DT Swiss RR440, one for the wheel builders out there

Since I converted to tubeless tyres, I have been on the hunt for the perfect rim with a brake track, the one that ticks all the boxes. While Archetype ticks most boxes (wide, excellent quality, reasonable price, all drillings available, looking good, decent weight), it’s not a tubeless specific rim and it does not come with an offset drilling option for rear wheels. With 11 speed freehubs, wheels are even more dished than they were five years ago and the tension distribution  between the drive side and the non drive side often exceeds 2 : 1. What it means for the builder is that in order to build a solid wheel, a tension of 1300 Newtons or more on the drive side has become a must. This can result in rims cracking at the holes in the low spoke count options, to the point that now Kirk Pacenti suggests to use rim washers for the popular SL 23 in 24 H rear. A rear rim with offset drillings reduces the tension differencial between drive and non drive side, in some cases even down to 1.5 : 1, which means a lower drive side tension is needed to ensure a strong and durable wheel. Another way of doing it, is to use a “triplet lacing” spoke pattern, or 2 : 1, like many manufacturers do, Campagnolo and Fulcrum most notably. For the builder, this is only possible on a 24 holes rim which is either directionally drilled to accept 2 spokes on the drive side per 1 spoke on the non drive side, or on a rim which has non-directionally drilled holes. The result is a rear wheel where the spoke tensions are almost identical on either side and, as a result, a moderate 1100 N tension is enough in all cases. So, which rim ticks all the boxes now? It all narrows down to the relatively new kid on the block, the DT Swiss 440. This is a tubeless rim with a 21 mm external width, but more crucially a 16 mm internal width (15.8 as measured with my Mitutoyo Vernier). It weighs just under 450 grams in the symmetric option and 460 grams in the asymmetric option. It comes in all the sensible drillings (20-24-28-32) and the symmetric one is centre-drilled, which means a 24 H 2:1 triplet lacing option is possible. If you can’t get hold of a 2: 1 drilled hub, it is fairly straightforward to replace it with a normal 32 holes rear hub, using every other hole on the non drive side. I am getting really fond of this rim, which has the usual DT Swiss exceptional machining, with clear wear indicator on the brake track and a seamless welded joint. In a 20/24 or 20/28 configuration it makes for a nice, service friendly alternative to some classic all time climbers favourites, like the legendary Campagnolo Neutron or the Shimano Dura Ace CL 24, to which it compares quite well even in terms of weight. It is also a tubeless rim, unlike the former pair, which means much safer handling of those Alpine descents, with no risk of blowouts or 60 mph punctures. DSC_3952

Here is a set of 20/28 with asymmetric rear, built on Hope Mono RS hubs radial/3 cross. The rear tension spread is 1200/800 N. 1570 grams for these, with Alpina bladed front spokes and DT Alpine 3/DT revolution at the rear, brass nipples. Obviously lighter hubs would build lighter sets, as an example, the same set with Mig/Mag 70/170 would come at 1420 grams. As it is the case for many light rims, once a pair of Schwalbe ONE tubeless are mounted and inflated, the tension drops about 15%, so they need to be slightly overbuilt.

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