the Ambrosio Crono Formula F20 rims. Described as "climbing rims", they are alloy, tubular, low profile, and they weigh 340g per rim! Priced at roughly €65 apiece, depending not he retailer, the cost is very reasonable too. Sounds like I've found my rims.



Now onto the hubs. The rims I chose are available in 28/32/36 hole versions, and the hubs will obviously need to match. Opting for the lower spoke count option (though still not "low," compared to current trends), I am looking for a lightweight hubset with 28 holes.

And what is considered lightweight in the world of modern hubs? Short answer without getting too deeply into it: around 100g for the front, 250g for the rear. It is not especially difficult to find hubs in this weight range across different pricepoints. But it's important to keep in mind other factors, such as quality, durability, and weather-resistance. Some hubs are more delicate than others, and this information is revealed in forum threads and reviews. If you find a hubset that you think might be right for your build, do some research on it before buying, or ask a knowledgeable seller for advice.

My own research led me to consider Bitex hubs. Specifically, I've heard good feedback from several builders now about the RAF12 and RAR12 (front and rear) models, which are said to offer a pretty good combination of light weight and robustness, especially for a low-impact rider such as myself.  These hubs are available in 24/28/32 hole versions and various colours. The weight is 85g for the front and 215g for the rear. The cost is around €120 for the set, depending on the seller.



Once I have my hypothetical rims and hubs in hand, the "fun" can begin. And by fun I mean deciding on your lacing pattern (actually fun) and measuring for spoke length (not at all fun). You will, of course, now also need to decide which spokes to use.

Since I want to make my wheels as crosswind-resistant as possible, I am going to go with round (not bladed) spokes. And since I am going for "climbing wheels," I want lightweight double-butted spokes (pictured on left). Considering that the rider is myself, I know that I can go with lightweight spokes quite safely, especially since - with 28-hole rims and hubs in hand - I'll not be building a wheel with low spoke count.

So how much do "lightweight" spokes weigh? Now, some of the very lightest round alloy spokes available (again we are ignoring carbon here for simplicity's sake), are the mythical Super Spokes (1.8mm-1.4mm-1.8mm; 3.61g per spoke) from the Belgian manufacturer Sapim. However, they are hard to get even in Europe, expensive, and - as I understand from some wheel builders I've spoken with - not without their quirks. The next lightest option, and one I have ready retail access to, are the Sapim Laser spokes (2.0mm-1.5mm-2.0mm; 4.27g per spoke). Both my husband and I have used these spokes already in our first builds, so I already know that I like them and find them easy to work with. My "spoke dealer" Ryan (yes, it's exciting and dangerous as it sounds) offers excellent prices on these, and a bundle of 56 (28 per wheel x 2 wheels) will run me roughly €38.

Now as far as lacing patterns... I see this as an entirely subjective, individual decision. On my 650B wheels I did single cross in the front, then in the rear triple cross on the drivetrain side and radial on the non-drivetrain. I decided on this myself, after reading all sorts of nonsense interesting stuff about optimal comfort vs power transfer, then passionately debating it all with my husband. Whether placebo effect or not, my re-built 650B wheels feel amazing. I may or may not go for the same pattern for this 700C hypothetical build. But in any case, I do not want to start a debate here about which lacing patterns are best, under what circumstances, and why. You can read about all that from a number of sources far more knowledgeable than me and decide for yourself. What I wanted to say though, is that you do have to decide before you order the spokes, as the lacing pattern will be one of the factors determining their length. The other factors are your rim and hub dimensions, and once you measure them very carefully you can determine the spoke length using one of several handy online calculators, including Sapim's own. Typically, the seller you order spokes from will then cut them to size for you.



Of course when ordering spokes and calculating the total weight of a wheel build, let's not forget the nipples (or, alternatively, for the squeamish of mind - "spoke ends").

Most spokes come standard with brass ones (roughly 1g per unit). Or, you can go for the lighter (.4g) and more expensive aluminium ones, with the added bonus of being able to get them in various colours (but also the added drawback of them being easier to crack). A wheelset's worth bundle of festive aluminium nipples will run me roughly €12.

So! Now that I have hypothetically ordered all of my parts, let's total up the weights and costs and see what we've got here:

Ambrosio Crono rims (2): 680g / €130
Bitex RAF/R12 Hubset (1): 300g / €120
Sapim Laser Spokes (56): 240g / €38
Sapim Aluminium Nipples (56): 22g  / €12

Total weight: 1,240g
Total cost: €300

Holy smokes. Is that right? I had to check my numbers after I first calculated this, as it seemed too good to be true. But everything is correct.

The weight is impressively light by current racing wheel standards. And the cost is excellent compared to off-the-shelf wheels. Not to mention that the custom aspects of the build, such as its crosswind resistant characteristics, are not easy to come by off the shelf even at top prices.

I am not planning any new wheel builds just yet. But if I do decide to make myself a set of ultra-light climbing wheels, these are the parts I would use. I hope this breakdown was helpful (despite, for my readers from other continents, the Eurocentric nature of the specs).  If anyone would like to share their own builds - either real or ideal - I am sure we shall all find that extremely interesting.

And with that I bid you a Happy Weekend, pausing to remind you that unused aluminium "spoke ends" make for perfect holiday decor!



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