My views on spokes

Two year on (updated Dec. 2014), a few updates on which spokes I like to use and which ones are best avoided.

In wheel building, the choice of spokes and pattern determines whether a wheel will be stiff, light and durable, which are the three requirement one is typically asked to deliver, together with reasonably priced. The general rule is that light spokes and many of them is better then few and heavy ones, as the load is spread better and the spokes suffer reduced fatigue. Yet, most of the machine made wheels are manufactured with few heavy bladed spokes. This is to respond to a certain appearance requirement, alleged aerodynamic benefits and most importantly to cut manufacturing costs. Spoke patterns are also designed with the aim of minimising the range of spoke lengths required, but that’s another story.

These days tapered spokes, namely double butted, are pretty much the norm in wheel building, the exception being wheels for very heavy loads. There are three main sizes available on the market: 2/1.8/2; 2/1.7/2 and 2/1.5/2 mm. DT Swiss competition and Sapim Race for the first, Alpina DB for the second and DT Revolution and Sapim Laser for the last are by and large the most common spokes on the market. The table below gives accurate weights for each of them in the size I use the most, 290-294 mm.

Spoke / nipple Weight /g
DT Comp, Sapim Race 7.1
Alpina DB 6.1
Dt Revolution, Sapim Laser 4.9
12 mm brass nipple 1

I normally use DT Comp. or Alpina DB for rear wheels, as they can take significant load, they have a low tendency to twist and come loose and they show a superior fatigue life in use, when compared to lighter spokes. The lighter DT revolution and Laser are suited to be used in front wheels, where there is virtually no torsional load, as the transmission acts on the rear wheel only. The role of the front wheel is therefore only that of rotating and bearing around 30-40% of the load. In addition, building with light spokes, often leads to twisting of the middle section, especially when spoke thread lock treatments are being used. I have yet to see a rear wheel built with DT revolution that was satisfactory, at least a road wheel with a symmetric rim, where the non drive side tension is low, due to the high dish imposed by the wide freehubs. Typically those lack stiffness and durability and given the weight saving is in the order of 60 grams at best, it is really not worth bothering.

Sapim has recently come up with two new products: the  “superspoke” with a thin 1.4 mm mid section and the D-Light with a 1.65 mm mid section. Although they don’t bring anything different, other than weight saivng over the more common Sapim Laser and Race, they are priced at a premium. I have not been particularly interested in the “superspoke”, which saves 30 grams on a wheel over a product which is already underengineered, but I was interested in the D-light, as a weight saving compromise for light riders. I have recently started using Sapim D-Light more consistently, especially on 32 H disc specific wheels. Combined with the new crop of wide (23-25 mm) rims, these build very stiff wheels. Another interesting feature of D-Light is that the taper begins exactly where the thread ends. This means bottoming out the spoke against the nipple threads becomes impossible and length calculations can be made rounding up instead of rounding down. This also means the D-Light cannot be cut to length and a builder has to make do with the sizes which are available on the market.

Another interesting spoke I am using more often is DT Swiss Alpine III. This is a triple butted spoke, in all similar to DT Competition, but with a stronger 2.34 mm section at the crucial J bend. This results in extra fatigue life and in a spoke ideal to carry heavy weights for long distances.

There is a growing demand for black spokes, to which the supply has not responded yet. Black spokes are available in fewer sizes and they’re more expensive. They are not better, if anything worse, as the surface treatment eats into the steel alloy. They were introduced as an upgrade when spokes were made of low quality steel and did rust. These days you have to do something pretty special to corrode a silver stainless steel spoke with 18% chromium in the alloy!

I am often asked about mini bladed spokes: DT aerolite and Sapim CX Ray are manufactured by forging (squashing) their respective light spokes into a bladed shape, with a thickness of around 0.9-1 mm. They show good fatigue life in the lab, but they have the same drawbacks of DT revolution and Laser, mainly the lack of stiffness. The small aerodynamic advantage is due to a narrowly reduced section (0.6 mm thinner typically) and as such no miracles can be expected. Typically these retail at 3-5 times the price of the corresponsing double butted spoke and in my world they are never worth their money. The thin section results in a great deflection when squeezed in a three point tension gauge which normally results in zero reading for tensions lower than 700 N. In simple words it means the non drive side of a rear wheel has to be built by feel or acoustically tuned to even out the tensions. Moreover, I am still unconvinced they make any sense other than cosmetically on a turbulence plagued rear wheel. I have used Dt Swiss Aerocomp for a few builds: they are very nice spokes, flattened versions of the popular DT Competition. The main drawback is the scarce availability of these in the UK and Europe. Few sizes are imported and distribution is patchy.

* If you are unsure what brand spokes you have, check out this great database http://www.mrrabbit.net/docs/spokeheads/main.html

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