Due to slow progress on current wheel building projects, there hasn't been much to blog. I did procure some Chris King R45 hubs (20/24 hole) for a future project. I've also been adding to my knowledge by corresponding with Ric Hjertberg from Wheel Fanaytk about how spoke flanges and hub shells behave under compression from spokes.
For filler I am profiling the wheelset on my cross bike. I rock a steel frame/fork, so there's not much to be gained by racing a sick light wheelset. Besides, I like to keep it interesting when racing, so in the spirit of that I often make questionable choices in the lines I ride, the equipment I choose, and whether I ride or run a section. (On that last one: always ride.)
I started with a solution looking for a problem: a 20 hole front hub. Later I added another solution looking for a problem: a set of 20/24 hole Velocity Chukker rims. Why that rim?
Those are some sweet specs for a low tire pressure, cyclocross application. What that diagram leaves out: 664 grams for the rim. That's about double the weight of an Ambrosio Nemesis rim or a Mavic Reflex. The 50mm carbon tubulars I use are about 400 grams, and the H Plus Son Archetypes are 450 grams. We're also talking rotating weight, so adding 200 grams handicap for each rim makes things really interesting.
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| Velocity's label includes helpful pictographs that indicate the rim's suggested uses: bike polo and free ride. Note the rim's weld that is clearly visible on the brake track. Not your finest work, Velocity. The tire is a 700 x 32 Continental Gatorskin. |
The front wheel is 20 spoke and built around a C-4 hub that I picked up for cheap. It is a decent design, with the flanges pushed out to 39 mm, a solid forged hub body, and a stiff axle. I used 2.0 mm straight gauge Sapims and 14 mm Sapim Polyax nipples. Lastly, because the hub had been previously laced, I included spoke head washers to eliminate any extra gap at the spoke hole. (I nearly always include spoke washers when lacing wheels to used hubs.) The measured spoke tension with tire mounted and inflated (90 psi) is 115 Kgf. Not too shabby.
I needed a rear wheel. I have several perfectly acceptable ones, but they didn't match my front. (Aesthetics are very important even in cyclocross.) I needed a hub for my 24 hole rim, and short of shelling out serious cash for a Chris King or White Industries, there weren't many options. I did notice the Bike Hub Store was offering 24 rear hubs drilled 16 (drive) and 8 (NDS). That sounded promising--like another solution looking for a problem--so I went for it.
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| The rear wheel with 8 spokes/radial on the NDS; 16 spokes/2 cross on the DS. Lessons were learned. |
The theory behind having half the spokes on the NDS is that those spokes could be equal tension to the DS (instead of 40-60% like a regular, evenly spoked rear wheel). Of course one needs a center drilled rim to do it right. Turns out that the Chukker isn't quite that rim. But I built it anyway and am riding it with no problems.
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| Warning: due to the additional system resources required, do not consume while calculating spoke lengths for a 2:1 wheel, or while lacing said wheel. |
Lessons learned: 1) builds that start as solutions-looking-for-problems will invariably lead to a compromised outcome; 2) the drive side needs to be laced 3x because 2x looks sort of funny; and 3) be prepared to live with the results of your experimentation (because it's unlikely that anyone else would want it and selling it would be irresponsible). That back wheel and I are like Dr Frankenstein and his monster.
